J. Endocrinol. Invest. 1.' 359, 1978
SHORT COMMUNICATION
Circulating prolactin and its response to TRH following administration of testosterone undecanoate in normal men 1 P.M. Kicovic*, M. Luisi**, F. Franchi** and S. Krempl* *Scientific Development Group, Medical U nit. Organon, Oss, Holland and **Endocrine Unit of C.N.R., 1 st Medical Clinic, University Hospital, Pisa, Italy
ABSTRACT. To investigate the effect of orally administered testosterone undecanoate (TU) on circulating prolactin (PRL) and PRL response to TRH stimulation, 8 eugonadal male volunteers, aged 19-30, presenting with normal plasma levels of FSH, LH, testosterone (T), estradiol (E2) and PRL, were given 120 mg/day of TU for 6 days. Plasma PRL levels were measured daily during the pre-treatment phase (3 days), treatment phase (6 days) and post-treatment phase (3 days) by radioimmunoassay. The TRH Test (200 I1g iv) was done on the 3rd day of the pretreatment phase and on the treatment phase. No sig nficant changes in circulating PRL levels or in PRL response to TRH stimulation were observed. Plasma T and E2 levels showed a slight, but not significant tendency to increase, while gonadotropin levels remained unchanged. INTRODUCTION
MATERIALS AND METHODS
Several recent studies (1-4) have shown that orally administered testosterone undecanoate (TU) is an effective form of substitution therapy in male hypogoladal patients. In hypergonadotropic hypogonadal ,11ales TU significantly suppressed the levels of circulating FSH and LH, while in hypogonadotropic hypogonadal males both gonadotropins were increased (3). In the same study a normalization of prolactin (PRL) response to TRH stimulation was observed in patients with poor PRL response prior to the TU therapy. In normal men, however, TU did not alter the functional capacity of the gonadotropic area of the hypothalamic-pituitary axis, as assessed by means of the LHRH (5) and clomiphene tests (6). All these observations suggested that TU displays interesting properties with regard to hypothalamic-pituitary function. Evidence that estrogens promote pituitary PRL secretion has recently been well documented (710). To our knowledge, no data on effects of exogenously administered andr.ogens on the pituitary PRL secretion in eugonadal men are available. This study examines whether changes in circulating PRL and PRL response to TRH occur during administration of oral TU to normal men.
Eight normal men between the ages of 19 and 30 agreed to partecipate in this study and served as volunteers. None of the subjects had any illness or took any medication prior to, or during, the present study. Physical examination and X-ray of sella turcica did not reveal abnormalities. Basal plasma FSH, LH, testosterone (T), estradiol (E2) and PRL levels in all subjects were within the normal ranges. Venous blood samples for determination of plasm'a PRL levels were obtained daily during the pretreatment phase (3 days), during the treatment phase (120 mg/ day of TU, given as 3x1 capsule of 40 mg at meals, for 6 days), and during the post-treatment phase (3 days), always between 08:00 and 08:30 h. The TRH test was performed twice: on the 3rd day of the pretreatment phase and on the 6th day of the treatment phase, in the morning after an overnight fast. Synthetic TRH (200 Jig) was administered intravenously as a bolus injection at time 0 through an indwelling scalp vein needle. Blood was sampled at -15, 0, 10, 20, 30, 60 and 120 minutes for determination of the plasma PRL concentrations. On the 6th day of the treatment phase plasma samples for determination of FSH, LH, T and E2 levels were also obtained. Each blood sample was immediately centrifuged, and the plasma was separated and frozen at -20 C until analized.
1 Supported. in part. by the grant no. 76.0t 527.04/11 511 30 from the Consiglio Nazionale delle Ricerche (Roma)
Plasma FSH and LH were measured by using RIAmat-FSH (5423 Byk-Mallinkrodt) and RIA-mat-LH (5263 Byk-Mallinkrodt), respectively. The amounts of FSH and LH were calculated relative to MRC Standards 68/39 and 68/40, respectively, and expressed
Key-words: Testosterone undecanoate, plasma PRL. TRH test, normal men.
Correpondence: Prof. P.M. Kicovic • Medical Unit. SDG. Organon. Oss. Holland Received May 30. 1978; accepted August 31. 1978
359
P.M. Kicovic, M. Luisi, F. Franchi, and S. Krempl
Table 1 - Plasma hormone levels (mean after TU medica tion (no. = 8).
Testosterone LH (nmol / I) 1 (mU / ml)
FSH (mU/ml)
Before TU 2.8±0.9 6.2 ± 1.2 2.3 ± 0.7 3 6.0 ± 09 3
After TU 1 _
1 nmol /l "" 288
± SO) before and
18.7± 3.1
All assays were carried out in duplicate, at the same time and with the same batches of reagents. Data were analysed by means of the t test of mean differences. For PRL the value during treatment of post-treatment minus the pretreatment value (calculated as an average of 3 pretreatment values) was used as variable value for the t test. Calculation of cumulative responses of PRL to TRH was done according to Franchimont et al. (13).
Estradiol (pmol / I) 2 147.4±20.8
20.6 ± 3.0 3 154.4 ± 18.9 3
ng / l00 ml
2 _ 1 pmoi/l "" 0.27 pg /m!.
3 - NS.
RESULTS Plasma FSH , LH , T and E2levels, measured before and after the medication with TU, are shown in Table 1. As can be seen, FSH and LH levels remained unchanged, while both T and E2 levels slightly increased. The changes did not reach significant levels. Mean (± SO) plasma PRL levels, estimated at baseline
in mlU / ml. Plasma T was measured as previously described by Luisi et al. (11). RIA-kit (CEA-IRESORIN) was used for the determination of plasma E2. Plasma PRL was estimated according to Ciardella et al. (12), using Biodata kit. Table 2 - Mean (± SO) circulating PRL at baseline (n o. = 8)
Treatment
Pre-treatment
Phase
-2 8.4 ± 2.2
Day PRL (ng/ml)
-1
o
8.6 ± 2.1
8.0 ± 1.9
84 ± 2.3
Post-treatment
1
2
3
4
5
6
8.3 ±1 .9
7.9 ± 1.6
8.5 ±2.2
8.7 ± 2.1
9.2 ± 2.1
1 9.0 ± 2.3
1
2
3
8.6 ± 1.9
8.7 2.2
±
1 No stat isti ca lly significant differences were foun d.
1500
48
Cumulative response
TRH.200ug 40
:" '
-- -at -
1000
32
--..
E --..
0>
c:
....i
, ,,,
.t: N
...
0>
c:
24
C :>
a:
'" ..:r
0-
Q)
..........
16
500
8
,
- 15 0 Minutes
,
10
20
30
120
60
beforeTU
after TU
Fig 1 - Mean (± SO) PRL release and cumulative response to 200 I1g of TRH before ( - ) and after ( - - - ) TU medicatIOn (no
360
= 8)
Testosterone undecanoate, PRL response to TRH
during the pretreatment, treatment and post-treatment phases, are given in Table 2. Mean plasma PRL tended to increase during treatment, but the differences were not significant. Figure 1 illustrates mean (± SO) plasma PRL,concentration during the TRH test performed on the 3rd day of the pretreatment phase and on the 6th day of the treatment phase. Plasma PRL cumulative responses (mean ± SO) are also presented. Mean peak PRL values were recorded 20 minutes after TRH administration in both tests. Before TU medication PRL rose from 7.9 ± 1.8 to 32.5 ± 9.1 ng/ml. On the 6th treatment day PRL rose from 9.1 ± 2.0 to 37.4 ± 8.8 ng/ml. After having reached peak values at 20 minutes, PRL levels declined progressively to the levels slighlty higher than pretreatment ones at the and of both tests. Cumulative responses before end after TU medication also showed minor differences, i.e. 1012 ± 350 and 1058 ± 237 ng/2h, respectively.
Effects of oral testosterone undecanoate in hypogonadal male patients. Acta Endocrinol. (Kbh) (Suppl) 212: 118, 1977. 4. Mies R., Krempl S. Effects of oral testosterone undecanoate on plasma hormones and clinical symptomatology in hypo gonadal male patients Acta Endocrinol. (Kbh) (Suppl) 212: 119, 1977 5. Mies R., Kicovic P.M. Effects of testosterone undecanoate administration on LH ad FSH response during the LH-RH Test in healthy male volunteers. Andrologia 9( 3): 233, 1977. 6. Luisi M., Eliasson R., Kicovic P.M., Franchi F., Alicicco E. Hypothalamic-pituitary responsiveness to the clomiphene stimulation during a placebo controlled study of testosterone undecanoate therapy in normal men. Proc. Intern. Symp. Rec. Progr. Androl., L'Aquila (1977), Academic Press, London-New York, 1978 (in press). 7. Frantz A.G., Kleinberg D.L., Noel G.L. Studies on prolactin in man. Recent Progr. Horm. Res. 28: 527, 1972.
DISCUSSION
8. Yen SS.C., Ehara Y., Siler T.M. Augmentation of prolactin secretion by estrogen in hypogonadal women. J. Clin. Invest. 53: 652,1974.
The present study demonstrates that oral TU, given in a dose of 120 mg/day for 6 days to normal male volunteers, does not influence either circulating PRL or its response to TRH stimulation. The present data differ from those reported by Franchimont et al. (3) in hypogonadal males who observed a significant increase in PRL response to TRH. The difference is, however, self-explanatory in view of the levels of circulating gonadal steroids. In this regard, E2 levels seem to ptay a crucial role in the male, like in the female (14).
9. Franchimont P., Dourcy S., Legros J.J., Reuter A., VrindtsGevaert Y., v. Cauwenberge J.R., Remacle P., Gaspard U., Colin C. Dosage de la prolactine dans les conditions normales et pathologiques. Ann. Endocrinol. (Paris), 37: 127, 1976. 10. Luisi M .. Kicovic P.M., Franchi F. Effects of estradiol decanoate in ovariectomized women. J. Endoc;rinol. Invest 2: 101, 1978. 11. Luisi M, Franchi F., Menchini GF, Barletta D., Fassorra C., Ciardella F., Gagliardi G. Radioimmunoassay for plasma testosterone. Steroids Lipidis Res. 4: 213, 1973.
REFERENCES 1. Franchi F., Luisi M.. Kicovic P.M. Pilot clinical and radioimmunological evaluation of the effects of orally administered testosterone undecanoate in hypogonadal men. Proc. 1st Intern. Congr. Androl., Barcelona (1976), Intern. J. Androl., (Suppl.) 1, 1978 (in press).
12. Ciardella F., Galli P., Sgrilli R., Franchi F., Catarsi A.L., Birindelli R., Luisi M. Radioimmunoassay for plasma prolactin in humans. Boil. Soc. Med. Chir. 4: 219, 1976. 13. Franchimont P., Demoulin A., Bourguignon J,P. Clinical use of LH-RH Test as a diagnostic tool. Horm. Res. 6: 177, 1975.
2. Metelkov Z., Rocic B., Skrabalo Z. Treatment of hypogonadal male patients with oral testosterone undecanoate: preliminary communication. Proc. 1st Intern. Congr. An.drol., Barcelona (1976).lntem. J. Androl., (Suppl.) 1, 1978 (in press).
14. Kicovic P.M., Franchi M., Krempl S., Luisi M. Correlation between circulating estradiol and PRL response to TRH in men. Vth ESCO, Venezia, 1978 (submitted for presentation).
3. Franchimont P., Kicovic P.M., Mattei A., Roulier R.
361
SHORT COMMUNICATION
Circulating prolactin and its response to TRH following administration of testosterone undecanoate in normal men 1 P.M. Kicovic*, M. Luisi**, F. Franchi** and S. Krempl* *Scientific Development Group, Medical U nit. Organon, Oss, Holland and **Endocrine Unit of C.N.R., 1 st Medical Clinic, University Hospital, Pisa, Italy
ABSTRACT. To investigate the effect of orally administered testosterone undecanoate (TU) on circulating prolactin (PRL) and PRL response to TRH stimulation, 8 eugonadal male volunteers, aged 19-30, presenting with normal plasma levels of FSH, LH, testosterone (T), estradiol (E2) and PRL, were given 120 mg/day of TU for 6 days. Plasma PRL levels were measured daily during the pre-treatment phase (3 days), treatment phase (6 days) and post-treatment phase (3 days) by radioimmunoassay. The TRH Test (200 I1g iv) was done on the 3rd day of the pretreatment phase and on the treatment phase. No sig nficant changes in circulating PRL levels or in PRL response to TRH stimulation were observed. Plasma T and E2 levels showed a slight, but not significant tendency to increase, while gonadotropin levels remained unchanged. INTRODUCTION
MATERIALS AND METHODS
Several recent studies (1-4) have shown that orally administered testosterone undecanoate (TU) is an effective form of substitution therapy in male hypogoladal patients. In hypergonadotropic hypogonadal ,11ales TU significantly suppressed the levels of circulating FSH and LH, while in hypogonadotropic hypogonadal males both gonadotropins were increased (3). In the same study a normalization of prolactin (PRL) response to TRH stimulation was observed in patients with poor PRL response prior to the TU therapy. In normal men, however, TU did not alter the functional capacity of the gonadotropic area of the hypothalamic-pituitary axis, as assessed by means of the LHRH (5) and clomiphene tests (6). All these observations suggested that TU displays interesting properties with regard to hypothalamic-pituitary function. Evidence that estrogens promote pituitary PRL secretion has recently been well documented (710). To our knowledge, no data on effects of exogenously administered andr.ogens on the pituitary PRL secretion in eugonadal men are available. This study examines whether changes in circulating PRL and PRL response to TRH occur during administration of oral TU to normal men.
Eight normal men between the ages of 19 and 30 agreed to partecipate in this study and served as volunteers. None of the subjects had any illness or took any medication prior to, or during, the present study. Physical examination and X-ray of sella turcica did not reveal abnormalities. Basal plasma FSH, LH, testosterone (T), estradiol (E2) and PRL levels in all subjects were within the normal ranges. Venous blood samples for determination of plasm'a PRL levels were obtained daily during the pretreatment phase (3 days), during the treatment phase (120 mg/ day of TU, given as 3x1 capsule of 40 mg at meals, for 6 days), and during the post-treatment phase (3 days), always between 08:00 and 08:30 h. The TRH test was performed twice: on the 3rd day of the pretreatment phase and on the 6th day of the treatment phase, in the morning after an overnight fast. Synthetic TRH (200 Jig) was administered intravenously as a bolus injection at time 0 through an indwelling scalp vein needle. Blood was sampled at -15, 0, 10, 20, 30, 60 and 120 minutes for determination of the plasma PRL concentrations. On the 6th day of the treatment phase plasma samples for determination of FSH, LH, T and E2 levels were also obtained. Each blood sample was immediately centrifuged, and the plasma was separated and frozen at -20 C until analized.
1 Supported. in part. by the grant no. 76.0t 527.04/11 511 30 from the Consiglio Nazionale delle Ricerche (Roma)
Plasma FSH and LH were measured by using RIAmat-FSH (5423 Byk-Mallinkrodt) and RIA-mat-LH (5263 Byk-Mallinkrodt), respectively. The amounts of FSH and LH were calculated relative to MRC Standards 68/39 and 68/40, respectively, and expressed
Key-words: Testosterone undecanoate, plasma PRL. TRH test, normal men.
Correpondence: Prof. P.M. Kicovic • Medical Unit. SDG. Organon. Oss. Holland Received May 30. 1978; accepted August 31. 1978
359
P.M. Kicovic, M. Luisi, F. Franchi, and S. Krempl
Table 1 - Plasma hormone levels (mean after TU medica tion (no. = 8).
Testosterone LH (nmol / I) 1 (mU / ml)
FSH (mU/ml)
Before TU 2.8±0.9 6.2 ± 1.2 2.3 ± 0.7 3 6.0 ± 09 3
After TU 1 _
1 nmol /l "" 288
± SO) before and
18.7± 3.1
All assays were carried out in duplicate, at the same time and with the same batches of reagents. Data were analysed by means of the t test of mean differences. For PRL the value during treatment of post-treatment minus the pretreatment value (calculated as an average of 3 pretreatment values) was used as variable value for the t test. Calculation of cumulative responses of PRL to TRH was done according to Franchimont et al. (13).
Estradiol (pmol / I) 2 147.4±20.8
20.6 ± 3.0 3 154.4 ± 18.9 3
ng / l00 ml
2 _ 1 pmoi/l "" 0.27 pg /m!.
3 - NS.
RESULTS Plasma FSH , LH , T and E2levels, measured before and after the medication with TU, are shown in Table 1. As can be seen, FSH and LH levels remained unchanged, while both T and E2 levels slightly increased. The changes did not reach significant levels. Mean (± SO) plasma PRL levels, estimated at baseline
in mlU / ml. Plasma T was measured as previously described by Luisi et al. (11). RIA-kit (CEA-IRESORIN) was used for the determination of plasma E2. Plasma PRL was estimated according to Ciardella et al. (12), using Biodata kit. Table 2 - Mean (± SO) circulating PRL at baseline (n o. = 8)
Treatment
Pre-treatment
Phase
-2 8.4 ± 2.2
Day PRL (ng/ml)
-1
o
8.6 ± 2.1
8.0 ± 1.9
84 ± 2.3
Post-treatment
1
2
3
4
5
6
8.3 ±1 .9
7.9 ± 1.6
8.5 ±2.2
8.7 ± 2.1
9.2 ± 2.1
1 9.0 ± 2.3
1
2
3
8.6 ± 1.9
8.7 2.2
±
1 No stat isti ca lly significant differences were foun d.
1500
48
Cumulative response
TRH.200ug 40
:" '
-- -at -
1000
32
--..
E --..
0>
c:
....i
, ,,,
.t: N
...
0>
c:
24
C :>
a:
'" ..:r
0-
Q)
..........
16
500
8
,
- 15 0 Minutes
,
10
20
30
120
60
beforeTU
after TU
Fig 1 - Mean (± SO) PRL release and cumulative response to 200 I1g of TRH before ( - ) and after ( - - - ) TU medicatIOn (no
360
= 8)
Testosterone undecanoate, PRL response to TRH
during the pretreatment, treatment and post-treatment phases, are given in Table 2. Mean plasma PRL tended to increase during treatment, but the differences were not significant. Figure 1 illustrates mean (± SO) plasma PRL,concentration during the TRH test performed on the 3rd day of the pretreatment phase and on the 6th day of the treatment phase. Plasma PRL cumulative responses (mean ± SO) are also presented. Mean peak PRL values were recorded 20 minutes after TRH administration in both tests. Before TU medication PRL rose from 7.9 ± 1.8 to 32.5 ± 9.1 ng/ml. On the 6th treatment day PRL rose from 9.1 ± 2.0 to 37.4 ± 8.8 ng/ml. After having reached peak values at 20 minutes, PRL levels declined progressively to the levels slighlty higher than pretreatment ones at the and of both tests. Cumulative responses before end after TU medication also showed minor differences, i.e. 1012 ± 350 and 1058 ± 237 ng/2h, respectively.
Effects of oral testosterone undecanoate in hypogonadal male patients. Acta Endocrinol. (Kbh) (Suppl) 212: 118, 1977. 4. Mies R., Krempl S. Effects of oral testosterone undecanoate on plasma hormones and clinical symptomatology in hypo gonadal male patients Acta Endocrinol. (Kbh) (Suppl) 212: 119, 1977 5. Mies R., Kicovic P.M. Effects of testosterone undecanoate administration on LH ad FSH response during the LH-RH Test in healthy male volunteers. Andrologia 9( 3): 233, 1977. 6. Luisi M., Eliasson R., Kicovic P.M., Franchi F., Alicicco E. Hypothalamic-pituitary responsiveness to the clomiphene stimulation during a placebo controlled study of testosterone undecanoate therapy in normal men. Proc. Intern. Symp. Rec. Progr. Androl., L'Aquila (1977), Academic Press, London-New York, 1978 (in press). 7. Frantz A.G., Kleinberg D.L., Noel G.L. Studies on prolactin in man. Recent Progr. Horm. Res. 28: 527, 1972.
DISCUSSION
8. Yen SS.C., Ehara Y., Siler T.M. Augmentation of prolactin secretion by estrogen in hypogonadal women. J. Clin. Invest. 53: 652,1974.
The present study demonstrates that oral TU, given in a dose of 120 mg/day for 6 days to normal male volunteers, does not influence either circulating PRL or its response to TRH stimulation. The present data differ from those reported by Franchimont et al. (3) in hypogonadal males who observed a significant increase in PRL response to TRH. The difference is, however, self-explanatory in view of the levels of circulating gonadal steroids. In this regard, E2 levels seem to ptay a crucial role in the male, like in the female (14).
9. Franchimont P., Dourcy S., Legros J.J., Reuter A., VrindtsGevaert Y., v. Cauwenberge J.R., Remacle P., Gaspard U., Colin C. Dosage de la prolactine dans les conditions normales et pathologiques. Ann. Endocrinol. (Paris), 37: 127, 1976. 10. Luisi M .. Kicovic P.M., Franchi F. Effects of estradiol decanoate in ovariectomized women. J. Endoc;rinol. Invest 2: 101, 1978. 11. Luisi M, Franchi F., Menchini GF, Barletta D., Fassorra C., Ciardella F., Gagliardi G. Radioimmunoassay for plasma testosterone. Steroids Lipidis Res. 4: 213, 1973.
REFERENCES 1. Franchi F., Luisi M.. Kicovic P.M. Pilot clinical and radioimmunological evaluation of the effects of orally administered testosterone undecanoate in hypogonadal men. Proc. 1st Intern. Congr. Androl., Barcelona (1976), Intern. J. Androl., (Suppl.) 1, 1978 (in press).
12. Ciardella F., Galli P., Sgrilli R., Franchi F., Catarsi A.L., Birindelli R., Luisi M. Radioimmunoassay for plasma prolactin in humans. Boil. Soc. Med. Chir. 4: 219, 1976. 13. Franchimont P., Demoulin A., Bourguignon J,P. Clinical use of LH-RH Test as a diagnostic tool. Horm. Res. 6: 177, 1975.
2. Metelkov Z., Rocic B., Skrabalo Z. Treatment of hypogonadal male patients with oral testosterone undecanoate: preliminary communication. Proc. 1st Intern. Congr. An.drol., Barcelona (1976).lntem. J. Androl., (Suppl.) 1, 1978 (in press).
14. Kicovic P.M., Franchi M., Krempl S., Luisi M. Correlation between circulating estradiol and PRL response to TRH in men. Vth ESCO, Venezia, 1978 (submitted for presentation).
3. Franchimont P., Kicovic P.M., Mattei A., Roulier R.
361
