Effects of melatonin in vivo upon luteinizing hormone and prolactin releases induced by opiate receptor antagonists in adult male rats.

The effects of melatonin on LH and PRL releases induced by treatment with naloxone, naloxone methyliodide and nalmefene were studied in adult male rats. Subcutaneous melatonin injection (1.4 mg/Kg) had no effect on LH secretion, but caused an inhibition effect (84%) on LH release induced by naloxone (2.

Stimulatory effect of perhexiline maleate on the basal and LHRH-stimulated luteinizing hormone release from rat pituitary cell aggregates in vitro.

Perhexiline maleate (PM) is an anti-anginal agent of amphiphilic character involved in lipidosis disorders. Experiments were carried out to study PM action on LH release from rat anterior pituitary cell aggregates. PM caused significant and dose-dependent increases of basal LH release when the aggregates had been previously treated with PM for 20 min, then incubated for 30 min with the same concentration of drug after renewal of the culture medium.

Effect of naloxone and beta-casomorphin on the hypothalamic-pituitary-luteinizing hormone axis in vitro.

The effect of naloxone and beta-casomorphin on luteinizing hormone (LH) release from pituitary cell aggregates, obtained by three-dimensional culture, with or without mediobasal hypothalamic fragments was studied in vitro. Short-term naloxone perifusion at a concentration of 10(-5)M did not modify either basal or LHRH-stimulated LH release from the pituitary cell aggregates. In contrast, a 12-min naloxone perifusion at the same concentration caused an increase in LH release in the mediobasal hypothalamic-pituitary cell aggregate axis.

[Biological effects in the female rat of active mixed immunization against estradiol and testosterone].

Active simultaneous immunization of female rats against 17 beta-estradiol and testosterone induced formation of ovarian haemorrhagic and cystic follicles. A 2-fold increase in serum luteinizing hormone but any differences in prolactin levels were noted.

[In vitro effect of 5 alpha-androstane-3 beta, 17 beta diol on the liberation of follicle stimulating hormone (FSH) induced by LH-RH].

A continuous flow incubation (perifusion) was used to examine the effect of 5 alpha-androstane-3 beta, 17 beta diol 3 beta diol) on the release of FSH induced by LH-RH. Over a 3 h-period the 3 beta diol exerts inhibitory effects on male and female pituitaries at high dose (1 microgram/ml) and only on male pituitaries at low dose (100 ng/ml).