Influence of pinealectomy on the suppression of gonadotrophin secretion induced by hyperprolactinaemia in the adult male rat

To investigate the role of the pineal gland in the long-term suppression of gonadotrophin secretion induced by prolactin, the effects of pinealectomy were studied in adult male rats with hyperprolactinaemia produced by the transplantation of two pituitary glands under the kidney capsule. Pinealectomy had no effect on basal levels of LH, FSH or prolactin. The presence of pituitary transplants induced a significant twofold increase in prolactin levels and a prolonged suppression in both LH and FSH. These changes were not affected by pinealectomy. Castration resulted in a similar rise in plasma levels of LH and FSH in rats with and without pituitary transplants. In control rats this rise in LH and FSH was reduced by testosterone-containing silicone elastomer implants (s.c) of 10 mm in length and delayed by implants of 30 mm. These rises in LH and FSH were significantly delayed (10-mm implant) or abolished (30-mm implant) in rats with pituitary transplants indicating an increase in sensitivity of the hypothalamic-pituitary axis to the negative feedback effects of testosterone in these animals compared to controls. These responses were not affected by pinealectomy. These results suggest that the pineal gland is not involved in the mechanism whereby pituitary grafts, possibly through their secretion of prolactin, cause long-term suppression of gonadotrophin secretion.

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

Journal of Endocrinology ◽

10.1677/joe.0.0850083 ◽

1980 ◽

Vol 85 (1) ◽

pp. 83-92 ◽

Cited By ~ 8

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.

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Diurnal Variations of Plasma Growth Hormone and Brain Monoamines in Adult Male Rats

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y73-137 ◽

1973 ◽

Vol 51 (12) ◽

pp. 890-892 ◽

Cited By ~ 17

Author(s):

R. Collu ◽

J. C. Jéquier ◽

J. Letarte ◽

G. Leboeuf ◽

J. R. Ducharme

Keyword(s):

Growth Hormone ◽

Adult Male ◽

Physiological Role ◽

Male Rats ◽

Male Rat ◽

Plasma Growth Hormone ◽

Gh Secretion ◽

Adult Male Rat ◽

Plasma Gh

Brain levels of monoamines (MA) in the adult male rat show a diurnal pattern of secretion with noradrenaline (NA) and serotonin (5-HT) reaching a peak at 1300 and 1800, respectively, and dopamine (DA) showing a bimodal pattern with peaks at 0500 and 1800. Plasma growth hormone (GH) values fluctuate widely during the nycthemeral period. Statistically significant correlations between plasma GH and brain MA levels, confirming the existence of a physiological role of MA in the control of GH secretion, could not be demonstrated in the present study.

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Tramadol Promotes Oxidative Stress, Fibrosis, Apoptosis, Ultrastructural and Biochemical alterations in the Adrenal Cortex of Adult Male Rat with Possible Reversibility after Withdrawal

Microscopy and Microanalysis ◽

10.1017/s1431927620001397 ◽

2020 ◽

Vol 26 (3) ◽

pp. 509-523 ◽

Cited By ~ 1

Author(s):

Amany Mohamed Shalaby ◽

Adel Mohamed Aboregela ◽

Mohamed Ali Alabiad ◽

Dina Fouad El Shaer

Keyword(s):

Adrenal Cortex ◽

Adult Male ◽

Smooth Endoplasmic Reticulum ◽

Dehydroepiandrosterone Sulfate ◽

Male Rats ◽

Male Rat ◽

Control Group ◽

Biochemical Alterations ◽

Adult Male Rat

AbstractTramadol is a centrally acting analgesic drug, used for the management of moderate to severe pain in a variety of diseases. The long-term use of tramadol can induce endocrinopathy. This study aimed to evaluate the effect of tramadol dependence on the adrenal cortex and the effect of its withdrawal. Thirty adult male rats were divided into three experimental groups: the control group, the tramadol-dependent group that received increasing therapeutic doses of tramadol orally for 1 month, and the recovery group that received tramadol in a dose and duration similar to the previous group followed by a withdrawal period for another month. Specimens from the adrenal cortex were processed for histological, immunohistochemical, enzyme assay, and quantitative real-time PCR (RT-qPCR) studies. Tramadol induced a significant increase in malondialdehyde level and a significant decrease in the levels of glutathione peroxidase and superoxide dismutase. A significant decrease in the levels of adrenocorticotrophic hormones, aldosterone, cortisol, corticosterone, and dehydroepiandrosterone sulfate was also detected. Severe histopathological changes in the adrenal cortex were demonstrated in the form of disturbed architecture, swollen cells, and shrunken cells with pyknotic nuclei. Inflammatory cellular infiltration and variable-sized homogenized areas were also detected. A significant increase in P53 and Bax immunoreaction was detected and confirmed by RT-qPCR. The ultrastructural examination showed irregular, shrunken adrenocorticocytes with dense nuclei. Dilated smooth endoplasmic reticulum, mitochondria with disrupted cristae, and numerous coalesced lipid droplets were also demonstrated. All these changes started to return to normal after the withdrawal of tramadol. Thus, it was confirmed that the long-term use of tramadol can induce severe adrenal changes with subsequent insufficiency.

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