Long-term Effects of Vasectomy on Pituitary-Gonadal Function in Man MADAN M. VARMA,1 REJIV R. VARMA,2 ANN J. JOHANSON,3 AVINOAM KOWARSKI,1 AND CLAUDE J. MIGEON 1 1
Department of Pediatrics, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; 2 Patna Medical College, Patna, Bihar, India; 3 Department of Pediatrics, University of Virginia Medical School, Charlottesville, Virginia 22901 ± 39.5 (SE) ng/100 ml; FSH = 15.09 ± 2.18 (SE) mlU/ml; LH = 10.03 ± 1.13 (SE) mlU/ml and TB = 92.99 ± 0.285 (SE) % binding was detected in any group of the vasectomized men in any of the parameters studied. (J Clin Endocrinol Metab 40: 868, 1975)
ABSTRACT. Plasma concentrations of testosterone (T), follicle stimulating hormone (FSH), and luteinizing hormone (LH) and percent binding of T to plasma protein (TB) were studied in 16 normal fertile men and in 81 men who had undergone vasectomy from 1 to 5 yr earlier. No significant difference from the control values to T = 582
V
ASECTOMY is widely used around the world as an anti-fertility measure. In India a national program of vasectomy has been promoted for many years as a means of control of population. Yet, there has been little study on the long term effects of this surgical procedure in man, with regard to endocrine function. The propriety of a continued and widespread use of vasectomy in spite of a lack of information regarding its long-term effects has been debated from an ethical point of view (1,2). We, therefore, undertook a study of the long-term effect of vasectomy on pituitary-gonadal function in man, particularly with regard to testosterone and gonadotropin plasma levels and binding of testosterone by plasma protein in a control group of apparently normal, healthy, fertile men who had not undergone vasectomy and groups of men who had undergone vasectomy for periods varying from 1 to 5 yr earlier. Materials and Methods The subjects of this study were chosen from India because of the long standing public program of vasectomy in that country as part of Received September 6, 1974. Supported by U.S. Public Health Service Grants AM-00180-23, HD-06284-03 and 5-K6-AM-21855.
the nation's population control program. Blood was obtained from the antecubital vein of 81 vasectomized men between 30-45 yr of age. Of these individuals 28 had undergone the operation 1 to 2 yr earlier, 21 from 2 to 3 yr ago, 20 from 3 to 4 yr before, and 12 between 4 to 5 yr earlier. All subjects were from the district of Champaran in the State of Bihar. Dates on which they were vasectomized were obtained from the records of the local family planning centers. In addition, blood was collected similarly from 16 men who appeared normal on physical examination, had not undergone vasectomy, were fathers of several children in the recent past, and belong to the same geographical area, socio-economic level, and age group as the men who had undergone vasectomy. All blood collections were made between 9:00 AM and 12:00 noon and kept in heparinized tubes. Plasma was separated on the spot, stored frozen and brought to Baltimore on dry ice. Plasma concentrations of gonadotropins, FSH and LH, and testosterone were measured by radioimmunoassay and the binding of testosterone to plasma protein was estimated by the method of equilibrium dialysis described elsewhere (3). Measurement of testosterone: Approximately 1400 cpm of 3H-testosterone (SA 91.0 Ci/mmol) was added to 1 ml of plasma. The samples were extracted thrice with 10 ml of ether (Mallinckrodt, Anesthesia grade) and subsequently washed with 0.1N HC1 and water. The extracted steroid was chromatographed on Whatman paper No. 2 in a benzene:heptane:methanol:water (166.6:333.3:400:100) system for 3 h at 37 C 868
The Endocrine Society. Downloaded from press.endocrine.org by [${individualUser.displayName}] on 16 November 2015. at 21:47 For personal use only. No other uses without permission. . All rights reserved.
869
VASECTOMY EFFECTS ON PITUITARY GONADAL FUNCTION
600-
xm a
—
!
O
T
T
T T
U
ONE
O 400K UJ 1CS)
25 8 0 -
o
1-
10) UJ
o
n
1
T
1to
200< < J o.
T
O
2 O
The concentration of the hormones and the percent binding of testosterone observed in the plasma of individuals of the different groups is shown in Figs. 1 and 2. The mean plasma concentration of testosterone, FSH and LH found in the control group of normal, fertile men was 582 ± 39.5 (SE) ng/100 ml, 15.09 ± 2.18 (SE) mlU/ml, and 10.3 ± 1.13 (SE) mlU/ml respectively. No significant difference could be detected in the plasma concentrations of these hormones in any group of vasectomized men studied as determined by the Student's t test (P > 0.1). The level of the hormones remained unaffected by the length of time following surgery. No significant difference between the percentage binding of testosterone to plasma protein in the control and any of the
(iS.E.)
UJ U) •H
Results
% BINDING
after an initial half-hour period of equilibration. The zone on the paper strip corresponding to standard testosterone spot was eluted with methanol. The eluate was dried and redissolved in 1.5 ml of methanol (spectroquality). Aliquots of 100, 200, and 300 fx\ of the redissolved testosterone were used for radioimmunoassay. The antiserum used was developed in our laboratory in female New Zealand white rabbits against testosterone-3-oxime conjugated to bovine serum albumin. The dilution of the antiserum used was 1:2,500. The interassay coefficient of variation, based on successive determination of testosterone concentration in 1 ml of plasma in each assay from a pool of male plasma was found to be 10.5%. Blank values, as determined on eluates of a portion of the paper corresponding to the testosterone zone and in an extract of 2 ml of water, consistently read less than 50 pg on the standard curve. FSH and LH concentrations were determined according to the method described earlier (4,5).
UJ
:
m
1-
16 C
28 I
21
20
IE
UL
12 TZ
16 n=
C
28 I
21
n
i 20
12
HE
FIG. 1. Plasma testosterone concentrations and its percentage binding in normal men (C) and men who had undergone vasectomy 1-2 yr earlier (I), 2-3 yr earlier (II), 3-4 yr earlier (III), and 4-5 yr earlier (IV). Brackets denote standard errors of the mean; the number of individuals in each group is indicated at the bottom.
The Endocrine Society. Downloaded from press.endocrine.org by [${individualUser.displayName}] on 16 November 2015. at 21:47 For personal use only. No other uses without permission. . All rights reserved.
LJ CO
+1 2 5 -
D H E
JCE & M • 1975 Vol 40 • No 5
VARMA ET AL.
870
25-
T
15-
H
E 15-
I m u. 5 to
Department of Pediatrics, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; 2 Patna Medical College, Patna, Bihar, India; 3 Department of Pediatrics, University of Virginia Medical School, Charlottesville, Virginia 22901 ± 39.5 (SE) ng/100 ml; FSH = 15.09 ± 2.18 (SE) mlU/ml; LH = 10.03 ± 1.13 (SE) mlU/ml and TB = 92.99 ± 0.285 (SE) % binding was detected in any group of the vasectomized men in any of the parameters studied. (J Clin Endocrinol Metab 40: 868, 1975)
ABSTRACT. Plasma concentrations of testosterone (T), follicle stimulating hormone (FSH), and luteinizing hormone (LH) and percent binding of T to plasma protein (TB) were studied in 16 normal fertile men and in 81 men who had undergone vasectomy from 1 to 5 yr earlier. No significant difference from the control values to T = 582
V
ASECTOMY is widely used around the world as an anti-fertility measure. In India a national program of vasectomy has been promoted for many years as a means of control of population. Yet, there has been little study on the long term effects of this surgical procedure in man, with regard to endocrine function. The propriety of a continued and widespread use of vasectomy in spite of a lack of information regarding its long-term effects has been debated from an ethical point of view (1,2). We, therefore, undertook a study of the long-term effect of vasectomy on pituitary-gonadal function in man, particularly with regard to testosterone and gonadotropin plasma levels and binding of testosterone by plasma protein in a control group of apparently normal, healthy, fertile men who had not undergone vasectomy and groups of men who had undergone vasectomy for periods varying from 1 to 5 yr earlier. Materials and Methods The subjects of this study were chosen from India because of the long standing public program of vasectomy in that country as part of Received September 6, 1974. Supported by U.S. Public Health Service Grants AM-00180-23, HD-06284-03 and 5-K6-AM-21855.
the nation's population control program. Blood was obtained from the antecubital vein of 81 vasectomized men between 30-45 yr of age. Of these individuals 28 had undergone the operation 1 to 2 yr earlier, 21 from 2 to 3 yr ago, 20 from 3 to 4 yr before, and 12 between 4 to 5 yr earlier. All subjects were from the district of Champaran in the State of Bihar. Dates on which they were vasectomized were obtained from the records of the local family planning centers. In addition, blood was collected similarly from 16 men who appeared normal on physical examination, had not undergone vasectomy, were fathers of several children in the recent past, and belong to the same geographical area, socio-economic level, and age group as the men who had undergone vasectomy. All blood collections were made between 9:00 AM and 12:00 noon and kept in heparinized tubes. Plasma was separated on the spot, stored frozen and brought to Baltimore on dry ice. Plasma concentrations of gonadotropins, FSH and LH, and testosterone were measured by radioimmunoassay and the binding of testosterone to plasma protein was estimated by the method of equilibrium dialysis described elsewhere (3). Measurement of testosterone: Approximately 1400 cpm of 3H-testosterone (SA 91.0 Ci/mmol) was added to 1 ml of plasma. The samples were extracted thrice with 10 ml of ether (Mallinckrodt, Anesthesia grade) and subsequently washed with 0.1N HC1 and water. The extracted steroid was chromatographed on Whatman paper No. 2 in a benzene:heptane:methanol:water (166.6:333.3:400:100) system for 3 h at 37 C 868
The Endocrine Society. Downloaded from press.endocrine.org by [${individualUser.displayName}] on 16 November 2015. at 21:47 For personal use only. No other uses without permission. . All rights reserved.
869
VASECTOMY EFFECTS ON PITUITARY GONADAL FUNCTION
600-
xm a
—
!
O
T
T
T T
U
ONE
O 400K UJ 1CS)
25 8 0 -
o
1-
10) UJ
o
n
1
T
1to
200< < J o.
T
O
2 O
The concentration of the hormones and the percent binding of testosterone observed in the plasma of individuals of the different groups is shown in Figs. 1 and 2. The mean plasma concentration of testosterone, FSH and LH found in the control group of normal, fertile men was 582 ± 39.5 (SE) ng/100 ml, 15.09 ± 2.18 (SE) mlU/ml, and 10.3 ± 1.13 (SE) mlU/ml respectively. No significant difference could be detected in the plasma concentrations of these hormones in any group of vasectomized men studied as determined by the Student's t test (P > 0.1). The level of the hormones remained unaffected by the length of time following surgery. No significant difference between the percentage binding of testosterone to plasma protein in the control and any of the
(iS.E.)
UJ U) •H
Results
% BINDING
after an initial half-hour period of equilibration. The zone on the paper strip corresponding to standard testosterone spot was eluted with methanol. The eluate was dried and redissolved in 1.5 ml of methanol (spectroquality). Aliquots of 100, 200, and 300 fx\ of the redissolved testosterone were used for radioimmunoassay. The antiserum used was developed in our laboratory in female New Zealand white rabbits against testosterone-3-oxime conjugated to bovine serum albumin. The dilution of the antiserum used was 1:2,500. The interassay coefficient of variation, based on successive determination of testosterone concentration in 1 ml of plasma in each assay from a pool of male plasma was found to be 10.5%. Blank values, as determined on eluates of a portion of the paper corresponding to the testosterone zone and in an extract of 2 ml of water, consistently read less than 50 pg on the standard curve. FSH and LH concentrations were determined according to the method described earlier (4,5).
UJ
:
m
1-
16 C
28 I
21
20
IE
UL
12 TZ
16 n=
C
28 I
21
n
i 20
12
HE
FIG. 1. Plasma testosterone concentrations and its percentage binding in normal men (C) and men who had undergone vasectomy 1-2 yr earlier (I), 2-3 yr earlier (II), 3-4 yr earlier (III), and 4-5 yr earlier (IV). Brackets denote standard errors of the mean; the number of individuals in each group is indicated at the bottom.
The Endocrine Society. Downloaded from press.endocrine.org by [${individualUser.displayName}] on 16 November 2015. at 21:47 For personal use only. No other uses without permission. . All rights reserved.
LJ CO
+1 2 5 -
D H E
JCE & M • 1975 Vol 40 • No 5
VARMA ET AL.
870
25-
T
15-
H
E 15-
I m u. 5 to
