Chen H J, Targovnik J, McMillan L, Randall S
J Endocrinol. 1984 Apr;101(1):1-6.
Effects of age and naloxone on testicular function were studied in golden hamsters exposed to short photoperiods. Subjection of hamsters to short photoperiods of 6 h light: 18 h darkness for 6 weeks led to testicular regression in young adult (5-6 months) or middle-aged (11-12 months) golden hamsters but not in prepubertal hamsters of 1-2 months of age. The middle-aged hamsters had decreased testis width by week 4 of treatment and the young hamsters by week 5. Daily injection of naloxone at the time of 'lights on' partially prevented testicular regression in young and middle-aged hamsters but the extent of regression was significantly greater in the middle-aged animals. Plasma LH and FSH concentrations were significantly reduced in hamsters placed in short photoperiods regardless of age or testicular weight, while naloxone treatment significantly increased the LH concentrations in all age groups. Plasma beta-endorphin-like immunoreactivity was significantly increased by short photoperiod or older age. These results indicated that (a) the sensitivity of the testicular suppression to short photoperiod increases as a function of age, (b) naloxone, a specific opiate receptor blocker, can partially prevent short photoperiod-induced testicular regression and (c) ageing and short photoperiods increase beta-endorphin-like immunoreactivity. It is concluded that the opiate system may be involved in ageing and photoperiod regulation of reproductive function.
在暴露于短光照周期的金黄仓鼠中研究了年龄和纳洛酮对睾丸功能的影响。将仓鼠置于6小时光照：18小时黑暗的短光照周期6周，导致年轻成年（5 - 6个月）或中年（11 - 12个月）金黄仓鼠睾丸退化，但1 - 2个月龄的青春期前仓鼠未出现这种情况。中年仓鼠在治疗第4周时睾丸宽度减小，年轻仓鼠在第5周时减小。在“开灯”时每日注射纳洛酮可部分预防年轻和中年仓鼠的睾丸退化，但中年动物的退化程度明显更大。无论年龄或睾丸重量如何，处于短光照周期的仓鼠血浆促黄体生成素（LH）和促卵泡生成素（FSH）浓度均显著降低，而纳洛酮治疗显著增加了所有年龄组的LH浓度。短光照周期或老龄会使血浆β-内啡肽样免疫反应性显著增加。这些结果表明：（a）睾丸对短光照周期抑制的敏感性随年龄增加；（b）纳洛酮，一种特异性阿片受体阻滞剂，可部分预防短光照周期诱导的睾丸退化；（c）衰老和短光照周期会增加β-内啡肽样免疫反应性。得出的结论是，阿片系统可能参与生殖功能的衰老和光周期调节。
