Kochan Z, Karbowska J, Swierczynski J
Department of Biochemistry, Medical University of Gdansk, Poland.
J Physiol Pharmacol. 2006 Nov;57 Suppl 6:115-27.
Weight cycling is one of the widely used weight reduction strategies; however, the adverse effects of this method include regaining significant amounts of weight. The molecular mechanisms underlying weight gain following cycles of dietary deprivation and refeeding are still poorly understood. One of the possibilities is that repeated loss and gain of weight may promote fat deposition in adipose tissue. To test this hypothesis we investigated serum leptin levels and lipogenic enzyme activities in white adipose tissue (WAT) of male Wistar rats during 12 days of ad libitum feeding following multiple cycles of alternating food deprivation and refeeding. Rats subjected to eight cycles of food deprivation and refeeding (MFR group) showed significantly decreased circulating leptin levels when compared with control rats (nearly 50% decrease in leptin levels, P < 0.01). Throughout 12 days of ad libitum feeding, serum leptin levels increased modestly but remained significantly (24%, P < 0.05) lower than control levels. Fatty acid synthase (FAS) and malic enzyme (ME) activities (chosen as representatives of enzymes directly involved in fatty acid synthesis) were found to be considerably higher in WAT of MFR rats refed for 3 days in comparison to control rats, and remained elevated even after 12 days of refeeding. These observations suggest that the elevation of lipogenic enzyme activities induced by multiple cycles of dietary deprivation followed by refeeding persists for several days, markedly increasing the lipogenic capacity of adipose tissue, which, accompanied by a decrease in circulating leptin levels, may promote weight gain.
体重循环是广泛使用的减肥策略之一；然而，这种方法的不良影响包括大量体重反弹。饮食限制和再喂养循环后体重增加的分子机制仍知之甚少。一种可能性是，体重的反复增减可能会促进脂肪在脂肪组织中的沉积。为了验证这一假设，我们研究了雄性Wistar大鼠在多次交替禁食和再喂养循环后的12天自由进食期间，白色脂肪组织（WAT）中的血清瘦素水平和脂肪生成酶活性。与对照大鼠相比，经历八次禁食和再喂养循环的大鼠（MFR组）的循环瘦素水平显著降低（瘦素水平降低近50%，P < 0.01）。在12天的自由进食期间，血清瘦素水平适度升高，但仍显著低于对照水平（降低24%，P < 0.05）。与对照大鼠相比，再喂养3天的MFR大鼠的白色脂肪组织中脂肪酸合酶（FAS）和苹果酸酶（ME）活性（被选为直接参与脂肪酸合成的酶的代表）显著更高，并且即使在再喂养12天后仍保持升高。这些观察结果表明，多次饮食限制后再喂养诱导的脂肪生成酶活性升高持续数天，显著增加了脂肪组织的脂肪生成能力，这伴随着循环瘦素水平的降低，可能会促进体重增加。
