Leptin acts on metabolism in a photoperiod-dependent manner, but has no effect on reproductive function in the seasonally breeding Siberian hamster (Phodopus sungorus)
Leptin acts on metabolism in a photoperiod-dependent manner, but has no effect on reproductive function in the seasonally breeding Siberian hamster (Phodopus sungorus)
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DOI：
10.1210/en.141.11.4128
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发表时间：
2000-11-01
期刊：
影响因子：
4.8
通讯作者：
Loudon, ASI
中科院分区：
文献类型：
--
作者：
Atcha, Z;Cagampang, FRA;Loudon, ASI
瘦素可能在食欲调节和新陈代谢中发挥作用，但其生殖作用尚不清楚。在光周期的西伯利亚仓鼠中，肥胖、瘦素基因表达和新陈代谢的季节性变化与生殖的激活或抑制同步发生，类似于青春期。在这里，我们测试了瘦素分泌的季节性变化介导了生殖的光周期调节的假设。成年雄性西伯利亚仓鼠和去卵巢雌性西伯利亚仓鼠分别在长时间(LD，光照16h，黑暗8h)和短日照(SD：光照8h，黑暗16h)中饲养8周，并通过渗透压小泵注入重组小鼠瘦素(15µg/d)，连续2周。SD仓鼠体重和脂肪显著减少，血清瘦素和食物摄入量减少，脑下垂体LII浓度受到抑制。瘦素在两种光周期的一周治疗中都没有抑制食物的摄取，但显著减少了SD仓鼠的脂肪储备。无论性别或光周期，瘦素对垂体中的黄体生成素浓度均无显著影响，对男性的睾丸大小和睾酮浓度也无显著影响。这些结果表明，仓鼠对SD比LD对瘦素的反应更敏感，对食物摄入量和脂肪损失的影响可以在这个物种中分离出来。我们的数据表明，瘦素并不调节光周期的生殖变化。
Leptin may play a role in appetite regulation and metabolism, but its reproductive role is less clear. In photoperiodic Siberian hamsters, seasonal changes in fatness, leptin gene expression, and metabolism occur synchronously with activation or suppression of reproduction, analogous to puberty. Here, we test the hypothesis that seasonal changes in leptin secretion mediate the photoperiodic regulation of reproduction. Mature male and ovariectomized estrogen-treated female Siberian hamsters were kept in long (LD; 16 h of light, 8 h of darkness) or short days (SD: 8 h of light, 16 h of darkness) for 8 weeks, and recombinant murine leptin (15 mug/day) was infused for 2 weeks via osmotic minipumps. SD hamsters exhibited significant weight and fat losses, reduced serum leptin and food intake, and suppressed pituitary LII concentration. Leptin did not suppress food intake over the a-week treatment on either photoperiod, but significantly reduced fat reserves in SD hamsters. Leptin had no significant effect on pituitary LH concentrations in either sex or photoperiod or on testicular size and testosterone concentrations in males. These results suggest hamsters are more responsive to leptin on SD than on LD and that effects on food intake and fat loss can be dissociated in this species. Our data suggest that leptin does not mediate photoperiodic reproductive changes.