Buntin J D, Hnasko R M, Zuzick P H
Department of Biological Sciences, University of Wisconsin-Milwaukee, 53201, USA.
Physiol Behav. 1999 Apr;66(2):255-61. doi: 10.1016/s0031-9384(98)00288-1.
Prolactin (PRL) strongly stimulates feeding activity and body weight gain in ring doves, and of the brain loci tested to date, the ventromedial hypothalamus (VMH) is the most effective site of PRL action in promoting these changes. To determine if the VMH is essential for this response, we examined the effects of VMN destruction on spontaneous feeding and on changes in food intake induced by intracerebroventricular (i.c.v.) injections of PRL. Male birds were selectively destroyed by radiofrequency lesions (n = 6). A group of sham-lesioned males (n = 6) served as controls. Lesioned birds exhibited a transient increase in food intake that peaked around the seventh postoperative day and declined to baseline levels by day 12. In contrast to this pattern, body weights of lesioned birds increased in parallel with food intake, but remained elevated throughout the 3-week postoperative period. During the peak period of hyperphagia in the lesioned group, food intake and body weight increases were two to three times greater in lesioned birds than in controls. After postoperative feed intake had stabilized, each bird received 5 daily i.c.v. injections of ovine PRL. Food intake and body weight increased dramatically in both groups in response to PRL treatment, and no group differences were observed in response to magnitude. We conclude that VMH destruction strongly perturbs feeding and body weight regulation in doves. However, VMH integrity is not essential for the expression of PRL-induced hyperphagia.
催乳素（PRL）能强烈刺激斑鸠的摄食活动和体重增加，在迄今为止所测试的脑区中，腹内侧下丘脑（VMH）是PRL促进这些变化作用最有效的部位。为了确定VMH对这种反应是否至关重要，我们研究了破坏VMN对自发摄食以及脑室内（i.c.v.）注射PRL引起的食物摄入量变化的影响。通过射频损伤选择性地损毁雄性鸟类（n = 6）。一组假损伤雄性鸟类（n = 6）作为对照。损毁的鸟类在术后第七天左右食物摄入量出现短暂增加并达到峰值，到第12天降至基线水平。与这种模式相反，损毁鸟类的体重随着食物摄入量的增加而平行增加，但在术后3周内一直保持升高。在损毁组的摄食亢进高峰期，损毁鸟类的食物摄入量和体重增加量是对照组的两到三倍。术后采食量稳定后，每只鸟每天接受5次脑室内注射绵羊PRL。两组对PRL治疗的反应均为食物摄入量和体重显著增加，且在反应程度上未观察到组间差异。我们得出结论，VMH损毁会严重扰乱鸽子的摄食和体重调节。然而，VMH的完整性对于PRL诱导的摄食亢进的表达并非必不可少。
