Involvement of physiological prolactin levels in growth and prolactin receptor content of prostate glands and testes in developing male rats

1992 ◽  
Vol 132 (3) ◽  
pp. 449-459 ◽  
Author(s):  
B. Pérez-Villamil ◽  
E. Bordiú ◽  
M. Puente-Cueva

ABSTRACT We have investigated the role of physiological prolactin levels in the development of prepubertal male rats. Prolactin GH and testosterone levels, as well as body, ventral prostate and testicular weight, have been analysed in both control and bromocriptine-treated rats between 21 and 60 days of life. Furthermore the role of prolactin in the regulation of its own receptors has also been studied during the same period. In control rats, prolactin levels showed a prepubertal peak of secretion at 25 days of age. At this time GH and testosterone levels were low and did not show any significant variation. After this age, prolactin levels increased more gradually; determinations of GH showed great variation with low levels in most of the rats and very high values in the other animals; testosterone levels remained low until day 35 after which they increased. Simultaneously with the serum prolactin peak on day 25, a decrease in prolactin-binding capacity of ventral prostate glands, was observed and a maximum rate of body, prostate and testicular weight gain was obtained. Furthermore, in rats with pharmacologically suppressed serum prolactin levels (lower than 1 μg/l), prolactin binding to prostate glands as well as the weight of body, ventral prostate and testes were lower than in control animals. When results were expressed in mg prostate or testes/g body weight, testes from 25-day-old treated rats weighed significantly less than controls. The later stages of development, from days 25 to 60, were characterized by an initial decline in serum prolactin levels at 29 days of age which was followed by a continuous increase until adult values were reached. During this period, prostatic prolactin receptors which were at their lowest value at 33 days of age showed a gradual rise parallel with the observed increase in plasma prolactin levels. When testicular tissue was analysed, no changes in prolactin-binding sites caused by sexual maturation were observed. The present results indicate that physiological prolactin secretion has a specific effect on the normal increase in the prostate, testes and body weight and clearly is also implicated in the regulation of its prostatic receptors at the earlier stages of development. Journal of Endocrinology (1992) 132, 449–459

1995 ◽  
Vol 147 (3) ◽  
pp. 463-471 ◽  
Author(s):  
F Gaytan ◽  
C Bellido ◽  
C Morales ◽  
N van Rooijen ◽  
E Aguilar

Abstract The Leydig cells of young hypophysectomized rats are highly sensitive to the stimulatory effects of exogenous pituitary hormones. The aim of this study was to analyse the role of testicular macrophages in the response of Leydig cells to different hormones. Male rats were hypophysectomized at 28 days of age and 10 days later they were injected intratesticularly with dichloromethylene diphosphonate-containing liposomes (right testis) to deplete testicular macrophages, and with 0·9% NaCl (left testis). One week later, the animals were treated daily with 1 IU rat GH (rGH)/rat, 5 IU recombinant human FSH (recFSH)/rat, 10 IU human chorionic gonadotrophin (hCG)/rat, or vehicle for 7 days. The animals were killed on the day after the last injection. The animals treated with rGH showed increased body weight and increased number and size of testicular macrophages in the left testes, but no significant effects on Leydig cells were found. Treatment with recFSH induced a significant increase in testicular weight and tubular diameter in both testes. In the left testes, the number and size of macrophages were increased; the number of Leydig cells was not changed, although they showed a significantly increased cross-sectional area. This effect was abolished in the right (macrophage-depleted) testes. However, the effect of recFSH on the growth of the seminiferous tubules was not modified by the absence of macrophages. Rats treated with hCG showed increased testicular weight and serum testosterone levels, as well as an increased weight of the ventral prostate. In the left testes, the number and size of both macrophages and Leydig cells were increased. Otherwise, the number of Leydig cells was unchanged in the absence of macrophages, whereas the increase in the size of Leydig cells was partially abolished. These data indicate that testicular macrophages are needed for the response of Leydig cells to gonadotrophin treatment. Journal of Endocrinology (1995) 147, 463–471


Author(s):  
Gabriel O. Oludare ◽  
Gbenga O. Afolayan ◽  
Ganbotei G. Semidara

Abstract Objectives This study aimed to access the protective effects of d-ribose-l-cysteine (DRLC) on cyclophosphamide (CPA) induced gonadal toxicity in male rats. Methods Forty-eight male Sprague-Dawley rats were divided into six groups of eight rats each. Group I the control, received distilled water (10 ml/kg), Group II received a single dose of CPA 100 mg/kg body weight intraperitoneally (i.p), Groups III and IV received a single dose of CPA at 100 mg/kg (i.p) and then were treated with DRLC at 200 mg/kg bodyweight (b.w) and 400 mg/kg b.w for 10 days, respectively. Rats in Groups V and VI received DRLC at 200 and 400 mg/kg b.w for 10 days, respectively. DRLC was administered orally. Results Results showed that CPA increased percentage of abnormal sperm cells and reduced body weight, sperm count, sperm motility, follicle-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone levels (p<0.05). CPA also induced oxidative stress as indicated by the increased malondialdehyde (MDA) content and reduced activities of the oxidative enzymes measured (p<0.05). Liver enzymes were elevated while the blood cells production was decreased in the rats administered CPA. DRLC supplementation enhanced the antioxidant defence system as indicated in the reduced MDA levels and increased activities of the antioxidant enzymes when compared with CPA (p<0.05). Bodyweight, sperm count, sperm motility, FSH, and testosterone levels were increased in the CPA + DRLC II group compared with CPA (p<0.05). Conclusions The results of this present study showed that DRLC has a potential protective effect on CPA-induced gonadotoxicity.


1995 ◽  
Vol 14 (11) ◽  
pp. 889-894 ◽  
Author(s):  
N. Pant ◽  
AK Prasad ◽  
SC Srivastava ◽  
R. Shankar ◽  
SP Srivastava

1 Carbofuran was administered orally to adult male rats at dose levels of 0.1, 0.2, 0.4 or 0.8 mg kg -1 body weight, 5 d wk-1 for 60 days. A dose dependent decrease was observed in body weight of rats treated with 0.2-0.8 mg carbofuran kg -1 body weight 2 A significant decrease in the weight of epididymides, seminal vesicles, ventral prostate and coagulating glands was observed at various test doses of carbofuran except at the lowest dose. 3 Decreased sperm motility, reduced epididymal sperm count along with increased morphological abnormali ties in head, neck and tail regions of spermatozoa were observed in rats exposed to 0.2, 0.4, or 0.8 mg carbo furan kg-1 body weight. 4 In addition, significant alterations were observed in the activities of marker testicular enzymes viz. sorbitol dehydrogenase (SDH), glucose-6-P-dehydrogenase (G6PDH) (decreased), lactate dehydrogenase (LDH) and γ-glutamyl transpeptidase (γ-GT) (increased) depending on dose. 5 Histologically, the results indicated the toxicity of carbo furan on testes depending on dose. The changes pre dominantly consisted of moderate oedema, congestion, damage to Sertoli cells and germ cells, along with the accumulation of cellular debris and presence of giant cells in the lumen of a few seminiferous tubules which showed disturbed spermatogenesis with the higher doses of carbofuran. 6 These observations determined a no effect level dose of 0.1 mg kg-1 body weight of carbofuran on the biochemi cal and morphological indices studied for male repro ductive toxicity assessment in the rat model. The results of the present study provide first hand information on the reproductive toxicity of carbofuran in male rats.


Author(s):  
М. Голубева

Введение. Изменение реологических свойств крови характерно для различных заболеваний, многие из которых связаны с нарушением реологии и, прежде всего, с изменением агрегации эритроцитов. Целью исследования было сравнение влияния малых регуляторных пептидов, являющихся фрагментами нейрогормонов, на агрегацию эритроцитов и тромбоцитов под действием адреналина в экспериментах in vitro. Материалы и методы. Эксперименты проводили на белых беспородных крысах-самцах, массой тела 180-200 г. Использовали пептиды, представляющие собой С-концевые фрагменты вазопрессина (Pro-Arg-Gly-NH2) и окситоцина (Pro-Leu-Gly-NH2). Результаты. Показано, что малые регуляторные пептиды, являющиеся продуктами протеолиза нейропептидов, оказывают существенное влияние на агрегатное состояние клеток крови. При сравнении влияния пептидов на агрегацию клеток крови, стимулированную адреналином, установлено, что фрагмент вазопрессина Pro-Arg-Gly-NH2 вызывал достоверное усиление агрегации как эритроцитов, так и тромбоцитов; тогда как фрагмент окситоцина Pro-Leu-Gly-NH2 ингибировал только агрегацию эритроцитов, не изменяя агрегации тромбоцитов. Заключение. Изучение путей поэтапного протеолиза пептидов может привести к разработке новых препаратов для направленной коррекции различных нарушений в организме, поэтому изучение эффектов С-концевых фрагментов гипофизарных гормонов на гемостаз является актуальным. Introduction. The changing of blood rheological properties is typical for various diseases; many of them are associated with rheology disorder and primarily with change of erythrocytes aggregation. The aim was to compare the effect of small regulatory peptides (fragments of neurohormones) on the aggregation of erythrocytes and platelets under adrenaline action in experiments in vitro. Materials and methods. Experiments were conducted on white outbred male rats, body weight 180-200 g. We used 2 peptides – C-terminal fragments of vasopressin (Pro-Arg-Gly-NH2) and oxytocin (Pro-Leu-Gly-NH2). Results. It was shown that small regulatory peptides (they are products of neuropeptides proteolysis) had a significant effect on blood cells aggregation. We compared the peptides effect on blood cells aggregation stimulated by adrenaline. It was found that vasopressin fragment Pro-Arg-Gly-NH2 significantly increased both erythrocytes and platelets aggregation, while oxytocin fragment Pro-Leu-Gly-NH2 inhibited only erythrocytes aggregation without changing of platelet aggregation. Conclusion. Investigation of phased peptides proteolysis may result in the development of new drugs for targeted correction of various disturbances. So it is of current interest to study the effects of C-terminal fragments of pituitary hormones on hemostasis.


1991 ◽  
Vol 261 (6) ◽  
pp. R1388-R1394 ◽  
Author(s):  
R. A. Galbraith ◽  
A. Kappas

Cobalt protoporphyrin (CoPP) in single subcutaneous doses produces prolonged weight loss in adult and aged male rats. The altered body weight level in treated animals is actively defended against starvation or overfeeding over prolonged time periods (greater than 50-100 days). The actions of CoPP on appetite and body weight regulation are biphasic, comprising an initial period of hypophagia, probably mediated centrally, until a particular body weight level is attained. Resumption of normal calorie intake follows, although lowered body weight levels are sustained, suggesting an additional action of the compound on peripheral substrate metabolism. Controlled decrements in body weight can be produced by repetitive low-dose CoPP treatment (e.g., 1 mumol/kg body wt weekly); low-dose regimens do not elicit altered hormonal homeostasis or aberrations in heme/cytochrome P-450 regulation that have been observed following larger doses (25-50 mumol/kg body wt) of the compound. CoPP may be a valuable probe with which to explore the role of heme-related molecules in the regulation of appetite and body weight.


1971 ◽  
Vol 51 (2) ◽  
pp. 241-NP ◽  
Author(s):  
H. H. FEDER

SUMMARY 5α-Androstan-17β-ol-3-one in its free or in its propionate form was injected systemically (125 μg/day/rat) into sexually experienced, adult, castrated, male rats. These compounds were ineffective in activating masculine behaviour patterns, despite having measurable effects on body weight, seminal vesicle weight and penile morphology. The propionate form also had strong anti-gonadotrophic properties, since when it was injected for 6 days into intact, immature, male rats it significantly reduced testicular weight. In contrast, testosterone propionate (125 μg/day/rat) restored male sexual behaviour to the levels found before castration when injected systemically. Testosterone propionate also affected body weight, seminal vesicle weight, penile morphology and the testicular weight of immature males. These effects may have been due in part to conversion of testosterone to 5α-androstan-17β-ol-3-one, but this metabolic step does not seem to be obligatory for activation of male sexual behaviour in rats.


1976 ◽  
Vol 83 (1) ◽  
pp. 190-200 ◽  
Author(s):  
H. L. Verjans ◽  
K. B. Eik-Nes

ABSTRACT Testes of adult, male rats were exposed to a total dose of 1500 R of X-irradiation. Testicular weight decreased from day 8 after X-ray treatment. This decrease was, however, preceded by an increment of the testis weight on day 4 following treatment. X-ray treatment of testes was associated with significant increases in serum FSH. Testicular irradiation had, however, no effect on ventral prostate and seminal vesicles weights. Serum testosterone increased only on day 1, 2 and 4 after irradiation, while serum LH levels tended to increase from day 8 post-irradiation. These changes were not significant, however, when compared with non-irradiated controls. At 7, 13 and 20 days following 1500 R of bilateral, testicular X-irradiation, the hypothalamic-pituitary unit was still capable of responding to exogenous gonadotrophin releasing factor. Serum FSH may in male rats be regulated at least partly by circulating steroids of testicular origin and partly by an unknown factor of non-interstitial cell nature.


2020 ◽  
Vol 13 (2) ◽  
pp. 125-136
Author(s):  
Mohammad Alwan ◽  
Baraa Al-Okialy

The present study was aimed to investigate the role of alpha-lipoic acid ( ALA) as an antioxidant against in ameliorating histological disorders of pituitary- testicular axis- induced by hydrogen peroxide (H2O2) in adult Wistar rats. Forty adult male rats were randomly divided into four equal groups (10 rats /group) and were handled daily as follows for 56 days: Control group ( C) were intubated distilled water and received ordinary tap water; group T1 were intubated 60mg/kg B.W of ALA and received ordinary tap water; group T2 were administered H2O2 in tap water at a concentration of 0.05%, while group T3 were intubated 60mg/kg B.W of ALA and received ordinary tap water containing 0.05% H2O2. At the end of the experiment, body weights were recorded, then pituitary and testes were excised for histopathological study and testicular weight was recorded too. Rats administered H2O2 showed a significant decrease in testes weight to body weight ratio accompanied with major histopathological changes of the testes in comparison with other groups including; a significant decrease in the diameter of seminiferous tubules, high of germinal epithelial cell and degenerative changes with incomplete spermatogenesis. Besides, a significant decrease in the number of Leydig's cells in comparison with other experimental groups. Furthermore, pituitary gland of group T2 manifested a severe histological alteration in architecture characterized by atrophy with marked necrotic and degenerative changes. Whereas, rats administered ALA (group T3) shows an improvement of histological changes of pituitary and testicular tissues induced by hydrogen peroxide. In conclusion, the results indicated that alpha-lipoic acid mitigated pituitary-testicular dysfunctions induced by H2O2 through its antioxidant effects via scavenging free radicals.


1989 ◽  
Vol 120 (2) ◽  
pp. 269-273 ◽  
Author(s):  
A. López-Calderón ◽  
C. Ariznavarreta ◽  
M. D. Calderón ◽  
J. A. F. Tresguerres ◽  
M. I. Gonzalez-Quijano

ABSTRACT The response of prolactin to chronic stress in intact, adrenalectomized and adrenomedullectomized male rats was studied. Immobilization stress in intact animals induced a significant increase in plasma concentrations of prolactin after 20 and 45 min and a significant decrease when the rats were submitted to chronic restraint (6 h daily for 4 days). Five weeks after adrenomedullectomy, plasma prolactin and corticosterone responses to chronic stress were not modified. In contrast, the inhibitory effect of chronic stress on prolactin secretion was totally suppressed by adrenalectomy. When treated with dexamethasone during the 4 days of restraint, adrenalectomized stressed rats showed similar plasma concentrations of prolactin to the intact stressed rats. These data indicate that the adrenal cortex is able to play an inhibitory role on prolactin secretion during stress only through a prolonged release of glucocorticoids. Journal of Endocrinology (1989) 120, 269–273


1972 ◽  
Vol 31 (1) ◽  
pp. 95-101 ◽  
Author(s):  
Earl X. Freed ◽  
Norman Hymowitz

Two experiments with 43 Charles River (cd) male rats investigated the effects of schedule, percent body weight, and magnitude of reinforcer on the acquisition of schedule-induced polydipsia. A leaner reinforcement schedule induced greater polydipsia as did two non-schedule variables, reduced body weight and small magnitude of reinforcer. These findings, related to contemporary theories of schedule-induced polydipsia, emphasize the role of non-schedule variables in this behavior.


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