Mauer M M, Bartness T J
Department of Psychology, Georgia State University, Atlanta 30303.
Am J Physiol. 1994 Mar;266(3 Pt 2):R870-8. doi: 10.1152/ajpregu.1994.266.3.R870.
Siberian hamsters exhibit seasonal fluctuations in body weight (fat). Initial exposure to a short photoperiod results in body fat loss that reverses after approximately 22 wk of short-day exposure. The purpose of this study was to determine whether Siberian hamsters are able to recover body fat after surgical reduction of total lipid stores and if so, whether this ability is photoperiod dependent and fat pad specific. Either the largest pair of internal fat pads, the epididymal white adipose tissue (EWAT) or one pair of two large external depots, the inguinal (IWAT) fat pads, were removed from male hamsters housed for 22 wk in a long (LD) or short (SD) photoperiod. Retroperitoneal fat pad (RWAT) mass was increased in LD EWAT- and IWAT-lipectomized hamsters. IWAT mass also was increased in the LD EWAT-lipectomized hamsters. Neither SD-lipectomized group compensated for body fat loss in any of the measured fat pads. Increased food intake was not necessary for total body fat recovery, but undereating partially may be responsible for the lack of recovery in SDs. The results of these experiments demonstrate a photoperiod-dependent ability of male Siberian hamsters to regulate total body fat after partial lipectomy. In addition, recovery involves a fat pad-specific compensatory response to partial lipectomy, rather than a general increase in lipid deposition in all fat depots.
西伯利亚仓鼠的体重（脂肪）呈现季节性波动。初次暴露于短光照周期会导致体脂减少，在短日照暴露约22周后这种情况会逆转。本研究的目的是确定西伯利亚仓鼠在手术减少总脂质储备后是否能够恢复体脂，如果可以，这种能力是否依赖于光照周期以及是否具有脂肪垫特异性。从饲养在长（LD）或短（SD）光照周期22周的雄性仓鼠中，切除最大的一对内部脂肪垫，即附睾白色脂肪组织（EWAT），或一对两个大的外部脂肪库，即腹股沟（IWAT）脂肪垫。在长日照EWAT和IWAT脂肪切除的仓鼠中，腹膜后脂肪垫（RWAT）质量增加。在长日照EWAT脂肪切除的仓鼠中，IWAT质量也增加。两个短日照脂肪切除组在任何测量的脂肪垫中均未补偿体脂损失。全身脂肪恢复并不需要增加食物摄入量，但食量不足可能部分导致了短日照组缺乏恢复。这些实验结果表明，雄性西伯利亚仓鼠在部分脂肪切除后具有依赖光照周期调节全身脂肪的能力。此外，恢复涉及对部分脂肪切除的脂肪垫特异性代偿反应，而不是所有脂肪库中脂质沉积的普遍增加。
