Influence of Sexual Stimulation and the Administration of Human Chorionic Gonadotrophin on Plasma Testosterone Levels in Dogs

SUMMARY Peripheral plasma testosterone levels in the male rat were increased above control levels 5 min after the first intromission with an oestrous female, or 8–10 min after first contact with the female. The levels remained raised for at least 30 min if copulation was allowed to continue. Intravenous injection of human chorionic gonadotrophin resulted in an increased peripheral concentration of plasma testosterone after 10–15 min and an increase of testosterone content of the testis 5–10 min after injection, indicating that the rat testis has a potential to respond rapidly to gonadotrophin. The results suggested that if the testosterone surge during copulation was gonadotrophin-dependent, it was initiated before the first intromission. Indeed, plasma testosterone levels were raised in male rats 5 min after being placed in the proximity of oestrous females but not allowed physical contact.

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Effect of intraventricular injection of 5,6-dihydroxytryptamine on spermatogenesis and plasma testosterone levels in the rat

Journal of Endocrinology ◽

10.1677/joe.0.1060395 ◽

1985 ◽

Vol 106 (3) ◽

pp. 395-NP ◽

Cited By ~ 5

Author(s):

T. K. Das ◽

R. Mazumder ◽

N. M. Biswas

Keyword(s):

Quantitative Evaluation ◽

Wistar Rats ◽

Chorionic Gonadotrophin ◽

Human Chorionic Gonadotrophin ◽

Seminiferous Epithelium ◽

Intraventricular Injection ◽

Plasma Testosterone ◽

Testosterone Levels ◽

Testicular Steroidogenesis

ABSTRACT Quantitative evaluation of spermatogenesis at stage VII of the cycle of the seminiferous epithelium and radioimmunoassay of plasma testosterone were performed in adult Wistar rats after intraventricular injection of 5,6-dihydroxytryptamine (5,6-DHT). The rats were killed 2, 10 and 21 days after injection. Brain 5-hydroxytryptamine (5-HT) and plasma testosterone levels were found to be significantly lower in all rats treated with 5,6-DHT. A significant reduction in step 7 spermatid count was also observed after 10 and 21 days. Supplementation with human chorionic gonadotrophin for 21 days in rats injected with 5,6-DHT partially prevented the step 7 spermatid degeneration and increased testosterone levels without producing any effect on brain concentrations of 5-HT. These results suggest that changes in testicular steroidogenesis and spermatogenesis are secondary to pituitary gonadotrophin release which, in turn, is under the influence of brain 5-HT neurones. J. Endocr. (1985) 106, 395–400

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EFFECT OF GLUCOCORTICOIDS ON PLASMA TESTOSTERONE IN MEN

Acta Endocrinologica ◽

10.1530/acta.0.0890126 ◽

1978 ◽

Vol 89 (1) ◽

pp. 126-131 ◽

Cited By ~ 60

Author(s):

G. Schaison ◽

F. Durand ◽

I. Mowszowicz

Keyword(s):

Chorionic Gonadotrophin ◽

Human Chorionic Gonadotrophin ◽

Plasma Testosterone ◽

Acth Stimulation ◽

Testosterone Levels ◽

Before And After ◽

The Mean ◽

Normal Men ◽

Lh Secretion ◽

Dexamethasone Suppression

ABSTRACT ACTH decreases plasma testosterone levels in men. The aim of this study was to assess the part played by the glucocorticoids in this effect, and the mechanism of their action. Plasma androstenedione, testosterone, cortisol and LH were measured in 8 normal men, before and after the following tests: ACTH stimulation (2 mg im), metyrapone administration (500 mg/every 4 h/6 times) and dexamethasone suppression (8 mg/day/3 days). In addition, androstenedione and testosterone were evaluated under human chorionic gonadotrophin (5000 IU HCG/day/3 days) before and after dexamethasone suppression (8 mg/day/6 days). In all patients, ACTH decreased plasma testosterone from 5.87 ± 1.59 (sd) ng/ml to 3.06 ± 0.8 (sd) ng/ml (P < 0.001). In contrast, after metyrapone, the mean plasma testosterone was increased to 6.98 ± 1.75 (sd) ng/ml. This increase, though not statistically significant, was observed in all patients but one. Both tests resulted in a significant increase of plasma androstenedione (P < 0.01 and P < 0.001, respectively). Dexamethasone suppressed both testosterone and androstenedione levels. None of the three tests had a significant effect on the LH concentration. HCG injection increased the mean plasma testosterone to 11.46 ± 2.80 ng/ml. Dexamethasone significantly depressed (P < 0.01) the testosterone response to HCG. These data are consistent with the following conclusions: 1) The decrease of plasma testosterone levels, observed in men after ACTH administration, is not observed after metyrapone induced ACTH increase. This confirms that it is related to cortisol levels rather than to ACTH itself. 2) Glucocorticoids act directly on testicular biosynthesis since they do not induce any change in LH secretion and since dexamethasone reduces testosterone response to HCG.

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Testosterone Response of Cryptorchid and Hypophysectomized Rats to Human Chorionic Gonadotrophin (hCG) Stimulation

Australian Journal of Biological Sciences ◽

10.1071/bi9850445 ◽

1985 ◽

Vol 38 (4) ◽

pp. 445 ◽

Cited By ~ 1

Author(s):

Y M Hodgson ◽

DM de Kretser

Keyword(s):

Single Injection ◽

Serum Testosterone ◽

Chorionic Gonadotrophin ◽

Human Chorionic Gonadotrophin ◽

Testosterone Levels ◽

Hypophysectomized Rats ◽

Secondary Rise

The testosterone responses to a single injection of HCG (100 i.u.) in hypophysectomized (hypox.), cryptorchid or sham-operated rats were followed over a 5-day period. In sham-operated rats, hCG induced a biphasic rise in serum testosterone, peaks being observed at 2 and 72 h. Reduced testis weights, elevated FSH and LH levels and reduced serum testosterone levels were found after 4 weeks of cryptorchidism, but hCG stimulation resulted in a normal 2 h peak in serum testosterone. However, the secondary rise at 72 h in cryptorchid rats was significantly lower than sham-operated rats.

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THE EFFECT OF INTRAVENOUSLY ADMINISTERED HUMAN CHORIONIC GONADOTROPHIN ON PLASMA LEVELS OF TESTOSTERONE AND 5α-DIHYDROTESTOSTERONE IN NORMAL MALE SUBJECTS

Acta Endocrinologica ◽

10.1530/acta.0.0720615 ◽

1973 ◽

Vol 72 (3) ◽

pp. 615-624 ◽

Cited By ~ 9

Author(s):

W. Maurer ◽

U. Volkwein ◽

J. Tamm

Keyword(s):

Plasma Levels ◽

Initial Phase ◽

Plasma Concentrations ◽

Chorionic Gonadotrophin ◽

Human Chorionic Gonadotrophin ◽

Plasma Testosterone ◽

Normal Male ◽

Peripheral Conversion ◽

Male Subjects

ABSTRACT HCG was infused intravenously into normal male subjects. The doses administered were 500, 100 and 50 IU, respectively. During the initial phase of the infusions the plasma testosterone (T) levels decreased. Thirty minutes after starting the infusion of 500 and 100 IU HCG, respectively, the plasma testosterone increased. Significantly elevated values were observed 60 to 180 minutes after the cessation of HCG administration. The dihydrotestosterone (DHT) concentrations in the plasma showed a varying pattern. On the average this steroid also exhibited an increase in plasma following the HCG administration. From the results no conclusions can be drawn as to the extent to which the plasma concentrations of DHT have been influenced by a secretion from the testes or by a peripheral conversion of T into DHT.

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VIRILIZING ADRENOCORTICAL ADENOMA RESPONSIVE TO GONADOTROPHIN

Acta Endocrinologica ◽

10.1530/acta.0.0780077 ◽

1975 ◽

Vol 78 (1) ◽

pp. 77-85 ◽

Cited By ~ 25

Author(s):

M. Blichert-Toft ◽

H. Vejlsted ◽

H. Kehlet ◽

R. Albrechtsen

Keyword(s):

Young Female ◽

Chorionic Gonadotrophin ◽

Human Chorionic Gonadotrophin ◽

Adrenocortical Function ◽

Plasma Testosterone ◽

Adrenocortical Adenoma ◽

Androgen Excess ◽

Pronounced Increase ◽

Steroid Excretion ◽

Trophic Hormones

ABSTRACT A virilizing adrenocortical adenoma was demonstrated in a young female. Urinary 17-ketosteroid excretion and subfractions, plasma testosterone level and urinary 17-ketogenic steroid excretion were markedly increased. Dehydroepiandrosterone was the main constituent of the androgen excess. Otherwise the adrenocortical function was found to be normal as evaluated from measurements of cortisol, corticosterone and their metabolites under basal conditions and during dynamic tests. The androgen excess showed an unexpected response to trophic hormones. Human chorionic gonadotrophin stimulation resulted in a pronounced increase in androgen production, whereas no gonadotrophin-dependency could be demonstrated by means of the oestrogen suppression test. Similarly, no corticotrophin-dependency could be demonstrated by corticotrophin stimulation and suppression tests. Removal of the tumour resulted in normalization of the androgen production and no abnormal response upon human chorionic gonadotrophin administration could now be found. The inappropriate response of tumours to trophic hormones is discussed. It is concluded that the reliability of stimulation and suppression tests in determining the site of excessive androgen production should be accepted with reservation.

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PLASMA CONCENTRATION OF TESTOSTERONE IN YOUNG BULLS IN RELATION TO AGE, RATE OF WEIGHT GAIN AND STIMULATION WITH HUMAN CHORIONIC GONADOTROPHIN

Journal of Endocrinology ◽

10.1677/joe.0.0860465 ◽

1980 ◽

Vol 86 (3) ◽

pp. 465-469 ◽

Cited By ~ 11

Author(s):

ANNE SUNDBY ◽

WEIERT VELLE

Keyword(s):

Weight Gain ◽

Correlation Coefficients ◽

Multiple Correlation Coefficient ◽

Chorionic Gonadotrophin ◽

Human Chorionic Gonadotrophin ◽

Daily Weight Gain ◽

Plasma Testosterone ◽

Testosterone Concentration ◽

Subsequent Decrease ◽

The Difference

In 86 bulls ranging in age between 3 and 11 months, the maximal plasma testosterone concentration (n = 7) well as the mean concentration (n = 7, same samples) were found to increase with age to peak values at 7–8 months with a subsequent decrease. The multiple correlation coefficient for monthly gain as a function of testosterone concentration and age was 0·85 (P <0·001), for monthly gain as a function of age 0·84 (P <0·001) and for monthly gain as a function of testosteroneconcentration 0·44 (P <0·001). The deviation in levels of measured plasma testosterone from the curve expressed by multiple regression analyses of testosterone concentration as a function of age was correlated with the average daily weight gain during the testing period of 9 months and found to be not significant (r = 0·21). The difference between concentrations of plasma testosterone after stimulation with human chorionic gonadotrophin (HCG) and the spontaneous maximal concentration of this hormone was not significant. High correlation coefficients were found between maximal (r = 0·8) and mean (r = 0·6) concentrations of plasma testosterone before and after an injection of HCG (P <0·001).

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Effect of a single injection of human chorionic gonadotrophin on testosterone levels in testicular interstitial fluid, and in testicular and peripheral venous blood in adult rats

Journal of Endocrinology ◽

10.1677/joe.0.1210311 ◽

1989 ◽

Vol 121 (2) ◽

pp. 311-316 ◽

Cited By ~ 7

Author(s):

S. Maddocks ◽

B. P. Setchell

Keyword(s):

Interstitial Fluid ◽

Single Injection ◽

Venous Blood ◽

Chorionic Gonadotrophin ◽

Human Chorionic Gonadotrophin ◽

Blood Levels ◽

Adult Rats ◽

Peripheral Venous Blood ◽

Testosterone Levels ◽

Anaesthetized Rats

ABSTRACT We have used a push–pull cannula to collect interstitial fluid from the testes of anaesthetized rats at various times after a single injection of human chorionic gonadotrophin (hCG; 50 IU), and compared the levels of testosterone in this fluid with the levels in testicular and peripheral venous blood collected at the same times. Following hCG injection, significant increases in testosterone concentrations were observed in all fluids with notable peaks occurring in interstitial fluid at 2, 8 and 24 h, in testicular venous blood at 2, 8 and 30 h, and in peripheral venous blood at 2, 8, 24 and 72 h. The results demonstrate for the first time that changes in testosterone concentrations in interstitial fluid can be different from those in testicular venous blood. In addition, when testosterone levels in interstitial fluid were compared with levels in testicular venous blood at each time-point, the results suggested that the partitioning of testosterone between these two compartments can be regulated. Furthermore, the changes in both interstitial fluid and testicular venous blood levels of testosterone do not always parallel those in peripheral venous blood, suggesting that changes in testicular blood flow and peripheral clearance rates of testosterone may also be important in the control of circulating testosterone concentrations. Journal of Endocrinology (1989) 121, 311–316

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