Somatostatin Agonist Pasireotide Promotes a Physiological State Resembling Short-Day Acclimation in the Photoperiodic Male Siberian Hamster (Phodopus sungorus)
Somatostatin Agonist Pasireotide Promotes a Physiological State Resembling Short-Day Acclimation in the Photoperiodic Male Siberian Hamster (Phodopus sungorus)
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DOI：
10.1111/jne.12289
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发表时间：
2015-07-01
影响因子：
3.2
通讯作者：
Barrett, P.
中科院分区：
文献类型：
--
作者：
Dumbell, R. A.;Scherbarth, F.;Barrett, P.
季节性哺乳动物的生长时间与食物供应密不可分。西伯利亚仓鼠（Photopus sungorus）就是一个例子，它利用光周期的年周期来优化能量消耗，以预测食物资源的季节性波动。在秋季，能量消耗通过生理适应逐渐减少，包括体重减少30%，包括脂肪和瘦肉组织的减少。然而，这种适应的机制基础仍然是无法解释的。我们假设，生长激素（GH）是一个可能的候选人，以支持这些可逆的变化体重。在长日照（LD）光周期条件下，给予雄性仓鼠帕瑞肽（一种开发用于治疗肢端肥大症的长效生长抑素受体激动剂）可使体重减轻。这包括瘦肉和脂肪质量的减少，包括肾脏、睾丸和棕色脂肪组织，通常见于短日照（SD）饲养的仓鼠。此外，当对从SD转换为LD的仓鼠给药时，与溶剂处理的仓鼠相比，帕瑞肽延缓了体重增加。帕瑞肽没有改变光周期介导的下丘脑能量平衡基因表达的变化，但改变了室周核Srif mRNA表达和弓状核Ghrh mRNA表达的表达，这与GH反馈减少一致，同时血清胰岛素样生长因子-1减少。相反，SD仓鼠的GH治疗增加了体重，包括肝脏和肾脏的质量增加。总之，这些数据表明GH轴在确定西伯利亚仓鼠的季节性体重中的作用。
The timing of growth in seasonal mammals is inextricably linked to food availability. This is exemplified in the Siberian hamster (Phodopus sungorus), which uses the annual cycle of photoperiod to optimally programme energy expenditure in anticipation of seasonal fluctuations in food resources. During the autumn, energy expenditure is progressively minimised by physiological adaptations, including a 30% reduction in body mass, comprising a reduction in both fat and lean tissues. However, the mechanistic basis of this adaptation is still unexplained. We hypothesised that growth hormone (GH) was a likely candidate to underpin these reversible changes in body mass. Administration of pasireotide, a long-acting somatostatin receptor agonist developed for the treatment of acromegaly, to male hamsters under a long-day (LD) photoperiod produced a body weight loss. This comprised a reduction in lean and fat mass, including kidneys, testes and brown adipose tissue, typically found in short-day (SD) housed hamsters. Furthermore, when administered to hamsters switched from SD to LD, pasireotide retarded the body weight increase compared to vehicle-treated hamsters. Pasireotide did not alter photoperiod-mediated changes in hypothalamic energy balance gene expression but altered the expression of Srif mRNA expression in the periventricular nucleus and Ghrh mRNA expression in the arcuate nucleus consistent with a reduction in GH feedback and concurrent with reduced serum insulin-like growth factor-1. Conversely, GH treatment of SD hamsters increased body mass, which included increased mass of liver and kidneys. Together, these data indicate a role for the GH axis in the determination of seasonal body mass of the Siberian hamster.