Carro E, Señaris R, Considine R V, Casanueva F F, Dieguez C
Dept. of Physiology, University of Santiago, Santiago de Compostela, Spain.
Endocrinology. 1997 May;138(5):2203-6. doi: 10.1210/endo.138.5.5238.
Leptin, the product of the ob gene, is a recently discovered hormone secreted by adipocytes that regulates food intake and energy expenditure. Growth hormone (GH) secretion is markedly influence by body weight being markedly suppressed in obesity and underweight. The aim of the present study was to study whether leptin can act as a metabolic signal connecting the adipose tissue with the growth hormone axis. We administered leptin antiserum (10 ul, i.c.v.) or normal rabitt serum (NRS; 10 ul, i.c.v.) to freely moving fed rats. Furthermore we assessed the effect of leptin administration (10 ug, i.c.v.) on fed and fasted rats. Spontaneous GH secretion was assessed over 6 hours with blood samples taken every 15 min. Administration of leptin antiserum led to a decrease in spontaneous GH secretion as assessed by the area under the curve (AUC) (168+/-72 ng/ml/6h) in comparison to NRS-treated rats (813+/-179 ng/ml/6h, p<0.01). While leptin administration (10 ug/rat; i.c.v.) to normal fed rats did not modify spontaneous GH secretion, leptin administration to fasted rats led to a reversal of the inhibitory effect exerted by fasting on GH secretion (AUC, 1650+/-351 ng/ml/6h vs 77+/-32 ng/ml/6h, p<0.01). This data suggests that leptin is a metabolic signal that regulates GH secretion.
瘦素是ob基因的产物，是一种最近发现的由脂肪细胞分泌的激素，它可调节食物摄入和能量消耗。生长激素（GH）的分泌受体重的显著影响，在肥胖和体重过轻时会受到明显抑制。本研究的目的是探讨瘦素是否可作为连接脂肪组织与生长激素轴的代谢信号。我们给自由活动的进食大鼠脑室内注射瘦素抗血清（10微升）或正常兔血清（NRS；10微升）。此外，我们评估了给进食和禁食大鼠脑室内注射瘦素（10微克）的效果。每隔15分钟采集血样，在6小时内评估自发性GH分泌情况。与接受NRS处理的大鼠（813±179纳克/毫升/6小时）相比，注射瘦素抗血清导致自发性GH分泌曲线下面积（AUC）下降（168±72纳克/毫升/6小时，p<0.01）。给正常进食大鼠脑室内注射瘦素（10微克/只）并未改变自发性GH分泌，而给禁食大鼠注射瘦素则导致禁食对GH分泌的抑制作用逆转（AUC，1650±351纳克/毫升/6小时对77±32纳克/毫升/6小时，p<0.01）。这些数据表明，瘦素是一种调节GH分泌的代谢信号。
