Galanin regulation of LH release in male rats.

The present study examines the role of cerebroventricular administered (IIIrd ventricle) galanin on LHRH and LH release in adult and immature male rats. In both age groups, galanin stimulated LHRH synthesis and release from the hypothalamus, leading to a higher release of pituitary LH which in turn increased plasma LH levels. Galantide, a galanin receptor blocker, on the other hand, drastically reduced hypothalamic LHRH and plasma LH while increasing pituitary LH. In vitro incubation of anterior pituitary cells with galanin followed by LHRH resulted in increased release of pituitary LH but not by galanin alone. Galantide exhibited no such effect either alone or with LHRH. These results indicate that galanin is an important regulator for both hypothalamic LHRH and hypophysial LH and its role is independent of age in the case of male rats.

Galanin stimulates hCG induced testicular steroidogenesis in adult but not in immature male rats.

The present study was undertaken to understand the role of galanin on testosterone secretion. Leydig cells from adult (60-80 days old) and immature (21-30 days old) rat testis were incubated with galanin (100 nM), galantide (100 nM) and Human Chorionic Gonadotropin (hCG, 25 I.U.) alone or in combinations and testosterone release was measured. It was observed that in adults, galanin failed to alter the basal testosterone release from the dispersed Leydig cells but potentiated the hCG induced testosterone release significantly. While galantide, prevented this galanin potentiating effect, but it did not alter the hCG alone induced testosterone release. On the other hand, the Leydig cells obtained from immature male rats were sensitive to hCG alone but not to galanin or galantide, both of which failed to alter the hCG induced testosterone release from these cells. Based on these results it can be postulated that galanin's role at the level of the male gonad is age dependent since its potentiating effects on hCG induced testosterone release were visible only in the adult and not in the immature male rats.

Effect of beta-endorphin and naloxone on rat testicular steroidogenesis.

With a view to examine the possibility of a direct role of opioids in the regulation of testicular steroidogenesis, the following in vivo and in vitro experiments were conducted in male rats of different age groups. Intratesticular (i.t.) injections of beta-endorphin (beta-EP) and its antagonist naloxone (nal) were given bilaterally to adult (80-100 days), peripubertal (40 days) and juvenile (20 days) rats and blood was collected at different time intervals up to 90 min and assayed for testosterone (T). beta-EP suppressed T levels in all age groups of rats while naloxone stimulated T secretion only in adult rats. In another experiment, adult rats were also injected with 60 IU of hCG (sc) after 30 min. of beta-EP/nal treatment. Naloxone induced a greater rise in T in the presence of hCG while beta-EP blocked the hCG induced rise in testosterone. In the in vitro sets of experiments, isolated interstitial cells from testes of adult, 40 and 20 days old rats were incubated for 4 hr with hCG (25 IU), beta-EP (0.5ng) and nal (5.0ng) alone or in combinations. Naloxone alone was ineffective although it significantly enhanced hCG stimulated T release. beta-EP decreased both basal and hCG stimulated T release. Based on these results we postulate that opioids may influence steroidogenesis possibly by altering the response of interstitial cells to LH.

Effect of season and photoperiod on the follicle stimulating.

Annual changes in and photoperiodic influence oh the weight of gonads, a parameter of gonadal activity, are much smaller in female birds than in males. Effect of season and photoperiod on the follicle-stimulating hormone receptors in the testis or ovary was studied using a subtropical weaver finch. The number of follicle-stimulating hormone binding sites per unit testicular weight showed a peak in the non-breeding phase; while the total number of binding sites per two testes was maximal in the breeding phase and minimal in the regressive phase. In contrast, seasonal changes in follicle-stimulating hormone binding sites in the ovary were less marked. Exposure to short-day during the breeding phase induced marked decreases in the numbers of binding sites per unit testicular weight and per two testes. These numbers markedly increased after transfer to long-day during the non-breeding phase. However, there was no significant effect of short-day or long-day exposure on follicle-stimulating hormone binding sites in the ovary. These results suggest that photoperiod is an effective environmental factor in the regulation of follicle-stimulating hormone receptors in the testis and the effect is manifested by pronounced changes in the testicular weight during annual breeding cycle.

Anti-inflammatory and analgesic properties of four amino-acids.

Orally administered L-isoleucine, DL-isoleucine and L-leucine exhibited anti-inflammatory activity in many test models of inflammation except formaldehyde-induced inflammation. L-beta-phenylalanine inhibited carrageenan-induced oedema only. L-isoleucine also exhibited prolonged analgesic effect while DL-isoleucine had a short lasting effect. The amino-acids produced no gastric ulceration or overt acute toxicity in doses which effectively suppress inflammation. Anti-inflammatory activity seems to be related with interference with the action and/or synthesis of prostaglandins and deserves further intensive study.