Mechanism delineating differential effect of an antiestrogen, tamoxifen, on the serum LH and FSH in adult male rats

2006 ◽  
Vol 29 (6) ◽  
pp. 485-496 ◽  
Author(s):  
N. Balasinor ◽  
P. Parte ◽  
M. K. Gill-Sharma ◽  
J. Kini ◽  
H. S. Juneja
Keyword(s):  
Adult Male ◽  
Differential Effect ◽  
Male Rats ◽  
Serum Lh

GONADOTROPHIN SUPPRESSION BY STEROIDS IN NORMAL, ADULT MALE RATS

1977 ◽  
Vol 84 (4) ◽  
pp. 842-849 ◽  
Author(s):  
H. L. Verjans ◽  
K. B. Eik-Nes
Keyword(s):  
Body Weight ◽  
High Activity ◽  
Adult Male ◽  
Subcutaneous Administration ◽  
Serum Levels ◽  
Steroid Treatment ◽  
Male Rats ◽  
Normal Adult ◽  
Serum Lh ◽  
Testosterone Metabolites

ABSTRACT Effects of subcutaneous administration of various doses of different steroids on serum levels of LH and FSH in normal, adult male rats were investigated. Each steroid was injected daily during 7 days in doses of 50, 25, 12.5 or 6.25 μg per 100 g body weight. Ring A 5α-reduced testosterone metabolites exerted high activity in suppressing serum LH and FSH levels. 5α-Androstane-3β,17β-diol had in the doses tested, however, no such effects on serum gonadotrophins. Serum LH concentrations in normal rats appeared more sensitive to steroid treatment than serum FSH concentrations.

The contribution of corticosterone and testosterone to the suppression of serum LH in hyperprolactinaemic adult male rats with pituitary transplants

1987 ◽  
Vol 113 (1) ◽  
pp. 111-116 ◽  
Author(s):  
R. F. A. Weber ◽  
M. P. Ooms ◽  
J. T. M. Vreeburg
Keyword(s):  
Adult Male ◽  
Serum Testosterone ◽  
Serum Levels ◽  
Male Rats ◽  
Male Rat ◽  
Serum Concentrations ◽  
Testosterone Secretion ◽  
Accessory Sex Glands ◽  
Serum Lh ◽  
Stimulation Of

ABSTRACT The effects of hyperprolactinaemia on serum levels of LH were investigated in adult male rats of the R × U strain. Hyperprolactinaemia was induced by three pituitary grafts under the kidney capsule, transplanted on day 0 of each experiment. Special attention was paid to the contribution of prolactin-stimulated testes, adrenals and corticosterone. In experiment 1, hyperprolactinaemia significantly reduced the serum concentrations of LH in intact rats. In spite of a significant increase in the serum levels of corticosterone, serum testosterone was not significantly affected by hyperprolactinaemia. The weights of both the adrenals and accessory sex glands were significantly increased at autopsy. In experiment 2, treatment with 10 mg corticosterone s.c. daily from day 14 to day 28 after pituitary grafting significantly reduced serum levels of both LH and testosterone. The suppression of testosterone in the hyperprolactinaemic corticosterone-treated animals was significantly less than in the corticosterone-treated control animals. The weights of the accessory sex glands were significantly increased in the hyperprolactinaemic animals. In experiment 3, rats were adrenalectomized and half of them were substituted with corticosterone. Serum testosterone levels significantly increased in both hyperprolactinaemic adrenalectomized rats and in adrenalectomized corticosterone-treated animals without any significant effect on serum LH. Again the weights of the accessory sex glands were significantly increased in the hyperprolactinaemic animals. In experiment 4, rats were adrenalectomized, gonadectomized and corticosterone treated on day 0 and then implanted with a 2, 1·5 or 1 cm silicone elastomer capsule containing testosterone. On day 28 after pituitary grafting, LH levels were significantly suppressed in animals with a 2 or 1·5 cm testosterone implant. The weights of the accessory sex glands were not increased in the hyperprolactinaemic animals. These results show that in the male rat the inhibitory effects of hyperprolactinaemia on serum LH levels may be due to (1) increased sensitivity of the hypothalamic-pituitary axis to the negative feedback action of testosterone by prolactin and by the prolactin-stimulated corticosterone secretion and (2) stimulation of testicular testosterone secretion by prolactin, which can also explain the increased weights of the accessory sex glands. Even in the presence of high serum concentrations of corticosterone, stimulation of testicular testosterone secretion by prolactin was observed. J. Endocr. (1987) 113,111–116

Cerebrospinal fluid and blood concentrations of luteinizing hormone, follicle stimulating hormone and prolactin following castration of adult male rats

1992 ◽  
Vol 127 (1) ◽  
pp. 58-65 ◽  
Author(s):  
Nafisa Balasinor ◽  
Manjit K Gill-Sharma ◽  
Priyanka Parte ◽  
HS Juneja
Keyword(s):  
Cerebrospinal Fluid ◽  
Adult Male ◽  
Systemic Circulation ◽  
Male Rats ◽  
Sham Operation ◽  
Turnover Rates ◽  
Blood Concentrations ◽  
Serum Lh ◽  
Norepinephrine Turnover ◽  
Hypothalamic Dopamine

Comparative levels of LH, FSH and PRL in the serum and cerebrospinal fluid (CSF) of adult male rats were studied at different periods following castration. Intact and sham-operated animals served as controls. Blood and CSF were collected at 1, 3, 7, 14, 21, 28, 35 and 46 days following castration. The CSF was collected via cisterna-magna puncture, while the blood was collected from abdominal aorta. Serum gonadotropins increased progressively beginning day 1 post-castration to reach maximum by day 35 or 46 post-castration. Sham operation and castration did not affect mean CSF, LH and FSH levels compared to intact controls. Analysis of the temporal pattern of serum and CSF gonadotropin levels following castration revealed significant positive correlation between CSF and serum LH (r=0.58) and FSH (r=0.64) levels respectively. The data suggest that CSF gonadotropins may be derived from systemic circulation. Serum PRL levels were not affected by castration, but CSF PRL levels were significantly reduced at days 28, 35 and 46 post-castration compared to intact controls. CSF PRL levels showed negative correlation with serum LH and FSH levels but failed to show a correlation with serum PRL levels. Hypothalamic norepinephrine turnover rate increased at days 28, 35 and 46 post-castration. Hypothalamic dopamine contents and turnover rates were reduced at days 21 and 28 post-castration. It is suggested that CSF PRL may have a role in the regulation of serum gonadotropins.

SEXUAL DIFFERENTIATION IN THE PHASE OF THE CIRCADIAN RHYTHM OF [35S]METHIONINE INCORPORATION INTO CEREBRAL PROTEINS, AND OF SERUM GONADOTROPHIN LEVELS

1974 ◽  
Vol 62 (2) ◽  
pp. 257-265 ◽  
Author(s):  
M. B. ter HAAR ◽  
P. C. B. MacKINNON ◽  
M. G. BULMER
Keyword(s):  
Circadian Rhythm ◽  
Circadian Rhythms ◽  
Adult Male ◽  
Anterior Pituitary ◽  
Male Rats ◽  
Normal Adult ◽  
Adult Males ◽  
Serum Luteinizing Hormone ◽  
Serum Lh ◽  
The Brain

SUMMARY The incorporation of [35S]methionine into protein in various regions of the brain and in the anterior pituitary, and serum luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels were measured at 6 h intervals throughout a 24 h period in the following groups of Wistar rats: (1) normal adult males and females; (2) adult genetic males or females which had been respectively 'feminized' or 'masculinized' by androgen deprivation or administration in neonatal life. Similar measurements were made at 12 h intervals in adult male rats which had been castrated at 7 or 15 days of age. Serum LH levels showed a circadian rhythmicity in normal adult animals of both sexes, with peak levels in the male occurring 6 h earlier than those in the female. There was no statistically significant circadian rhythm in FSH levels in any group of animals. In all groups of castrated animals LH and FSH levels were raised but no circadian rhythms were observed. Incorporation of [35S]methionine into protein in all cerebral areas showed circadian rhythms, the peak values of which, in the adult males, were almost 8 h (120°) out of phase with those of the adult females. In the 'feminized' genetic males or 'masculinized' genetic females the rhythmic phase was reversed to that of the opposite genetic sex. Animals castrated at 7 days or 15 days of age did not appear to show a rhythm. A 12 h rhythm of incorporation was apparent in the anterior pituitary of the normal adult male and the adult 'masculinized' female; no significant rhythm was seen in the normal adult female and the 'feminized' male. It is suggested that a 'female type' rhythm of incorporation in the brain may be associated with the maintenance of oestrous cycles.

Reproductive toxicity of DDT in adult male rats

2001 ◽  
Vol 20 (8) ◽  
pp. 393-397 ◽  
Author(s):  
K Ben Rhouma ◽  
O Tébourbi ◽  
R Krichah ◽  
M Sakly
Keyword(s):  
Adult Male ◽  
Pesticide Exposure ◽  
Reproductive Toxicity ◽  
Male Rats ◽  
Male Rat ◽  
Seminiferous Tubules ◽  
Serum Lh ◽  
Testicular Weight ◽  
Hypothalamic Pituitary Axis ◽  
Dose Dependent

The reproductive toxicity of DDT was investigated in adult male rats exposed to 50 and 100 mg/kg body weight (b.wt) day 1 for 10 successive days. Compared with control animals, administration of DDT led to a dose-dependent reduction of testicular weight and the number as well as the percentage of motile spermatozoa in the epididymis. Testicular histological observationsrevealed alsoamarkedloss of gametes in the lumen of seminiferous tubules. In DDT treated rats, the seminal vesicles weights dropped significantly, resulting from a decrease of testosterone production by testes, whereas serum LH and FSH increased after pesticide exposure. This increase of gonadotrophin levels may be related to an impairment of the negative feedback exerted by the steroid on the hypothalamic–pituitary axis. It is concluded that DDT induced adverse effects on male rat fertility by acting directly on the testes and altering the neuroendocrinefunction.

SERUM LH AND FSH LEVELS FOLLOWING INTRAVENOUS INJECTION OF A GONADOTROPHIN RELEASING PRINCIPLE IN NORMAL AND GONADECTOMIZED ADULT MALE RATS TREATED WITH OESTRADIOL-17β OR 5α-DIHYDROTESTOSTERONE

1976 ◽  
Vol 83 (3) ◽  
pp. 493-505 ◽  
Author(s):  
H. L. Verjans ◽  
K. B. Eik-Nes
Keyword(s):  
Intravenous Injection ◽  
Adult Male ◽  
Response Pattern ◽  
Sesame Oil ◽  
Male Rats ◽  
Intact Control ◽  
Serum Lh ◽  
Hypothalamic Pituitary Axis ◽  
Pre Treatment ◽  
Higher Doses

ABSTRACT Effect of intravenous administration of a synthetic gonadotrophin releasing factor (GnRF) on circulating LH and FSH concentrations was investigated in normal and gonadectomized, adult male rats injected subcutaneously each day during seven days with various doses of oestradiol-17β or 5α-dihydrotestosterone in sesame oil. Higher increase in serum LH and FSH levels subsequent to intravenously administered GnRF was observed in castrated control animals than in intact control animals, though this increment was not of significant nature for serum FSH. Pre-treatment of normal and gonadectomized rats with oestradiol-17β resulted in an augmented response of serum LH and FSH concentrations to GnRF iv. Pre-treatment of normal and gonadectomized rats with 5α-dihydrotestosterone diminished serum LH and FSH response following administration of the same amount of GnRF. For these steroids to affect the response pattern of serum LH and FSH to GnRF iv, higher doses were required in normal than in gonadectomized animals. The data indicate that oestrogen and androgen may act at different sites in the male hypothalamic-pituitary axis with respect to regulation of pituitary gonadotrophins.

TESTOSTERONE AND OESTRADIOL SUPPRESSION OF LH AND FSH IN ADULT MALE RATS: DURATION OF CASTRATION, DURATION OF TREATMENT AND COMBINED TREATMENT

1973 ◽  
Vol 73 (1) ◽  
pp. 11-21 ◽  
Author(s):  
R. S. Swerdloff ◽  
P. C. Walsh
Keyword(s):  
Adult Male ◽  
Testosterone Propionate ◽  
Combined Treatment ◽  
Male Rats ◽  
Low Doses ◽  
Duration Of Treatment ◽  
Serum Lh ◽  
Oestradiol Benzoate ◽  
Hypothalamic Pituitary Axis ◽  
Androgen Effect

ABSTRACT The effects of androgens and oestrogens on serum LH and FSH in castrated rats were evaluated with regard to the modifying influences of duration of castration, duration of treatment and combined oestrogen-androgen effect. Serum LH was not greatly influenced by these variables. In contrast, serum FSH was shown to be more resistant to suppression by both steroids after at least five days of castration, requiring a longer duration of treatment to be suppressed to intact levels. Combined treatment of submaximally suppressive doses of testosterone propionate and oestradiol benzoate resulted in no additive effect on lowering serum FSH. Low doses of both androgens and oestrogens resulted in elevated levels of serum LH and FSH, suggesting that the adult male hypothalamic-pituitary axis may be responsive to positive feedback. In all studies, testosterone preferentially suppressed serum LH as compared to serum FSH. In contrast, oestradiol administration produced parallel inhibition of both LH and FSH. It is emphasized that neither oestrogen nor androgen alone, nor in combination, resulted in preferential inhibition of serum FSH over LH.

Effects of an organophosphate pesticide, quinalphos, on the hypothalamo-pituitary-gonadal axis in adult male rats

Reproduction ◽  
2000 ◽  
pp. 29-38 ◽  
Author(s):  
R Sarkar ◽  
KP Mohanakumar ◽  
M Chowdhury
Keyword(s):  
Biogenic Amines ◽  
Adult Male ◽  
Chronic Administration ◽  
Pituitary Hormones ◽  
Male Rats ◽  
Pesticide Treatment ◽  
Serum Lh ◽  
Testicular Morphology ◽  
Chemiluminescent Immunoassay ◽  
Lethal Doses

The effects of chronic sub-lethal doses (7-14 mg kg-1 a day for 15 days) of quinalphos were evaluated in adult male rats for changes in testicular morphology, circulatory concentrations of hormones (LH, FSH, prolactin and testosterone), activities of acetylcholinesterase (AChE) and angiotensin converting enzyme (ACE) as well as metabolism of biogenic amines (dopamine, noradrenaline and 5-hydroxytryptamine (5-HT)) in the hypothalamus and pituitary. Hormones were assayed by radioimmunoassay or chemiluminescent immunoassay (testosterone). The enzymes were estimated after spectrophotometry and the biogenic amines by HPLC-electrochemistry. Sub-lethal chronic administration of quinalphos resulted in: decreased testicular mass and AChE activity in central as well as peripheral organs; increased serum LH, FSH, prolactin and testosterone concentrations; decreased pituitary or increased testicular ACE activity; severe disruption of spermatogenesis with increasing doses of pesticide; and no significant effects on dopamine, noradrenaline or 5-HT concentrations in the hypothalamus or pituitary. Administration of oestradiol (50 micrograms per rat a day) during pesticide treatment resulted in: a significant decrease in the mass of the testis and accessory sex organs; decreases in serum LH, FSH, testosterone concentrations; an increase in prolactin concentration; and a decrease in dopamine or an increase in noradrenaline and 5-HT in the hypothalamus or pituitary. Oestradiol had a marked effect: in pesticide-treated animals, the pesticide effects were significantly reversed. This indicates that in pesticide toxicity, the hypothalamo-pituitary-gonadal axis is operational. Since many of the observed pesticide effects could be inhibited by oestradiol, it is suggested that the pesticide acts directly on the gonadotrophins. In conclusion, quinalphos decreases fertility in adult male rats by affecting the pituitary gonadotrophins.

SHORT-TERM EFFECTS OF CASTRATION AND STARVATION UPON PITUITARY AND SERUM LEVELS OF LUTEINIZING HORMONE AND FOLLICLE STIMULATING HORMONE IN MALE RATS

1972 ◽  
Vol 70 (4) ◽  
pp. 665-675 ◽  
Author(s):  
Allen W. Root ◽  
R. David Russ
Keyword(s):  
Luteinizing Hormone ◽  
Adult Male ◽  
Follicle Stimulating Hormone ◽  
Serum Levels ◽  
Male Rats ◽  
Serum Concentrations ◽  
Short Term ◽  
Serum Lh ◽  
Total Starvation ◽  
Stimulating Hormone

ABSTRACT Serum and pituitary levels of luteinizing hormone (LH) and follicle stimulating hormone (FSH) were measured by radioimmunoassay in intact and castrated juvenile (21 days) and adult male rats. The effect of total starvation upon the gonadotrophin response to castration was also investigated in adult animals. In rats castrated at 21 days of age, serum and pituitary levels of LH were elevated by 7 days and increased progressively for 4 weeks. Serum concentrations of FSH also increased within 7 days and remained stable thereafter. Pituitary FSH levels initially declined and then increased. In adult animals serum LH and FSH concentrations increased after castration. Pituitary LH values also increased, while FSH levels remained stable for 14 days after operation. Serum FSH concentrations were consistently decreased in starved-intact animals. Starvation partially inhibited castration-induced release of LH without affecting pituitary LH or FSH synthesis or FSH release.

EFFECTS OF TESTOSTERONE PROPIONATE, 5α-DIHYDROTESTOSTERONE PROPIONATE AND OESTRADIOL BENZOATE ON SERUM LEVELS OF LH AND FSH IN THE CASTRATED ADULT MALE RAT

1974 ◽  
Vol 77 (4) ◽  
pp. 643-654 ◽  
Author(s):  
H. L. Verjans ◽  
K. B. Eik-Nes ◽  
J. H. Aafjes ◽  
F. J. M. Vels ◽  
H. J. van der Molen
Keyword(s):  
Adult Male ◽  
Testosterone Propionate ◽  
Serum Levels ◽  
Seminal Vesicles ◽  
Male Rats ◽  
Male Rat ◽  
Low Doses ◽  
Serum Lh ◽  
Oestradiol Benzoate ◽  
Adult Male Rat

ABSTRACT The influence of treatment with various doses of testosterone propionate, 5α-dihydrotestosterone propionate or oestradiol benzoate on serum levels of LH and FSH (measured by radioimmunoassay) and on weights of ventral prostates and seminal vesicles was investigated in castrated, adult, male rats. For depression of the high, castrate levels of serum gonadotrophins with either of these steroid esters, the inhibition curves were different for LH and for FSH. Serum LH was kept at levels encountered in intact, adult, male rats by lower doses of steroid ester than was serum FSH. Oestradiol benzoate was the most potent suppressor of the serum gonadotrophins among the steroid esters tested, testosterone propionate the least. Treatment with low doses of oestradiol benzoate, however, resulted in serum FSH levels significantly above those of castrates treated with vehicle only. Finally, administration of a synthetic LH-releasing factor to testosterone propionate, 5α-dihydrotestosterone propionate or oestradiol benzoate treated, castrated, adult, male rats resulted in a further release of both LH and FSH. The latter effect was more pronounced in oestradiol benzoate treated castrates than in testosterone propionate or 5α-dihydrotestosterone propionate treated castrates.

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