هسته شكمي - مياني هيپوتالاموس در ترشح هورمون هاي جنسي و پرولاكتين در موش صحرايي نر D2 نقش گيرنده هاي

The effects of D2 receptors of the ventromedial nucleus (VMN)of the hypothalamus on secretion of sex and prolactin hormones in male rats

Introduction: In this study, the regulatory role of the ventromedial nucleus (VMN) of the hypothalamus on pituitary gland secretion, was studied. We investigated the influence of D2 receptors of the VMN on serum levels of sex hormones and prolactin. Materials and Methods: 35 adult male rats, weighing between 280-320g, were selected and cannulae were implanted bilaterally into the VMN. After the recovery period, rats were divided into 5 groups: sul (injected 81.ig sulpiride), sham-s (injected vehicle), Bromo (injected 25 µg bromocriptin), sham b-operated (injected vehicle), S+B (injected sulpiride Bromcriptine). The drugs were injected daily into the VMN (0.5µl/min) for 7 days, 0.5 hours after the last injection, the animals were decapitated and blood samples were collected. Serum levels of sex hormone and prolactin were measured by RIA method. Results: The results of this study indicate that sulpiride and (or) Bromocriptine cannot change the serum level of prolactin, testosterone and estradiol but sulpiride increases serum level of progesterone and decreases the estradiol progesterone ratio, Bromocriptin showed the reverse effects. Conclusion: We conclude that D2 receptors of VMN have a role in the regulation of sex hormone secretion.