Sahu A
Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine, PA 15261, USA.
Endocrinology. 1998 Feb;139(2):795-8. doi: 10.1210/endo.139.2.5909.
Leptin (OB protein) reduces food intake by acting at the hypothalamic level. The purpose of the present study was to identify potential targets of leptin signaling in the hypothalamus in ad-lib fed rats. Central administration of leptin (5 microg) for 3 days decreased food intake and body weight gain in association with a decrease in hypothalamic galanin (GAL), melanin-concentrating hormone (MCH), proopiomelanocortin (POMC) and neuropeptide Y (NPY) gene expression and with an increase in neurotensin (NT) gene expression. In pair-fed rats, NPY gene expression was increased and there was no change in either MCH, GAL, POMC or NT gene expression. This study identifies GAL, MCH, POMC and NT as non-NPY targets of leptin signaling and suggests that leptin's action on food intake and body weight is most likely mediated by inhibiting excitatory (e.g. NPY, MCH, GAL, POMC) and stimulating inhibitory (e.g., NT) signals in the feeding circuitry.
瘦素（OB蛋白）通过作用于下丘脑水平来减少食物摄入量。本研究的目的是确定自由进食大鼠下丘脑内瘦素信号的潜在靶点。连续3天向大鼠中枢注射瘦素（5微克）可减少食物摄入量和体重增加，同时下丘脑甘丙肽（GAL）、促黑素细胞激素（MCH）、阿黑皮素原（POMC）和神经肽Y（NPY）基因表达降低，而神经降压素（NT）基因表达增加。在配对喂养的大鼠中，NPY基因表达增加，而MCH、GAL、POMC或NT基因表达均无变化。本研究确定GAL、MCH、POMC和NT为瘦素信号的非NPY靶点，并表明瘦素对食物摄入和体重的作用很可能是通过抑制进食回路中的兴奋性信号（如NPY、MCH、GAL、POMC）和刺激抑制性信号（如NT）来介导的。
