CONCENTRATIONS OF TESTOSTERONE IN NEONATAL MALE RATS SUCKLED NATURALLY AND HAND-FED

1982 ◽  
Vol 92 (3) ◽  
pp. 419-424 ◽  
Author(s):  
P. J. B. ANDERSON ◽  
A. E. FATINIKUN ◽  
A. D. SWIFT
Keyword(s):  
Human Milk ◽  
Plasma Levels ◽  
Male Rats ◽  
Male Rat ◽  
Plasma Testosterone ◽  
Milk Replacer ◽  
Testosterone Concentration ◽  
Rat Pups ◽  
Lh Rh ◽  
Lh Releasing Hormone

Concentrations of testosterone were measured daily in plasma of neonatal male rats from the day of birth for 7 days. It was found that a significant (P <0·001) increase in mean plasma levels of testosterone occurs on day 2 of life, followed by a decrease on day 3. Separation of male rat pups from their mothers on the second day of life for as little as 2 h was associated with a significant (P <0·001) fall in plasma testosterone concentration. Hand-feeding the pups with a proprietary human milk substitute (milk-replacer) from birth until the expected time of the testosterone peak resulted in no increase in plasma levels of testosterone; inclusion of an antiserum to LH-releasing hormone (LH-RH) in the milk-replacer decreased the testosterone levels as did removing any supposed endogenous LH-RH in the milk replacer. Addition of a highly potent analogue of LH-RH, either in the presence or absence of the LH-RH antiserum, to the milk-replacer resulted in mean plasma levels of testosterone similar to those in naturally suckled rats. Rats fed with human milk showed an increase in plasma levels of testosterone. It is concluded that the increase in the plasma testosterone concentration found in male rat pups on the second day of life, which may have an important effect on the organization of the brain, is provoked indirectly by LH-RH ingested during suckling.

scholarly journals Maternal Perinatal Undernutrition Drastically Reduces Postnatal Leptin Surge and Affects the Development of Arcuate Nucleus Proopiomelanocortin Neurons in Neonatal Male Rat Pups

Endocrinology ◽  
2007 ◽  
Vol 149 (2) ◽  
pp. 470-475 ◽  
Author(s):  
Fabien Delahaye ◽  
Christophe Breton ◽  
Pierre-Yves Risold ◽  
Mihaela Enache ◽  
Isabelle Dutriez-Casteloot ◽  
...  
Keyword(s):  
Gene Expression ◽  
Plasma Levels ◽  
Metabolic Disorders ◽  
Arcuate Nucleus ◽  
Nerve Fibers ◽  
Male Rats ◽  
Male Rat ◽  
Maternal Undernutrition ◽  
Rat Pups ◽  
Plasma Leptin

A growing body of evidence suggests that maternal undernutrition sensitizes the offspring to the development of energy balance metabolic disorders such as type 2 diabetes, dyslipidemia, and obesity. The present study aimed at examining the impact of maternal undernutrition on leptin plasma levels in newborn male rats and on the arcuate nucleus proopiomelanocortin (POMC) and neuropeptide Y (NPY) neurons that are major leptin targets. Using a model of perinatal maternal 50% food-restricted diet (FR50) in the rat, we evaluated leptin plasma levels and hypothalamic POMC and NPY gene expression from postnatal day (PND) 4 to PND30 in both control and FR50 offspring. In control rats, a postnatal peak of plasma leptin was observed between PND4 and PND14 that reached a maximal value at PND10 (5.17 ± 0.53 ng/ml), whereas it was dramatically reduced in FR50 pups with the higher concentration at PND7 (0.93 ± 0.23 ng/ml). In FR50 animals, using semiquantitative RT-PCR and in situ hybridization, we showed that the hypothalamic POMC mRNA level was decreased from PND14 until PND30, whereas NPY gene expression was not significantly modified. In PND21 FR50 animals, we observed strikingly reduced immunoreactive β-endorphin nerve fibers projecting to the hypothalamic paraventricular nucleus without affecting NPY projections. Our data showed that maternal undernutrition drastically reduces the postnatal surge of plasma leptin, disturbing particularly the hypothalamic wiring as well as the gene expression of the anorexigenic POMC neurons in male rat pups. These alterations might contribute to the adult metabolic disorders resulting from perinatal growth retardation.

EFFECT OF ADRENALECTOMY OR CASTRATION ON THE INHIBITION OF GONADOTROPHIN SECRETION INDUCED BY HYPERPROLACTINAEMIA IN THE ADULT MALE RAT

1980 ◽  
Vol 85 (1) ◽  
pp. 83-92 ◽  
Author(s):  
A. S. McNEILLY ◽  
R. M. SHARPE ◽  
H. M. FRASER
Keyword(s):  
Adult Male ◽  
Inhibitory Effect ◽  
Male Rats ◽  
Male Rat ◽  
Gonadotrophin Secretion ◽  
Adult Male Rat ◽  
Pituitary Glands ◽  
Lh Rh ◽  
Lh Releasing Hormone

SUMMARY To investigate the role of adrenal and gonadal steroids in the long-term suppression of gonadotrophin secretion induced by prolactin the effects of adrenalectomy or castration on the serum and pituitary levels of LH, FSH and prolactin and the hypothalamic content of LH releasing hormone (LH-RH) have been studied in adult male rats with hyper prolactinaemia produced by the transplantation of pituitary glands under the kidney capsule. Levels of LH and FSH in serum were significantly suppressed in all intact pituitary-grafted rats. Adrenalectomy on the day of pituitary implantation or 20 days later did not affect this suppression. However, castration on days 0,28 or 49 after pituitary grafting resulted in a rise in levels of FSH in serum indistinguishable from that in control rats. While the rise in levels of LH after castration on day 0 was the same as the controls, this increase was significantly reduced 2 days after castration on days 28 and 49 after pituitary grafting. Castration resulted in an increase in the pituitary content of LH and a reduction in the hypothalamic content of LH-RH but no change in the pituitary content of FSH. Hyperprolactinaemia did not appear to affect these responses. The present results showed clearly that the gonad but not the adrenal must be present for prolactin to exert an inhibitory effect on gonadotrophin secretion.

Studies on the mechanism of the selective suppression of plasma levels of follicle-stimulating hormone in the female rat after administration of steroid-free bovine follicular fluid

1983 ◽  
Vol 97 (3) ◽  
pp. 327-338 ◽  
Author(s):  
W. J. de Greef ◽  
F. H. de Jong ◽  
J. de Koning ◽  
J. Steenbergen ◽  
P. D. M. van der Vaart
Keyword(s):  
Follicular Fluid ◽  
Plasma Levels ◽  
Single Injection ◽  
Constant Infusion ◽  
Metabolic Clearance ◽  
Female Rat ◽  
Clearance Rates ◽  
Lh Rh ◽  
Lh Releasing Hormone ◽  
Hypophysial Portal

Steroid-free bovine follicular fluid (bFF) selectively suppresses the plasma levels of FSH in the female rat, demonstrating that bFF contains inhibin-like material. The present study was concerned with the effects of bFF on the hypothalamic release of LH releasing hormone (LH-RH) into hypophysial stalk blood and on the metabolic clearance rates of gonadotrophins. The metabolic clearance rates of FSH, LH and prolactin were determined after a single injection of and during a constant infusion with adenohypophysial extract. Similar results were obtained with both methods, and treatment with bFF did not alter the metabolic clearance rates of FSH, LH and prolactin. Anaesthesia with urethane, used for surgery involved in the collection of hypophysial stalk blood, did not interfere with the effect of bFF on plasma levels of FSH. The administration of bFF did not change the hypothalamic content of LH-RH, but caused a 30% decrease in the levels of LH-RH in hypophysial stalk plasma. However, a fraction isolated from bFF, which contained 20 times more inhibin-like activity per mg protein than bFF, did not alter the hypothalamic release of LH-RH into the hypophysial portal blood while this fraction was effective in specifically suppressing the plasma levels of FSH. It was concluded that the inhibin-like activity in bFF does not suppress the plasma levels of FSH by affecting its plasma clearance or by influencing the hypothalamic release of LH-RH, but that it has a direct effect on the adenohypophysis in inhibiting the release of FSH. Besides the inhibin-like activity, bFF also contains another factor which can decrease the levels of LH-RH in hypophysial stalk plasma.

A STUDY OF THE FIRST EIGHT HOURS IN THE STABILIZATION OF PLASMA TESTOSTERONE CONCENTRATION IN THE HEMICASTRATED RAT

1982 ◽  
Vol 92 (2) ◽  
pp. 225-229 ◽  
Author(s):  
A. I. FRANKEL ◽  
E. J. MOCK
Keyword(s):  
Low Dose ◽  
Male Rat ◽  
Plasma Testosterone ◽  
Blood Collection ◽  
Similar Response ◽  
Luteinizing Hormone Releasing Hormone ◽  
Sham Surgery ◽  
One Step ◽  
Lh Rh ◽  
Single Testis

Plasma levels of testosterone fell within 4 h after hemicastration in the mature male rat, and recovered within 8 h, without a compensatory rise in plasma LH from 5 to 480 min after surgery. Pulsatile release of LH was not observed in any group, suggesting the possibility that its alteration was not stimulating the single testis. Luteinizing hormone releasing hormone (LH-RH) stimulated plasma LH concentration equally in both control and hemicastrated rats, rising more sharply only in sham-hemicastrated rats treated with a low dose of LH-RH. Plasma LH rose significantly at the same time (6 h after surgery) in both castrated (in one step) and hemicastrated rats which were castrated (in two steps). Bilateral denervation of the testis did not affect the response of plasma testosterone after hemicastration. There was a remarkably similar response in both plasma LH and testosterone levels to handling, blood collection, anaesthesia, sham-surgery and hemicastration separately or in combination. It was concluded that the response of testosterone to hemicastration was neither related to early changes in plasma LH levels nor to alterations in the hypothalamo-hypophysial axis.

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.

scholarly journals Testosterone-dependent variations in plasma and intrapituitary corticosteroid binding globulin and stress hypothalamic-pituitary-adrenal activity in the male rat

2004 ◽  
Vol 181 (2) ◽  
pp. 223-231 ◽  
Author(s):  
V Viau ◽  
MJ Meaney
Keyword(s):  
Feedback Regulation ◽  
High Plasma ◽  
Male Rats ◽  
Testosterone Replacement ◽  
Male Rat ◽  
Plasma Testosterone ◽  
Hypothalamic Pituitary Adrenal ◽  
Corticosteroid Binding Globulin ◽  
Low Testosterone

Hypothalamic-pituitary-adrenal (HPA) activity is governed by glucocorticoid negative feedback and the magnitude of this signal is determined, in part, by variations in plasma corticosteroid-binding globulin (CBG) capacity. Here, in gonadectomized male rats we examine the extent to which different testosterone replacement levels impact on CBG and HPA function. Compared with gonadectomized rats with low testosterone replacement ( approximately 2 ng/ml), plasma adrenocorticotropin and beta-endorphin/beta-lipotropin responses to restraint stress were reduced in gonadectomized rats with high testosterone replacement ( approximately 5 ng/ml). Plasma CBG levels also varied negatively as a function of testosterone concentration. Moreover, glucocorticoid receptor binding in the liver was elevated by higher testosterone replacement, suggesting that testosterone acts to enhance glucocorticoid suppression of CBG synthesis. Since pituitary intracellular CBG (or transcortin) is derived from plasma, this prompted us to examine whether transcortin binding was similarly responsive to different testosterone replacement levels. Transcortin binding was lower in gonadectomized rats with high plasma testosterone replacement ( approximately 7 ng/ml) than in gonadectomized rats with low testosterone replacement ( approximately 2 ng/ml). This testosterone-dependent decrease in pituitary transcortin was associated, in vitro, with an enhanced nuclear uptake of corticosterone. These findings indicate that the inhibitory effects of testosterone on corticotrope responses to stress may be linked to decrements in plasma and intrapituitary CBG. This could permit greater access of corticosterone to its receptors and enhance glucocorticoid feedback regulation of ACTH release and/or proopiomelanocortin processing.

LEVELS OF LUTEINIZING HORMONE, FOLLICLE-STIMULATING HORMONE, TESTOSTERONE AND DIHYDROTESTOSTERONE IN THE CIRCULATION OF SEXUALLY MATURING INTACT MALE RATS AND AFTER ORCHIDECTOMY AND EXPERIMENTAL BILATERAL CRYPTORCHIDISM

1975 ◽  
Vol 66 (2) ◽  
pp. 183-193 ◽  
Author(s):  
D. GUPTA ◽  
K. RAGER ◽  
J. ZARZYCKI ◽  
M. EICHNER
Keyword(s):  
Plasma Levels ◽  
Follicle Stimulating Hormone ◽  
Plasma Concentrations ◽  
Gonadal Steroids ◽  
Male Rats ◽  
Plasma Testosterone ◽  
Dynamic Feedback ◽  
Gonadal Steroid ◽  
Intact Male ◽  
Bilateral Cryptorchidism

SUMMARY Plasma concentrations of LH, FSH, testosterone and dihydrotestosterone (DHT) have been measured in normal sexually maturing male rats from the age of 16–90 days. Between 16 and 25 days plasma testosterone levels were low, but rose suddenly on day 26. A similar increment occurred at the same time in plasma DHT levels, but this steroid reached its peak concentration later than testosterone. Plasma LH levels rose steadily from day 25 onwards, reaching their highest values on day 30. A marked increase in FSH levels was found on day 16, and a peak was reached on day 33 followed by a decline to a level characteristic of the adult. In addition, plasma levels of all these hormones were estimated in the male animals at various stages of development after orchidectomy and cryptorchidism. Four days after operation, the plasma levels of LH and FSH in the orchidectomized animals reached higher levels than those found in the intact animals, indicating the existence of a dynamic feedback relationship before puberty between gonadal steroids and pituitary gonadotrophic secretion. However, results from the experimental bilaterally cryptorchid animals, suggested that the gonadal steroid–gonadotrophic feedback relationship could not be the only factor initiating puberty.

scholarly journals Amelioration of testicular damages in renal ischemia/reperfusion by berberine: An experimental study

2019 ◽  
Author(s):  
Firouzeh Gholampour ◽  
Shabnam Malekpour Mansourkhani ◽  
Seyed Mohammad Owji
Keyword(s):  
Acute Kidney Injury ◽  
Plasma Levels ◽  
Ischemia Reperfusion ◽  
Kidney Injury ◽  
Renal Ischemia ◽  
Plasma Testosterone ◽  
Left Renal Artery ◽  
Functional Disorders ◽  
Urea Nitrogen ◽  
Testosterone Concentration

Background: Ischemic acute kidney injury is associated with an inflammatory reaction. Objective: In the current study, berberine was assessed for its effect on the functional disorders and histological damages of testis induced by renal ischemia/reperfusion (I/R). Materials and Methods: Twenty-eight adult male Wistar rats (260-300 gr) were equally divided into four groups (n = 7/each): sham and I/R groups which received distilled water as well as berberine (BBR) and BBR + I/R groups which received berberine (15 mg/kg/day) orally seven days before the surgery. In both groups of sham and BBR, renal arteries were not clamped. Renal I/R was induced by occluding right and left renal artery for 45 min followed by a 24 hr reperfusion period. Blood samples were taken for determining the plasma levels of creatinine, urea nitrogen, FSH (follicle stimulating hormone), LH (luteinizing hormone), and testosterone. Then the rats were killed under deep anesthesia and the left testis was immediately isolated and preserved. Results: The renal I/R injury led to testicular histological damages accompanied with increased plasma levels of creatinine, urea nitrogen, LH, and FSH, as well decrease of plasma testosterone concentration at the end of 24 hr reperfusion (All p < 0.001, except for FSH p < 0.01). Berberine diminished histological damage to the testis and attenuated the increase in plasma creatinine, urea nitrogen, LH, FSH, and decrease in plasma testosterone concentration in the BBR + I/R group (All p < 0.001). Conclusion: These results suggest that ischemic acute renal failure induces functional disorders and tissue damages in testis of rat, which was improved through the administration of berberine. Key words: Ischemia/reperfusion, Acute kidney injury, Berberine, Testis, LH, FSH.

EFFECTS OF ANTI-OESTROGEN TREATMENT OF NEONATAL MALE RATS ON LORDOSIS BEHAVIOUR AND MOUNTING BEHAVIOUR IN THE ADULT

1978 ◽  
Vol 76 (2) ◽  
pp. 241-249 ◽  
Author(s):  
P. SÖDERSTEN
Keyword(s):  
Testosterone Propionate ◽  
Neonatal Rat ◽  
Male Rats ◽  
Glans Penis ◽  
Male Rat ◽  
Plasma Testosterone ◽  
Oestrogen Treatment ◽  
Oestradiol Benzoate ◽  
Sexual Glands ◽  
Lordosis Behaviour

Male rats were treated daily with 100 μg of the anti-oestrogen ethamoxytriphetol (MER-25) or oil during the first 10 days of life and tested for lordosis behaviour and mounting behaviour as intact adults, after castration and after castration and oestradiol benzoate or testosterone propionate treatment. The MER-25-treated rats showed higher levels of lordosis behaviour than oil-treated rats in all four treatment groups. Under each of these endocrine conditions, except after castration alone, the MER-25-treated rats showed a reduced capacity to ejaculate. Treatment of the neonatal rat with MER-25 reduced body weight in adulthood but did not change the weight of the accessory sexual glands, the testes, the number of cornified papillae on the glans penis or plasma testosterone concentrations during development. The response of the accessory sexual glands and cornified papillae on the glans penis to treatment with oestradiol benzoate or testosterone propionate after castration in adulthood was unaffected by treatment with MER-25. It is suggested that formation of oestrogen in the neonatal male rat brain from testosterone in the circulation inhibits the capacity to show lordosis behaviour and facilitates the capacity to ejaculate in response to gonadal hormone treatment in adulthood.

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