J. Endocrinol. Invest. 14: 299-304,1991
CASE REPORT
Follicle stimulating hormone - secreting pituitary adenoma: inappropriate secretion and effect of pulsatile luteinizing hormone releasing hormone analogue (buserelin) administration S. Damjanovic, D. Mieic, V. Popovic, M. Petakov, A. Kendereski, M. Sumarae, D. Manojlovic, and J. Micic University Clinical Center, Institute of Endocrinology, Diabetes and Metabolic Diseases, Dr. Subotica 13, 11000 Beograd, Yugoslavia vs 7.1 ± 0.6 mlU/ml, p < 0.001) at day 10, but remained higher than basal level (5.0 ± 0.6, P < 0.001). Free a-SU also rose (2.8 ± 0.4 vs 4.4 ± 1.7 mIU/ml, p < 0.001) after ten days of treatment. The chronic stimulatory effect of analogue on LH with a lack of desensitization suggests tumorous secretion despite a partially preserved negative feedback of testosterone. Low basal LH levels, in some patients with FSH secreting tumors may not be due to tumor mass effect, but rather may be the consequence of altered LH production and/or secretion by the tumor. Although bureselin may not have a therapeutic effect, it is of use in differential diagnosis of hypergonadotrophinemia.
ABSTRACT. A patient with an FSH secreting pituitary adenoma is reported. Elevated FSH and serum free a-subunit (SU) with low levels of LH and testosterone (T) were found. Immunostaining showed the presence of a-SU, FSH-B and LH-B subunits. LHRH analogue (buserelin) was administered in a pulsatile manner, by portable computerized infusion pump sc for ten days. During the first 24 h of treatment FSH, LH (p < 0.001) and T (p < 0.01) rose significantly. Ten days later, the expected desensitization phenomenon did not occur, but further increases of T (8.4 ± 2.6, mean ± SO, vs 17.4 ± 4.1 nmol/I, p < 0.001) and FSH (58.9 ± 9.6 vs 70.7 ± 3.8 mIU/ml, p < 0.001) were registered. LH decreased (12.5 ± 2.4 INTRODUCTION
stimulation (4-6), Dopamine may be of therapeutic importance since it suppresses tumorous serum aSU and in vitro decreases the level of a-SU mRNA (7), Measurement of a-SU in patients with nonfunctioning pituitary adenomas and with gonadotropinomas, in both sera and in tumor cell culture, can be a useful diagnostic marker (8), TRH administration provokes a paradoxical response of gonadotropins in these patients which can aid in diagnosis (9,10), We therefore studied the effect of pulsatile application of LHRH analog (buserelin), bromocriptine and octreotide, on a pituitary gonadotroph adenoma, in a patient with high levels of FSH, a-SU and inappropriately low levels of LH and T, The possible diagnostic role of LHRH analogue is discussed,
Virtually all clinically nonfunctioning pituitary adenomas contain or release gonadotrophins or their subunits in vitro, but in vivo hypersecretion of these rarely occurs (1). Since it has been shown that chronic treatment with LHRH desensitizes normal gonadotrophs, some patients with gonadotroph adenomas have been treated with LHRH analogues, but desensitization has not occurred (2,3). However the pattern of FSH, LH and a-subunit (SU) secretion can change with tumor progression and can be altered by therapeutic intervention (4). In addition, FSH secreting pituitary adenomas do not always respond to LHRH
Key-words. FSH, pituitary adenoma, buserelin, pulsatile infusion pump, usubunit, luteinizing hormone.
CASE REPORT
Correspondence: Svetozar Damjanovic, University Clinical Center, Institute of Endocrinology, Diabetes & Metabolic Diseases, Dr. Subotica 13, 11000 Beograd, Yugoslavia.
A 39-year-old man was first evaluated in June, 1987, following surgery for a large pituitary tumor with suprasellar extension. The histology was reported
Received July 12,1990; accepted January 3,1991.
299
S. Oamjanovic, O. Micic, V. Popovic, et al.
as chromophobe adenoma. He had experienced frontal headaches, for the last few years, and complained of diminished libido and potency. There was no relevant past medical history; he had had a normal puberty. Fertility had not been required. Physical examination revealed normal male secondary sexual characteristics with no evidence of gynecomastia or galactorrhea. He had a normal sized phallus and equal testicular volume of 20 ml by Prader orchidometer. Bilateral optic atrophy was found with left side anopsia and a right temporal hemianopsia. On endocrine evaluation he had elevated levels of FSH with low serum LH and testoterone (T). In March 1988, a second transcranial operation was performed because of tumor recurrence on follow-up CT scan. Immunostaining gave positive reactions with anti-FSH-B and anti-hCG-a by scattered tumor cells. A few cells were also weakly positive with anti-LH-B and sparse cells immunostained with antiprolactin. There was negative staining with anti-GH and anti-ACTH (courtesy of Prof. Dr. I. Doniach). Following the second operation, and elevated FSH with low LH and T levels persisted. There was no evidence of hypopituitarism (Table 1). On postoperative CT scanning residual intrasellar adenoma was detected. Irradiation was suggested, but the patient refused this treatment. He was readmitted to the clinic and the following tests were performed.
Table 1 - Basal endocrine evaluation Hormones
Values
FSH (mIU/ml)
41.2
LH (mIU/ml)
4.8
TSH (mIU/I)
2.3
Normal range 1.0 - 14.0 1.5 - 9.2
< 9.0
Alpha-Subunit (mIU/ml)
2.6
0.06 - 2.15
Testosterone (nmol/I)
6.7
10.4 - 31.3
TT3 (nmol/I)
1.8
1.2 - 2.8
TT4 (nmol/I)
125.4
55.0 - 152.0
Cortisol (nmol/I)
388.2
138.0 - 690.0
PRL (ng/ml)
10.9
hGH (mIU/I)
0.3
2.0 - 14.5
< 10.0
were performed separately (Relefact Hoechst, Frankfurt am Main, West Germany). LH, FSH, TSH and a-SU serum levels were measured before, and 20 and 60 min after peptide administration. A possible desensitizing effect of the LHRH analog buserelin (Suprefact, Hoechst, Frankfurt am Main, West Germany) was looked for. The analog was given sc in a high dose, pulsatile manner by a portable computerized pump (Graseby MS 27, Watford, UK) at 16 pulses per day, 85 Ilg/pulse. T, FSH and LH were sampled hourly for 24 h before, during initiation (day 1) and after ten days of treatment. TSH, PRL and a-SU were collected in the same manner, before and after treatment. FSH, LH, TSH and a-SU were measured after sc administration of octreotide (100 Ilg) hourly for 12 h. An acute bromocriptine (2.5 mg orally) test was performed with samples for FSH, LH, TSH and a-SU collected before, 3 and 5 h after drug administration.
MATERIAL AND METHODS Endocrine evaluation All tests started at 08:00 h, after an overnight fast on separate days. Daytime variations of a-SU, FSH, LH and TSH were determined after sc administration of placebo. Samples were taken, hourly for 12 h. Intravenous TRH (200 Ilg) and LHRH (100 Ilg) tests
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Fig. 1 - The effect of pulsatile sc buserelin administration (16 pulses per day, 85IlQ/pulse) on FSH, LH and testosterone secretion. ** p < 0.0.1, *** P < 0..0.0.1 vs basal (day G).
Buserelin effect in FSH-secreting adenoma
Hormone determinations Plasma FSH, LH and PRL were measured by immunoradiometric assay (IRMA Serono, Milan, Italy), with the interassay coefficient of variation (CV) less than 6.4%, 10.5% and 8.6% respectively. Serum free a-SU was measured by a previously described method using RIA (Biomerica Inc., N. Beach, USA) calibrated against WHO the first IRP 75/569 (hCGa) (11). The interassay CV was less than 7.3%. Crossreactivities for FSH, LH and TSH were less than 2.5%, 0.7% and 0.5%, respectively. TSH was measured by RIA (INEP-Zemun, Yugoslavia) with interassay CV less than 8.3%. T levels were determined by RIA (Biodata, S.pA, Milano, Italy) and interassay CV was less than 10%. T3, T4, GH and cortisol were assayed by commercial RIA kits.
Free a-SU and FSH levels rose significantly after LHRH adninistration (2 .6 and 44.0 to 3.5 and 58.6 mIU/ml, respectively). LH response was preserved (5.4 vs 18.6 mIU/ml) and no effect on TSH secretion was observed. Bromocriptine significantly suppressed a-SU and FSH (2.6 and 43.1 to 1.5 and 30.1 mIU/ml, respectively). TSH decreased (1 .5 vs 0.8 mIU/I) with borderline significance and LH levels did not change significantly (4.9 vs 5.2 mIU/ml). Octreotide suppressed basal TSH levels (2.4 ± 0.7 vs 1.5 ± 05 mIU/I, p < 0.001). Elevated mean basal levels of FSH and a-SU were unaffected by octreotide (39.0 ± 6.5 and 2.5 ± 0.5 mIU/ml, respectively). LH level was not significantly changed by octreotide administration (5.0 ± 0.6 vs 4.7 ± 0.4 mIU/ml). A low serum T (6.5 ± 0.5 nmol/I) with inappropriately low LH (5.0 ± 0.6 mIU/I) was found. A sustained stimulatory effect on FSH secretion was detected (Fig. 1), during the first 24 h and after ten days of treatment with buserelin (58.9 ± 9.6, P < 0.001 vs 70.7 ± 3.8 mIU/ml, p < 0.001). The pattern of FSH and LH secretion differed in response to administration of analog. Stimulation of LH was more pronounced during the first day of treatment (12.5 ± 2.4 mIU/ml , p < 0.001) than after the tenth day (7.1 ± 0.6 mIU/ml), though remained higher (Fig . 1), than basal levels (p < 0.001). T also rose on the first day but was further elevated on day 10 of analog administration (8.4 ± 2.6, P < 0.01 vs 17.4 ± 4.1 nmol/I, p < 0.001) , with regard to basal levels (Fig. 1). Serum free a-SU increased after treatment with buserelin (4.4 ± 1.7 mIU/I, p < 0.001) and prolactin also rose (9.5 ± 2.1 vs 21.2 ± 1.9 ng/ml, p < 0.001), (Fig. 2). Buserelin was without significant effect on TSH secretion (2.4 ± 0.7 vs 2.6 ± 1.5 mIU/I).
Statistical analysis The data are presented as mean ± SD . The unpaired t test was used in statistical analysis. A p value of 0.05 or less was considered significant.
RESULTS Mean basal levels of serum FSH, LH , a-SU and TSH were 41.7 ± 7.6, 5.0 ± 0.6, 2.8 ± 0.4 mlU/ml and 2.4 ± 0.7 mIU/I, respectively. Responses to TRH, LHRH or bromocriptine of over ± 2SD were considered significant, these corresponded to changes over baseline of 35%, 23.8%, 30% and 57% for FSH , LH, a-SU and TSH respectively. A normal TSH response after TRH administration was observed (1.4 vs 6.6 mIU/I), with a 65% increment in serum free a-SU (2.3 vs 3.8 mIU/ml) and a nonsignificant rise in FSH of 25% (38 .5 vs 48.4 mIU/ml) at 20 min. The LH level was not significantly changed (5.8 vs 7.3 mIU/ml).
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Fig. 2 - Serum levels of TSH, a-subunit and prolactin (PRL) after ten days of pulsatile sc buserelin administration. *** p < 0.001 vs basal (day 0)
S. Oamjanovic, D. Mieic, V. Popovic, et at.
LH is biologically active in inducing T secretion which may in turn reflect that negative feedback of Ton LH is partially preserved. The prolactin rise during the analog administration could be induced by T which is an aromatisable androgen and can be converted to estradiol which is known to stimulate PRL secretion (21). FSH and a-SU were suppressed by bromocriptine as previously described (22, 23). We confirmed the results of others (24) that octreotide administration was without effect on tumorous gonadotrophin secretion and serum free a-SUo Only one case of successful LH suppression by octreotide has been reported in a patient with LH secreting pituitary adenoma (25). The differential response of FSH and LH secreting adenomas to octreotide may be explained by the lack of plasma membrane somatostatin receptors or that FSH secreting adenomas express lower number and/or less active receptors (26). The pituitary tumor of our patient was partially autonomous with paradoxical responses of a-SU, FSH and LH to buserelin. However, the lack of desensitization effect seen in this case, in spite of low basal LH levels, may reflect autonomous LH production and thus could be used in the differential diagnosis of hypergonadotrophic states, which as previously described (27), can be problematic.
There was no significant change in a-SU/FSH or aSU/LH ratio before or during treatment with buserelin (6.5 ± 0.8 and 52.1 ± 7.2 vs 5.9 ± 0.2 and 59.1 ± 2.2% respectively). DISCUSSION Immunostaining showed that our patient had an FSH secreting pituitary adenoma with co-secretion of aSU. We confirmed the findings of others in that these tumors can respond to TRH administration with a paradoxical increment of gonadotrophins (9, 10). Co-response of a-SU with FSH is consistent with tumorous secretion (7, 12). Most reports that relate to patients with pituitary gonadotroph adenomas describe large tumors which frequently recur following operation, as was the case in our patient. The paradoxical response to TRH is consistent with tumor recurrence. As most nonsecreting adenomas contain plasma membrane receptors for TRH, this may be linked to tumor mitotic activity (13). Gonadotrophin increment by LHRH in patients with FSH secreting adenomas has been reported (6, 14). Almost all 'so-called', non secretory pituitary adenomas contain mRNA-s for the a and B subunits of glycoprotein hormones (15). Immunostaining showed the presence of LH-B, but could not distinguish between subunit of tumorous or nontumorous origin. However, buserelin caused sustained stimulatory effects on FSH and free a-SU secretion which is consistent with other reports (16). An initial increment of LH without subsequent desensitization, also suggests tumorous secretion. A differential regulation of LH-B and LH-a during the down regulatory phase of LHRH action has been reported in the rat (17,18). As the a-SU/LH ratio did not change, this also suggests the absence of down regulation by buserelin. There could be a defect in the production of LH-B and/or in the process of association of a and LH-B subunits within the tumorous cell itself. A low level of testosterone in rats is known to be a potent stimulator of LH production (19), as our patient similarly had low levels ofT the lack of an LH response suggests abnormal LH regulation, synthesis or secretion by tumorous cells. Because buserelin administration was able to stimulate LH production without desensitization this also suggests tumorous rather than normal gonadotroph function. Therefore the low basal level of LH in our case can not be fully explained as a reflection of tumour mass effect on preserved normal gonadotroph cells (20). The first day of treatment with the analog gave higher increments of LH than T. An inverse situation was found at the end of the treatment. Thus secreted
ACKNOWLEDGMENT The authors are indebted to Prof. Dr. I. Doniach (St. Bartholomew's Hospital, London), for kindly performing immunostaining studies in our patient.
REFERENCES 1. Kwekkeboom O.J., de Jong FH, Lamberts SW.J. Gonadotropin release by clinically nonfunctioning and gonadotroph pituitary adenomas in vivo and in vitro: Relation to sex and effects of thyrotropin-releasing hormone, and bromocriptine. J. Clin. Endocrinol. Metab. 68.' 1128, 1989. 2. Roman SH, Goldstein M., Kourides lA, Comite F., Bardin W.c., Krieger OT The luteinizing hormone releasing hormone (LHRH) agonist (0- Trp 6-P r09-NEt) LHRH increased rather than lowered LH and a-subunit levels in a patient with LH-secreting pituitary tumor. J. Clin. Endocrinol. Metab. 58: 313,1984. 3. Klinanski A, Deutch P., Jameson J.L., Ridgway E.C., Crowley W.C., Zervas NT
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Buserelin effect in FSH-secreting adenoma
Luteinizing hormone (LH) and a-subunit secreting adenoma: Biosyntetic characteriterization and clinical studies. J. Clin . Endocrinol. Metab. 64 536, 1987.
In: Landolt AM., Heitz P.U., Zapf J., Girard J., Del Poso E. (Eds.), Advances in pituitary adenoma research. Pergamon Press , Oxford , 1988, p. 67.
4. Borges J.L.C., Ridgway E.C. , Kovacs K. , Rogol AD ., Thorner M.O. Follicle-stimulating hormone-secreting pituitary tumor with concomitant elevation of serum a-subunit levels. J. Clin. Endocrinol. Metab. 58: 937 , 1984.
14. Peterson R.E., Kourdies lA , Horwith M., Darracot V. Jr, Saxena B.B., Fraser RAR. Luteinizing hormone- and a-subunit-secreting pituitary tumor: Positive feedback of estrogen. J. Clin. Endocrinol. Metab. 52: 692, 1981.
5. Friend J.N. , Judge D.M. , Sherman B.M ., Santen R.J.
15. Jameson L.L., Lindell C .M., Habener J .F. Gonadotropin and thyrotropin a- and B-subunit gene expression in normal and neplastic tissues characterised using specific messenger ribonucleic acid hybridization probes. J. Clin. Endocrinol. Metab. 64: 319,1986.
FSH secreting pituitary adenomas: Stimulation and suppression studies in two patients. J. Clin . Endocinol. Metab. 43: 650, 1976. 6. Cunningham G.R., Huckins C. An FSH and prolactin-secreting pituitary tumor: Pituitary dynamics and testicular histology. J. Clin. Endocrinol. Metab. 44: 248, 1977.
16. Duet M, Warnet A, Roche D., Seret D., Diop S.N., Lubetzki J. Gonadotropic adenoma with abnormal secretory pattern: Case report adenoma. In: Landolt AM., Heitz P.U., Zapf J., Girard J. , Del Pozo E. (Eds.) , Advances in pituitary adenoma research. Pergamon Press., Oxford, 1988, p. 433.
7. Klibanski A, Shupnik M.A., Bikkal H.A ., Black P. McL., Kliman B., Zervas N.T. Dopaminergic regulation of a-subunit secretion and messenger ribonucleic acid levels in a-secreting pituitary tumors. J. Clin. Endocrinol. Metab. 65: 96, 1988.
17. Yuan O.x., Swerdloff R.S., Bhasin S. Differential regulation of rat luteinizing hormone aand B-subunits during the stimulatory ahd down-regulatory phases of gonadotropin-releasing hormone action . Endocrinology. 122: 504, 1988.
8. Demura R. , Kubo J.O., Odagiri E., Demura H., Kitamura K. , Shizume K. , The significance of a-subunit as a tumor marker for gonadotropin-producing pituitary adenomas. J. Clin . Endocrinol. Metab. 63: 564, 1986.
18. Vogel D.L., Magner J .A., Sherins R.J., Weintraub B.D. Biosynthesis, glycosylation and secretion of rat luteinizing hormone a- and B-subunits: Differential effects of orchiectomy and gonadotropin-releasing hormone. Endocrinology 119: 202, 1986.
9. Snyder P.J., Sterling F.H. Hypersecretion of LH and FSH by a pituitary adenoma. J. Clin. Endocrinol. Metab. 42: 544, 1976. 10. Snyder P.P.J., Muzyka R., Johnson J., Utiger R.D. Thyrotropin-releasing hormone provokes abnormal follicle-stimulating hormone (FSH) and luteinizing hormone responses in men who have pituitary adenomas and FSH hypersecretion. J. Clin . Endocrinol. Metab . 51: 744,1980.
19. Gharib S.D., Bowers S.M. , Need L.R. , Chin WW. Regulation of rat luteinizing hormone subunit messenger ribonucleic acids by gonadal steroid hormones. J. Clin . Invest. 77: 582 , 1986.
11. Whitcomb RW., Sangha J.S., Schneyer A.L., Crowley W.F. Jr. Improved measurement of free alpha subunit of glycoprotein hormones by assay with use of monoclonal antibody. Clin. Chem. 34: 2022, 1988.
20. Snyder P.J. Gonadotroph adenomas of the pituitary. J. Clin. Endocrinol. Metab. 6: 552, 1985. 21. Labrie F., Ferland L., Denizeau F., Beaulieu M. Sex steroids interact with dopamine at the hypothalamic and pituitary levels to modulate prolactin secretion. J. Steroid Biochem. 12:323,1980.
12. Kourides 1.0., Weintraub B.D., Rosen S.w., Ridgway E.C., Kliman B., Maloof F. Secretion of alpha subunit of glycoprotein hornones by pituitary adenomas. J. Clin. Endocrinol. Metab. 43: 97, 1976.
22. Berezin M., Olchovsky D ., Pines A. , Tadmor R. , Lunenfeld B. Reduction of follicle-stimulating hormone (FSH) secretion in FSH producing pituitary adenoma by bromocriptine. J. Clin. Endocrinol. Metab. 59: 1220, 1984.
13. Peillon F., Bression B., Le Dafniet M., Brandi AM., Li J .Y. , Pagesy P., Birman P., Blumberg-Tick J., Michard M., Kujas M., Racadot J. Receptor studies in pituitary adenomas. Do they contribute to a better understanding of their pathogenesis?
23. Vance M.L., Ridgway E.C., Thorner M.O. Follicle-stimulating hormone- and a-subunit-secret-
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s.
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Response of luteinizing hormone secreting pituitary adenoma to a long acting somatostatin analogue. Acta Endocrinol. (Copenh.) 11B: 587, 1988. 26. Reubi J.C., Lamberts S.w.J., Maurer R. Somatostatin receptors in normal and tumoral tissue. Horm. Res. 29: 65, 1988.
ing pituitary tumor treated with bromocriptine. J. Clin. Endocrinol. Metab. 61: 580,1985. 24. Sassolas G., Serusclat P., Claustrat B, Trouillas J., Merabet S., Cohen R., Souquet J.C. Plasma alpha-subunit levels during the treatment of pituitary adenomas with the somatostatin analog (SMS 201-995). Horm. Res. 29: 124,1988. 25. Vas P., Croughs R.J.M., Thijssen J.w., van't Verlaat J.w, van Ginkel LA
27. Cook D.M., Watkins S., Snyder P.J. Gonadotrophin-secreting adenomas masquerading as primary ovarian failure. Clin. Endocrinol. (Oxf.) 25: 729, 1986.
304
CASE REPORT
Follicle stimulating hormone - secreting pituitary adenoma: inappropriate secretion and effect of pulsatile luteinizing hormone releasing hormone analogue (buserelin) administration S. Damjanovic, D. Mieic, V. Popovic, M. Petakov, A. Kendereski, M. Sumarae, D. Manojlovic, and J. Micic University Clinical Center, Institute of Endocrinology, Diabetes and Metabolic Diseases, Dr. Subotica 13, 11000 Beograd, Yugoslavia vs 7.1 ± 0.6 mlU/ml, p < 0.001) at day 10, but remained higher than basal level (5.0 ± 0.6, P < 0.001). Free a-SU also rose (2.8 ± 0.4 vs 4.4 ± 1.7 mIU/ml, p < 0.001) after ten days of treatment. The chronic stimulatory effect of analogue on LH with a lack of desensitization suggests tumorous secretion despite a partially preserved negative feedback of testosterone. Low basal LH levels, in some patients with FSH secreting tumors may not be due to tumor mass effect, but rather may be the consequence of altered LH production and/or secretion by the tumor. Although bureselin may not have a therapeutic effect, it is of use in differential diagnosis of hypergonadotrophinemia.
ABSTRACT. A patient with an FSH secreting pituitary adenoma is reported. Elevated FSH and serum free a-subunit (SU) with low levels of LH and testosterone (T) were found. Immunostaining showed the presence of a-SU, FSH-B and LH-B subunits. LHRH analogue (buserelin) was administered in a pulsatile manner, by portable computerized infusion pump sc for ten days. During the first 24 h of treatment FSH, LH (p < 0.001) and T (p < 0.01) rose significantly. Ten days later, the expected desensitization phenomenon did not occur, but further increases of T (8.4 ± 2.6, mean ± SO, vs 17.4 ± 4.1 nmol/I, p < 0.001) and FSH (58.9 ± 9.6 vs 70.7 ± 3.8 mIU/ml, p < 0.001) were registered. LH decreased (12.5 ± 2.4 INTRODUCTION
stimulation (4-6), Dopamine may be of therapeutic importance since it suppresses tumorous serum aSU and in vitro decreases the level of a-SU mRNA (7), Measurement of a-SU in patients with nonfunctioning pituitary adenomas and with gonadotropinomas, in both sera and in tumor cell culture, can be a useful diagnostic marker (8), TRH administration provokes a paradoxical response of gonadotropins in these patients which can aid in diagnosis (9,10), We therefore studied the effect of pulsatile application of LHRH analog (buserelin), bromocriptine and octreotide, on a pituitary gonadotroph adenoma, in a patient with high levels of FSH, a-SU and inappropriately low levels of LH and T, The possible diagnostic role of LHRH analogue is discussed,
Virtually all clinically nonfunctioning pituitary adenomas contain or release gonadotrophins or their subunits in vitro, but in vivo hypersecretion of these rarely occurs (1). Since it has been shown that chronic treatment with LHRH desensitizes normal gonadotrophs, some patients with gonadotroph adenomas have been treated with LHRH analogues, but desensitization has not occurred (2,3). However the pattern of FSH, LH and a-subunit (SU) secretion can change with tumor progression and can be altered by therapeutic intervention (4). In addition, FSH secreting pituitary adenomas do not always respond to LHRH
Key-words. FSH, pituitary adenoma, buserelin, pulsatile infusion pump, usubunit, luteinizing hormone.
CASE REPORT
Correspondence: Svetozar Damjanovic, University Clinical Center, Institute of Endocrinology, Diabetes & Metabolic Diseases, Dr. Subotica 13, 11000 Beograd, Yugoslavia.
A 39-year-old man was first evaluated in June, 1987, following surgery for a large pituitary tumor with suprasellar extension. The histology was reported
Received July 12,1990; accepted January 3,1991.
299
S. Oamjanovic, O. Micic, V. Popovic, et al.
as chromophobe adenoma. He had experienced frontal headaches, for the last few years, and complained of diminished libido and potency. There was no relevant past medical history; he had had a normal puberty. Fertility had not been required. Physical examination revealed normal male secondary sexual characteristics with no evidence of gynecomastia or galactorrhea. He had a normal sized phallus and equal testicular volume of 20 ml by Prader orchidometer. Bilateral optic atrophy was found with left side anopsia and a right temporal hemianopsia. On endocrine evaluation he had elevated levels of FSH with low serum LH and testoterone (T). In March 1988, a second transcranial operation was performed because of tumor recurrence on follow-up CT scan. Immunostaining gave positive reactions with anti-FSH-B and anti-hCG-a by scattered tumor cells. A few cells were also weakly positive with anti-LH-B and sparse cells immunostained with antiprolactin. There was negative staining with anti-GH and anti-ACTH (courtesy of Prof. Dr. I. Doniach). Following the second operation, and elevated FSH with low LH and T levels persisted. There was no evidence of hypopituitarism (Table 1). On postoperative CT scanning residual intrasellar adenoma was detected. Irradiation was suggested, but the patient refused this treatment. He was readmitted to the clinic and the following tests were performed.
Table 1 - Basal endocrine evaluation Hormones
Values
FSH (mIU/ml)
41.2
LH (mIU/ml)
4.8
TSH (mIU/I)
2.3
Normal range 1.0 - 14.0 1.5 - 9.2
< 9.0
Alpha-Subunit (mIU/ml)
2.6
0.06 - 2.15
Testosterone (nmol/I)
6.7
10.4 - 31.3
TT3 (nmol/I)
1.8
1.2 - 2.8
TT4 (nmol/I)
125.4
55.0 - 152.0
Cortisol (nmol/I)
388.2
138.0 - 690.0
PRL (ng/ml)
10.9
hGH (mIU/I)
0.3
2.0 - 14.5
< 10.0
were performed separately (Relefact Hoechst, Frankfurt am Main, West Germany). LH, FSH, TSH and a-SU serum levels were measured before, and 20 and 60 min after peptide administration. A possible desensitizing effect of the LHRH analog buserelin (Suprefact, Hoechst, Frankfurt am Main, West Germany) was looked for. The analog was given sc in a high dose, pulsatile manner by a portable computerized pump (Graseby MS 27, Watford, UK) at 16 pulses per day, 85 Ilg/pulse. T, FSH and LH were sampled hourly for 24 h before, during initiation (day 1) and after ten days of treatment. TSH, PRL and a-SU were collected in the same manner, before and after treatment. FSH, LH, TSH and a-SU were measured after sc administration of octreotide (100 Ilg) hourly for 12 h. An acute bromocriptine (2.5 mg orally) test was performed with samples for FSH, LH, TSH and a-SU collected before, 3 and 5 h after drug administration.
MATERIAL AND METHODS Endocrine evaluation All tests started at 08:00 h, after an overnight fast on separate days. Daytime variations of a-SU, FSH, LH and TSH were determined after sc administration of placebo. Samples were taken, hourly for 12 h. Intravenous TRH (200 Ilg) and LHRH (100 Ilg) tests
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Buserelin effect in FSH-secreting adenoma
Hormone determinations Plasma FSH, LH and PRL were measured by immunoradiometric assay (IRMA Serono, Milan, Italy), with the interassay coefficient of variation (CV) less than 6.4%, 10.5% and 8.6% respectively. Serum free a-SU was measured by a previously described method using RIA (Biomerica Inc., N. Beach, USA) calibrated against WHO the first IRP 75/569 (hCGa) (11). The interassay CV was less than 7.3%. Crossreactivities for FSH, LH and TSH were less than 2.5%, 0.7% and 0.5%, respectively. TSH was measured by RIA (INEP-Zemun, Yugoslavia) with interassay CV less than 8.3%. T levels were determined by RIA (Biodata, S.pA, Milano, Italy) and interassay CV was less than 10%. T3, T4, GH and cortisol were assayed by commercial RIA kits.
Free a-SU and FSH levels rose significantly after LHRH adninistration (2 .6 and 44.0 to 3.5 and 58.6 mIU/ml, respectively). LH response was preserved (5.4 vs 18.6 mIU/ml) and no effect on TSH secretion was observed. Bromocriptine significantly suppressed a-SU and FSH (2.6 and 43.1 to 1.5 and 30.1 mIU/ml, respectively). TSH decreased (1 .5 vs 0.8 mIU/I) with borderline significance and LH levels did not change significantly (4.9 vs 5.2 mIU/ml). Octreotide suppressed basal TSH levels (2.4 ± 0.7 vs 1.5 ± 05 mIU/I, p < 0.001). Elevated mean basal levels of FSH and a-SU were unaffected by octreotide (39.0 ± 6.5 and 2.5 ± 0.5 mIU/ml, respectively). LH level was not significantly changed by octreotide administration (5.0 ± 0.6 vs 4.7 ± 0.4 mIU/ml). A low serum T (6.5 ± 0.5 nmol/I) with inappropriately low LH (5.0 ± 0.6 mIU/I) was found. A sustained stimulatory effect on FSH secretion was detected (Fig. 1), during the first 24 h and after ten days of treatment with buserelin (58.9 ± 9.6, P < 0.001 vs 70.7 ± 3.8 mIU/ml, p < 0.001). The pattern of FSH and LH secretion differed in response to administration of analog. Stimulation of LH was more pronounced during the first day of treatment (12.5 ± 2.4 mIU/ml , p < 0.001) than after the tenth day (7.1 ± 0.6 mIU/ml), though remained higher (Fig . 1), than basal levels (p < 0.001). T also rose on the first day but was further elevated on day 10 of analog administration (8.4 ± 2.6, P < 0.01 vs 17.4 ± 4.1 nmol/I, p < 0.001) , with regard to basal levels (Fig. 1). Serum free a-SU increased after treatment with buserelin (4.4 ± 1.7 mIU/I, p < 0.001) and prolactin also rose (9.5 ± 2.1 vs 21.2 ± 1.9 ng/ml, p < 0.001), (Fig. 2). Buserelin was without significant effect on TSH secretion (2.4 ± 0.7 vs 2.6 ± 1.5 mIU/I).
Statistical analysis The data are presented as mean ± SD . The unpaired t test was used in statistical analysis. A p value of 0.05 or less was considered significant.
RESULTS Mean basal levels of serum FSH, LH , a-SU and TSH were 41.7 ± 7.6, 5.0 ± 0.6, 2.8 ± 0.4 mlU/ml and 2.4 ± 0.7 mIU/I, respectively. Responses to TRH, LHRH or bromocriptine of over ± 2SD were considered significant, these corresponded to changes over baseline of 35%, 23.8%, 30% and 57% for FSH , LH, a-SU and TSH respectively. A normal TSH response after TRH administration was observed (1.4 vs 6.6 mIU/I), with a 65% increment in serum free a-SU (2.3 vs 3.8 mIU/ml) and a nonsignificant rise in FSH of 25% (38 .5 vs 48.4 mIU/ml) at 20 min. The LH level was not significantly changed (5.8 vs 7.3 mIU/ml).
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S. Oamjanovic, D. Mieic, V. Popovic, et at.
LH is biologically active in inducing T secretion which may in turn reflect that negative feedback of Ton LH is partially preserved. The prolactin rise during the analog administration could be induced by T which is an aromatisable androgen and can be converted to estradiol which is known to stimulate PRL secretion (21). FSH and a-SU were suppressed by bromocriptine as previously described (22, 23). We confirmed the results of others (24) that octreotide administration was without effect on tumorous gonadotrophin secretion and serum free a-SUo Only one case of successful LH suppression by octreotide has been reported in a patient with LH secreting pituitary adenoma (25). The differential response of FSH and LH secreting adenomas to octreotide may be explained by the lack of plasma membrane somatostatin receptors or that FSH secreting adenomas express lower number and/or less active receptors (26). The pituitary tumor of our patient was partially autonomous with paradoxical responses of a-SU, FSH and LH to buserelin. However, the lack of desensitization effect seen in this case, in spite of low basal LH levels, may reflect autonomous LH production and thus could be used in the differential diagnosis of hypergonadotrophic states, which as previously described (27), can be problematic.
There was no significant change in a-SU/FSH or aSU/LH ratio before or during treatment with buserelin (6.5 ± 0.8 and 52.1 ± 7.2 vs 5.9 ± 0.2 and 59.1 ± 2.2% respectively). DISCUSSION Immunostaining showed that our patient had an FSH secreting pituitary adenoma with co-secretion of aSU. We confirmed the findings of others in that these tumors can respond to TRH administration with a paradoxical increment of gonadotrophins (9, 10). Co-response of a-SU with FSH is consistent with tumorous secretion (7, 12). Most reports that relate to patients with pituitary gonadotroph adenomas describe large tumors which frequently recur following operation, as was the case in our patient. The paradoxical response to TRH is consistent with tumor recurrence. As most nonsecreting adenomas contain plasma membrane receptors for TRH, this may be linked to tumor mitotic activity (13). Gonadotrophin increment by LHRH in patients with FSH secreting adenomas has been reported (6, 14). Almost all 'so-called', non secretory pituitary adenomas contain mRNA-s for the a and B subunits of glycoprotein hormones (15). Immunostaining showed the presence of LH-B, but could not distinguish between subunit of tumorous or nontumorous origin. However, buserelin caused sustained stimulatory effects on FSH and free a-SU secretion which is consistent with other reports (16). An initial increment of LH without subsequent desensitization, also suggests tumorous secretion. A differential regulation of LH-B and LH-a during the down regulatory phase of LHRH action has been reported in the rat (17,18). As the a-SU/LH ratio did not change, this also suggests the absence of down regulation by buserelin. There could be a defect in the production of LH-B and/or in the process of association of a and LH-B subunits within the tumorous cell itself. A low level of testosterone in rats is known to be a potent stimulator of LH production (19), as our patient similarly had low levels ofT the lack of an LH response suggests abnormal LH regulation, synthesis or secretion by tumorous cells. Because buserelin administration was able to stimulate LH production without desensitization this also suggests tumorous rather than normal gonadotroph function. Therefore the low basal level of LH in our case can not be fully explained as a reflection of tumour mass effect on preserved normal gonadotroph cells (20). The first day of treatment with the analog gave higher increments of LH than T. An inverse situation was found at the end of the treatment. Thus secreted
ACKNOWLEDGMENT The authors are indebted to Prof. Dr. I. Doniach (St. Bartholomew's Hospital, London), for kindly performing immunostaining studies in our patient.
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