Azain M J, Hausman D B, Kasser T R, Martin R J
Department of Animal and Dairy Science, University of Georgia, Athens 30602, USA.
Am J Physiol. 1995 Jul;269(1 Pt 1):E137-44. doi: 10.1152/ajpendo.1995.269.1.E137.
The objective of the present study was to determine whether exogenous somatotropin (STH) administration in conjunction with feed restriction could alter the composition of gain in the obese rat. Five-week-old female lean and obese Zucker rats were assigned to the following treatments for 6 wk: ad libitum fed (AL), restricted (approximately 75% of AL lean), and restricted with STH (2 mg STH/day). Growth rate was decreased in restricted groups and was normalized to that of the AL lean group in restricted rats treated with STH. In lean rats, restriction decreased protein accretion. Restriction plus STH treatment decreased lipid accretion but increased protein accretion and body weight gain compared with the AL lean group. As expected, feed restriction reduced body size in obese rats, but carcass lipid was maintained at 44%, a level similar to that of the AL obese rats. Lipid accretion rate was decreased with restriction in obese rats and was further reduced, to a level similar to that of the lean group, in the obese rats that were restricted and treated with STH. Protein accretion was decreased in the restricted obese group but was normalized in those treated with STH to a level similar to that in the AL lean group. Basal rates of lipolysis in isolated adipocytes were not affected by STH. However, STH treatment normalized the responsiveness of cells from the obese rats to stimulation of lipolysis by isoproterenol. The results demonstrate that a combination of caloric restriction and STH was effective in normalizing body weight and composition of gain in the obese Zucker rat.
本研究的目的是确定外源性生长激素（STH）与限食联合使用是否会改变肥胖大鼠增重的组成。将5周龄的雌性瘦型和肥胖型 Zucker 大鼠分配到以下处理组，为期6周：自由采食（AL）、限食（约为AL组瘦鼠采食量的75%）和限食并注射STH（2毫克STH/天）。限食组大鼠的生长速率降低，而注射STH的限食大鼠的生长速率恢复到AL组瘦鼠的水平。在瘦鼠中，限食降低了蛋白质的蓄积。与AL组瘦鼠相比，限食加STH处理降低了脂肪蓄积，但增加了蛋白质蓄积和体重增加。正如预期的那样，限食降低了肥胖大鼠的体型，但胴体脂肪维持在44%，与AL组肥胖大鼠的水平相似。肥胖大鼠限食后脂肪蓄积率降低，限食并注射STH的肥胖大鼠脂肪蓄积率进一步降低，降至与瘦鼠组相似的水平。限食肥胖组的蛋白质蓄积减少，但注射STH的大鼠蛋白质蓄积恢复正常，达到与AL组瘦鼠相似的水平。STH对分离脂肪细胞的基础脂肪分解率没有影响。然而，STH处理使肥胖大鼠细胞对异丙肾上腺素刺激脂肪分解的反应恢复正常。结果表明，热量限制和STH联合使用可有效使肥胖 Zucker 大鼠的体重和增重组成恢复正常。
