THE EFFECT OF LOCAL TESTICULAR IRRADIATION ON TESTICULAR HISTOLOGY AND PLASMA HORMONE LEVELS IN THE MALE RAT

1978 ◽  
Vol 87 (2) ◽  
pp. 413-423 ◽  
Author(s):  
C. R. N. Hopkinson ◽  
B. Dulisch ◽  
G. Gauss ◽  
W. Hilscher ◽  
C. Hirschhäuser
Keyword(s):  
Adult Male ◽  
Sertoli Cells ◽  
Male Rats ◽  
Male Rat ◽  
Hormone Levels ◽  
Testosterone Levels ◽  
Plasma Hormone ◽  
Testicular Histology

ABSTRACT Adult male rats were subjected to local testicular irradiation, plasma hormone levels and testicular histology being quantified at intervals up to 52 days thereafter. LH and FSH increased coincidently with spermatid but not with spermatocyte or spermatogonia depletion. Testosterone levels seemed to decrease but this effect was not significant. Oestradiol levels showed no significant changes. From the correlations between the various parameters it was concluded that the lack of inhibin was the main cause of the increase in both LH and FSH and that spermatids provide the signal for production of this non-steroidal inhibitor. The site of inhibin production was not definitively established but the results would be consistent with production of inhibin by the Sertoli cells in association with spermatids.

THE EFFECT OF ARTIFICIAL CRYPTORCHIDISM ON SERUM OESTROGEN AND TESTOSTERONE LEVELS IN THE ADULT MALE RAT

1975 ◽  
Vol 80 (3) ◽  
pp. 583-591 ◽  
Author(s):  
R. W. Hall ◽  
W. R. Gomes
Keyword(s):  
Adult Male ◽  
Male Rats ◽  
Male Rat ◽  
Testosterone Levels ◽  
Minor Contribution ◽  
Adult Male Rat ◽  
And Control

ABSTRACT Oestrone, oestradiol and testosterone levels were measured by radioimmunoassay in male rats 0.5, 1, 4, 8 and 16 days after rats were either made artificially cryptorchid or sham-operated. Oestradiol levels were not significantly different between cryptorchid and control rats 12 h or 1 day after surgery, but levels in cryptorchid animals fell to 35 % of controls on day 4 (P < 0.05), 31% on day 8, and 29% on day 16 (P < 0.01). Conversely, oestrone and the total of the two oestrogens was higher in cryptorchid rats at one-half day (P <0.05), but did not differ at any other time. Testosterone levels were generally lower in cryptorchid rats than in controls. The minor contribution of oestradiol to total oestrogen levels and the lack of change of total oestrogens in cryptorchid rats led to the conclusion that oestrogens are probably not the tubular regulator of FSH in the male.

HYPOTHALAMIC-PITUITARY-TESTICULAR SYSTEM AND ADRENOCORTICAL FUNCTION

1976 ◽  
Vol 81 (1) ◽  
pp. 198-207 ◽  
Author(s):  
H. L. Verjans ◽  
K. B. Eik-Nes
Keyword(s):  
Adrenal Gland ◽  
Blood Serum ◽  
Adult Male ◽  
Serum Levels ◽  
Male Rats ◽  
Intramuscular Administration ◽  
Adrenocortical Function ◽  
Male Rat ◽  
Pituitary Secretion ◽  
Slight Elevation

ABSTRACT Effect of intramuscular administration of ACTH or dexamethasone on blood serum levels of testosterone, LH and FSH was examined in intact and castrated, adult, male rats. Six IU ACTH or 1 mg dexamethasone were given daily for 7 days. Corticotrophin treatment had no influence on circulating testosterone, LH and FSH in intact or castrated male rats. Dexamethasone administration resulted in a slight elevation of serum FSH in intact animals but not in castrates. LH and testosterone remained normal in both intact and castrated animals injected with dexamethasone. Under our conditions of study the secretions from the adrenal gland appear to be insignificant for the regulation of pituitary secretion of gonadotrophins in the male rat.

SHORT-TERM EFFECTS OF COPULATION, HUMAN CHORIONIC GONADOTROPHIN INJECTION AND NON-TACTILE ASSOCIATION WITH A FEMALE ON TESTOSTERONE LEVELS IN THE MALE RAT

1974 ◽  
Vol 60 (3) ◽  
pp. 429-439 ◽  
Author(s):  
K. PURVIS ◽  
N. B. HAYNES
Keyword(s):  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Physical Contact ◽  
Male Rats ◽  
Male Rat ◽  
Plasma Testosterone ◽  
Short Term ◽  
Testosterone Levels ◽  
Peripheral Plasma ◽  
First Contact

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.

Fluctuations in Plasma Testosterone Levels in Adult Male Rats and Mice

Endocrinology ◽  
1973 ◽  
Vol 92 (4) ◽  
pp. 1223-1228 ◽  
Author(s):  
A. BARTKE ◽  
R.E. STEELE ◽  
N. MUSTO ◽  
B.V. CALDWELL
Keyword(s):  
Adult Male ◽  
Male Rats ◽  
Plasma Testosterone ◽  
Testosterone Levels ◽  
Rats And Mice

scholarly journals Constant lighting conditions affect sexual behaviour and hormone levels in adult male rats

Reproduction ◽  
1984 ◽  
Vol 72 (2) ◽  
pp. 435-441 ◽  
Author(s):  
B. D. Fantie ◽  
R. E. Brown ◽  
W. H. Moger
Keyword(s):  
Adult Male ◽  
Sexual Behaviour ◽  
Male Rats ◽  
Hormone Levels ◽  
Lighting Conditions

scholarly journals In vitro pituitary and testicular effects of the leptin-related synthetic peptide leptin(116-130) amide involve actions both similar to and distinct from those of the native leptin molecule in the adult rat

2000 ◽  
pp. 406-410 ◽  
Author(s):  
M Tena-Sempere ◽  
L Pinilla ◽  
LC Gonzalez ◽  
J Navarro ◽  
C Dieguez ◽  
...  
Keyword(s):  
Body Weight ◽  
Adult Male ◽  
Body Weight Gain ◽  
Biologically Active ◽  
Male Rats ◽  
Male Rat ◽  
Gh Secretion ◽  
Adult Rat ◽  
Testosterone Secretion

The obese gene (ob) product, leptin, has recently emerged as a key element in body weight homeostasis, neuroendocrine function and fertility. Identification of biologically active, readily synthesized fragments of the leptin molecule has drawn considerable attention, as they may provide a powerful tool for detailed characterization of the biological actions of leptin in different experimental settings. Recently, a fragment of mouse leptin protein comprising amino acids 116-130, termed leptin(116-130) amide, was shown to mimic the effects of the native molecule in terms of body weight gain and food intake, and to elicit LH and prolactin (PRL) secretion in vivo. As a continuation of our previous experimental work, the present study reports on the effects of leptin(116-130) amide on basal and stimulated testosterone secretion by adult rat testis in vitro. In addition, a comparison of the effects of human recombinant leptin and leptin(116-130) amide at the pituitary level on the patterns of LH, FSH, PRL and GH secretion is presented. As reported previously by our group, human recombinant leptin(10(-9)-10(-7)M) significantly inhibited both basal and human chorionic gonadotrophin (hCG)-stimulated testosterone secretion in vitro. Similarly, incubation of testicular tissue in the presence of increasing concentrations of leptin(116-130) amide (10(-9)-10(-5)M) resulted in a dose-dependent inhibition of basal and hCG-stimulated testosterone secretion; a reduction that was significant from a dose of 10(-7)M upwards. In addition, leptin(116-130) amide, at all doses tested (10(-9)-10(-5)M), significantly decreased LH and FSH secretion by incubated hemi-pituitaries from adult male rats. In contrast, in the same experimental protocol, recombinant leptin(10(-9)-10(-7)M) was ineffective in modulating LH and FSH release. Finally, neither recombinant leptin nor leptin(116-130) amide were able to change basal PRL and GH secretion in vitro. Our results confirm the ability of leptin, acting at the testicular level, to inhibit testosterone secretion, and map the effect to a domain of the leptin molecule that lies between amino acid residues 116 and 130. In addition, we provide evidence for a direct inhibitory action of leptin(116-130) amide on pituitary LH and FSH secretion, a phenomenon not observed for the native leptin molecule, in the adult male rat.

EFFECTS OF FOLLICLE-STIMULATING HORMONE AND LUTEINIZING HORMONE ON PLASMA TESTOSTERONE LEVELS IN HYPOPHYSECTOMIZED AND IN INTACT IMMATURE AND ADULT MALE RATS

1974 ◽  
Vol 61 (2) ◽  
pp. 193-198 ◽  
Author(s):  
S. EL SAFOURY ◽  
A. BARTKE
Keyword(s):  
Luteinizing Hormone ◽  
Adult Male ◽  
Follicle Stimulating Hormone ◽  
Seminal Vesicles ◽  
Male Rats ◽  
Plasma Testosterone ◽  
Adult Rats ◽  
Testosterone Levels ◽  
Hypophysectomized Rats ◽  
Stimulating Hormone

SUMMARY The effects of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) on plasma testosterone levels were examined in hypophysectomized and in intact immature and adult male rats. The animals were injected with saline, LH, FSH, or both gonadotrophins twice daily for 3·5 days and were killed 3 h after the last injection. Plasma testosterone levels were measured by radioimmunoassay. In immature hypophysectomized rats, plasma testosterone levels were not changed by treatment with LH, FSH or LH plus FSH. The weight of the testes and of the seminal vesicles was increased only in animals injected with both LH and FSH. In adult hypophysectomized rats, LH caused the expected increase in plasma testosterone levels, while FSH injected alone had no effect. Plasma testosterone levels in rats treated with 5 μg LH and 20 μg FSH were significantly greater than those in animals given 5 μg LH alone. However, the same dose of FSH did not potentiate the action of 25 μg LH on plasma testosterone levels. In adult hypophysectomized rats the weight of testes was not affected by any of the treatments. The weight of the seminal vesicles was increased by the higher dose of LH and addition of FSH caused no further increase. In intact immature and adult rats plasma testosterone levels and the weight of testes were not changed by any of the treatments. Seminal vesicle weight was increased only in adult rats treated with the higher dose of LH together with FSH. The results demonstrate that FSH potentiates the action of low doses of LH on plasma testosterone levels in adult hypophysectomized rats and suggest that FSH may be involved in the regulation of androgen secretion by the rat testis.

Effects of Serotonin on Reproductive Hormone Levels and Testis Morphology in Adult Male Rats

1982 ◽  
Vol 170 (4) ◽  
pp. 464-470 ◽  
Author(s):  
M. A. Niaraki ◽  
M. G. Subramanian ◽  
K. S. Moghissi
Keyword(s):  
Adult Male ◽  
Male Rats ◽  
Reproductive Hormone ◽  
Hormone Levels
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