Hanai Miho, Esashi Takatoshi
Department of Nutrition and Life Science, Kanagawa Institute of Technology.
J Nutr Sci Vitaminol (Tokyo). 2013;59(6):552-9. doi: 10.3177/jnsv.59.552.
The purpose of this study was to determine whether the effects of dietary protein on sexual organ development were different in mice and rats kept under constant darkness. Four-week-old mice (ICR strain) and rats (F344 strain) were kept under constant darkness (D) or normal lighting (N; 12-h light/dark cycle) for 4 wk. The dietary protein level was 9% casein with the addition of 0.135% cystine (9PC) or without it (9P); other components of the diet were based on the AIN-93G diet. The testes and epididymides weights (g/100 g BW) of the rats given the 9P diet in the D-group were lower than those of the rats given the 9P diet in the N-group. In the mice, lighting conditions and diet did not affect testes or epididymides weights. Body weight and food intake in the rats were affected by diet, and these values were lower in the 9P diet group; however, body weight and food intake in the mice was not affected by diet. The serum albumin concentration in the rats was lower in the 9P diet group, while that of the mice was lower in the 9PC diet group. In the rats kept under constant darkness, a diet lacking in cystine accelerated the suppression of sexual organ development and decreased serum albumin concentration, but this diet had no such effects on the mice. The finding that the effects of dietary protein were different in mice and rats suggests that protein requirements of mice are different from those of rats.
本研究的目的是确定在持续黑暗环境下饲养的小鼠和大鼠中，膳食蛋白质对性器官发育的影响是否存在差异。将4周龄的小鼠（ICR品系）和大鼠（F344品系）在持续黑暗（D）或正常光照（N；12小时光照/黑暗循环）条件下饲养4周。膳食蛋白质水平为添加0.135%胱氨酸的9%酪蛋白（9PC）或不添加胱氨酸的9%酪蛋白（9P）；饮食的其他成分基于AIN-93G饮食。D组中给予9P饮食的大鼠的睾丸和附睾重量（克/100克体重）低于N组中给予9P饮食的大鼠。在小鼠中，光照条件和饮食对睾丸或附睾重量没有影响。大鼠的体重和食物摄入量受饮食影响，9P饮食组的这些值较低；然而，小鼠的体重和食物摄入量不受饮食影响。9P饮食组大鼠的血清白蛋白浓度较低，而9PC饮食组小鼠的血清白蛋白浓度较低。在持续黑暗环境下饲养的大鼠中，缺乏胱氨酸的饮食加速了性器官发育的抑制并降低了血清白蛋白浓度，但这种饮食对小鼠没有此类影响。膳食蛋白质对小鼠和大鼠的影响不同这一发现表明，小鼠的蛋白质需求与大鼠不同。
