FERTILITY AND STERILITY Copyright© 1975 The American Fertility Society
Vol. 26, No.4, April 1975 Printed in U.S A.
PLASMA TESTOSTERONE RESPONSE TO SHORT-TERM HUMAN CHORIONIC GONADOTROPIN ADMINISTRATION IN MEN WITH FOLLICLE-STIMULATING HORMONE SUPPRESSED BY EXOGENOUS ESTROGEN EDWARD 0. REITER, M.D.,*
AND
HOWARD E. KULIN, M.D.t
Reproduction Research Branch, National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, Maryland 20014
A role for follicle-stimulating hormone (FSH) in Leydig cell function has not been clearly demonstrated in men. Long-term and short-term in vivo experiments in the rat have indicated that FSH plays a significant role in androgen secretion.L2 In vitro studies on rabbit testes have also shown that FSH augments luteinizing hormone (LH)-induced testosterone production. 3 •4 Recently, Sizonenko et al 5 suggested that endogenous FSH levels in prepubertal and early pubertal boys may influence the testicular response to exogenous human chorionic gonadotropin (HCG). The present studies were designed to investigate further in men the role of FSH in testosterone production by testes. MATERIALS AND METHODS
Nine adult men were studied as normal volunteers in the Clinical Center of the National Institutes of Health. Data were also obtained from a 14-yearold early pubertal boy, otherwise endocrinologically normal, who was under examination for short stature. The adult males were divided into two series (Table 1). Series 1 consisted of
four men who had their gonadal function assessed by HCG administration 6 both before and during estrogen-induced reduction in FSH levels. Series 2 included these four subjects plus five additional men, three of whom were given HCG alone, and two of whom were given HCG and estrogen. Protocol 1. HCG (4,000 IU/day) was administered intramuscularly for four days (Fig. 1). Control gonadotropin levels were determined in three to nine blood and 24-hour urine specimens, while plasma testosterone was measured in two to four control samples. FSH and testosterone were again measured on days 4 to 6. Protocol 2. HCG (4,000 IU/day) was administered intramuscularly from days 8 to 11 of an 11-day treatment course during which 40 to 50 J.Lg of ethinyl estradiol was ingested daily (Fig. 1). This dose range of ethinyl estradiol suppresses FSH production by approximately 50%. 7
Received June 12, 1974. *Present address and reprint requests: Department of Pediatrics, University of South Florida College of Medicine, All Children's Hospital, St. Petersburg, Florida 33701. tPresent address: Department of Pediatrics, Milton S. Hershey Medical Center, Pennsylvania State University, College of Medicine, Hershey, Penn· sylvania 17033.
340
TABLE 1. Groups of Men Studied and Treatment Given Series 1 (paired comparisons)
Series 2 (pooled data)
Subject
HCG
HCG + estrogen
HCG
HCG + estrogen
1
X
X
X
X
2 3 4 5
X
X
X
X
X
X
X
X
X
X
X
X
X X X
6 7 8 9 Total
X X
4
4
7
6
Vol. 26, No. 4
PLASMA TESTOSTERONE RESPONSE TO HCG
341
0.5 to 0.6 miU/tube. Specimens which precipitated more than 80% of the trace Protocol 1: HCG without Estrogen material when 300 ~-tl was added to the 1-HCG•I assay were reported as less than 2 miU/ml; I I I I I I such results were considered as 2.0 control 1 2 3 4 5 6 days miU/ml for statistical purposes. The Protocol 2: HCG with Estrogen lower limit of detection for urinary FSH 1-Ethinyl Estradiol-~ was approximately 0.06 to 0.08 IU/day. 10 I•HCG-. All urinary samples were evaluated in control I I I I I I I I I I I I I I 2 3 4 5 6 7 8 9 10 II 12 13 the radioimmunoassay at two or more days dose intervals. l-17.tlE2.-I•HcG-i Protocol 3: Plasma testosterone was measured by Patient R.G. a radio ligand assay .11 All FSH and testoI I I I I I I I I control 123456789 sterone samples from a given individual days were measured on the same assay. The FIG. 1. Study protocol for HCG tests without unpaired Student's t test was used for exogenous estrogen and during estrogen adminisstatistical comparisons. tration. STUDY PROTOCOLS
One man (subject 1) received 16 mg/day of oral ethinyl estradiol for the 11-day period. Control hormonal measurements were made as in protocol! with additional samples obtained on days 5 to 7 (pre-HCG) and days 11 to 13 (post-HCG). The HCG tests with and without estrogen were separated by three to five weeks in each subject. Protocol 3. The early pubertal boy, R. G., was studied by protocol3 (Fig. 1). For five days, 17,8-estradiol (15 ~-tg/kg/day) was administered intramuscularly to suppress FSH production. HCG (2,000 IU) was given for three days (days 6 to 8). Samples were collected during a four-day control period and for the following five days of the treatment protocol. Assays. Plasma FSH and LH and urinary FSH with extracted kaolin acetone were measured by double-antibody radioimmunoassay using the second international reference preparation of human menopausal gonadotropin (2nd IRP, HMG) for dose interpolation. 8- 10 In our laboratory, 1 miU of plasma FSH and LH activity of this HMG is immunoreactively equivalent to 30 ng and 3.9 ng, respectively, of the pituitary standard LER-907. The lower limit of detection in our plasma FSH and LH assays was approximately
RESULTS
Series 1 (Paired Comparisons). The results from the four men who received HCG alone (protocol!) and during estrogen treatment (protocol 2) are presented in Table 1. In series 1 where each individual served as his own control, the pre-HCG hormone values, as well as the levels before estrogen, were pooled and considered to represent the basal state (pre-HCG, Table 2). As noted, one of the men (subject 1, Table 1) received a higher estrogen suppressive regimen; as a result, his urinary FSH excretion decreased to a greater degree, and these data were not included in the group calculations. Significant suppression of plasma and urinary FSH and plasma testosterone occurred by days 5 through 7 of the estrogen treatment period. Plasma LH levels were also significantly reduced {P
Vol. 26, No.4, April 1975 Printed in U.S A.
PLASMA TESTOSTERONE RESPONSE TO SHORT-TERM HUMAN CHORIONIC GONADOTROPIN ADMINISTRATION IN MEN WITH FOLLICLE-STIMULATING HORMONE SUPPRESSED BY EXOGENOUS ESTROGEN EDWARD 0. REITER, M.D.,*
AND
HOWARD E. KULIN, M.D.t
Reproduction Research Branch, National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, Maryland 20014
A role for follicle-stimulating hormone (FSH) in Leydig cell function has not been clearly demonstrated in men. Long-term and short-term in vivo experiments in the rat have indicated that FSH plays a significant role in androgen secretion.L2 In vitro studies on rabbit testes have also shown that FSH augments luteinizing hormone (LH)-induced testosterone production. 3 •4 Recently, Sizonenko et al 5 suggested that endogenous FSH levels in prepubertal and early pubertal boys may influence the testicular response to exogenous human chorionic gonadotropin (HCG). The present studies were designed to investigate further in men the role of FSH in testosterone production by testes. MATERIALS AND METHODS
Nine adult men were studied as normal volunteers in the Clinical Center of the National Institutes of Health. Data were also obtained from a 14-yearold early pubertal boy, otherwise endocrinologically normal, who was under examination for short stature. The adult males were divided into two series (Table 1). Series 1 consisted of
four men who had their gonadal function assessed by HCG administration 6 both before and during estrogen-induced reduction in FSH levels. Series 2 included these four subjects plus five additional men, three of whom were given HCG alone, and two of whom were given HCG and estrogen. Protocol 1. HCG (4,000 IU/day) was administered intramuscularly for four days (Fig. 1). Control gonadotropin levels were determined in three to nine blood and 24-hour urine specimens, while plasma testosterone was measured in two to four control samples. FSH and testosterone were again measured on days 4 to 6. Protocol 2. HCG (4,000 IU/day) was administered intramuscularly from days 8 to 11 of an 11-day treatment course during which 40 to 50 J.Lg of ethinyl estradiol was ingested daily (Fig. 1). This dose range of ethinyl estradiol suppresses FSH production by approximately 50%. 7
Received June 12, 1974. *Present address and reprint requests: Department of Pediatrics, University of South Florida College of Medicine, All Children's Hospital, St. Petersburg, Florida 33701. tPresent address: Department of Pediatrics, Milton S. Hershey Medical Center, Pennsylvania State University, College of Medicine, Hershey, Penn· sylvania 17033.
340
TABLE 1. Groups of Men Studied and Treatment Given Series 1 (paired comparisons)
Series 2 (pooled data)
Subject
HCG
HCG + estrogen
HCG
HCG + estrogen
1
X
X
X
X
2 3 4 5
X
X
X
X
X
X
X
X
X
X
X
X
X X X
6 7 8 9 Total
X X
4
4
7
6
Vol. 26, No. 4
PLASMA TESTOSTERONE RESPONSE TO HCG
341
0.5 to 0.6 miU/tube. Specimens which precipitated more than 80% of the trace Protocol 1: HCG without Estrogen material when 300 ~-tl was added to the 1-HCG•I assay were reported as less than 2 miU/ml; I I I I I I such results were considered as 2.0 control 1 2 3 4 5 6 days miU/ml for statistical purposes. The Protocol 2: HCG with Estrogen lower limit of detection for urinary FSH 1-Ethinyl Estradiol-~ was approximately 0.06 to 0.08 IU/day. 10 I•HCG-. All urinary samples were evaluated in control I I I I I I I I I I I I I I 2 3 4 5 6 7 8 9 10 II 12 13 the radioimmunoassay at two or more days dose intervals. l-17.tlE2.-I•HcG-i Protocol 3: Plasma testosterone was measured by Patient R.G. a radio ligand assay .11 All FSH and testoI I I I I I I I I control 123456789 sterone samples from a given individual days were measured on the same assay. The FIG. 1. Study protocol for HCG tests without unpaired Student's t test was used for exogenous estrogen and during estrogen adminisstatistical comparisons. tration. STUDY PROTOCOLS
One man (subject 1) received 16 mg/day of oral ethinyl estradiol for the 11-day period. Control hormonal measurements were made as in protocol! with additional samples obtained on days 5 to 7 (pre-HCG) and days 11 to 13 (post-HCG). The HCG tests with and without estrogen were separated by three to five weeks in each subject. Protocol 3. The early pubertal boy, R. G., was studied by protocol3 (Fig. 1). For five days, 17,8-estradiol (15 ~-tg/kg/day) was administered intramuscularly to suppress FSH production. HCG (2,000 IU) was given for three days (days 6 to 8). Samples were collected during a four-day control period and for the following five days of the treatment protocol. Assays. Plasma FSH and LH and urinary FSH with extracted kaolin acetone were measured by double-antibody radioimmunoassay using the second international reference preparation of human menopausal gonadotropin (2nd IRP, HMG) for dose interpolation. 8- 10 In our laboratory, 1 miU of plasma FSH and LH activity of this HMG is immunoreactively equivalent to 30 ng and 3.9 ng, respectively, of the pituitary standard LER-907. The lower limit of detection in our plasma FSH and LH assays was approximately
RESULTS
Series 1 (Paired Comparisons). The results from the four men who received HCG alone (protocol!) and during estrogen treatment (protocol 2) are presented in Table 1. In series 1 where each individual served as his own control, the pre-HCG hormone values, as well as the levels before estrogen, were pooled and considered to represent the basal state (pre-HCG, Table 2). As noted, one of the men (subject 1, Table 1) received a higher estrogen suppressive regimen; as a result, his urinary FSH excretion decreased to a greater degree, and these data were not included in the group calculations. Significant suppression of plasma and urinary FSH and plasma testosterone occurred by days 5 through 7 of the estrogen treatment period. Plasma LH levels were also significantly reduced {P
