Hoffmann J C
Neuroendocrinology. 1978;27(5-6):247-56. doi: 10.1159/000122817.
Adult female ARS/Sprague-Dawley rats were allowed to acclimatize to a a lighting schedule of 12L:12D (LD) for 5 weeks. At that time, half the animals were adrenalectomized, and all rats remained in LD for an additional 4 to 5 weeks. Subsequently, half of the control and half of the adrenalectomized rats were exposed to constant light (LL) for an additional 8 weeks, at which time all animals were sacificed. Operated rats with regenerated adrenal tissue, determined either by macroscopic examination or serum corticosterone assay (about 50% of the rats), were excluded from all data calculations. Acute disturbances of estrous cycle length were minor. The long-term effects revealed a significant increase in 5-day cycles among the adrenalectomized rats, although the majority of cycles recorded (80%) were still 4 days in length. None of the rats in LD showed spontaneous persistent estrus. Adrenalectomy did not affect the number of ova shed. When placed in LL, the adrenalectomized rats continued to cycle longer than the unoperated controls, but all rats showed persistent estrus (5 or more consecutive days of vaginal cornification) within 7--8 weeks. Adrenalectomized rats had significantly higher body weights than controls. Relative uterine weight was decreased in these animals in both lighting regimens but only reached statistical significance in LD. Ovarian weight, by contrast, was significantly increased among adrenalectomized rats in LD but was identical in both groups in LL. Adrenal weight of intact rats was not altered by LL. Since estrous cycles can continue for at least 6 months in the absence of the adrenal gland, the persistent estrus that occurs in LL is not merely due to the loss of a diurnal rhythm of corticosteroids. Indeed, when adrenalectomized rats are placed in LL, they continue to show estrous cycles longer than do intact rats. Adrenalectomy does appear to increase the length of the cycle in some animals, and the hormonal basis for this warrants further study.
成年雌性ARS/斯普拉格-道利大鼠被允许适应12小时光照：12小时黑暗（LD）的光照周期5周。那时，将一半的动物进行肾上腺切除术，所有大鼠在LD条件下再饲养4至5周。随后，将一半的对照大鼠和一半的肾上腺切除大鼠再暴露于持续光照（LL）8周，此时所有动物均被处死。通过宏观检查或血清皮质酮测定确定有再生肾上腺组织的手术大鼠（约占大鼠的50%）被排除在所有数据计算之外。发情周期长度的急性紊乱较小。长期影响显示，肾上腺切除大鼠的5天周期显著增加，尽管记录的大多数周期（80%）长度仍为4天。LD条件下的大鼠均未出现自发性持续发情。肾上腺切除术不影响排卵数量。置于LL条件下时，肾上腺切除大鼠的发情周期持续时间仍长于未手术的对照大鼠，但所有大鼠在7-8周内均出现持续发情（阴道角化连续5天或更长时间）。肾上腺切除大鼠的体重显著高于对照大鼠。在两种光照方案下，这些动物的相对子宫重量均降低，但仅在LD条件下达到统计学显著性。相比之下，LD条件下肾上腺切除大鼠的卵巢重量显著增加，但在LL条件下两组相同。完整大鼠的肾上腺重量不受LL影响。由于在没有肾上腺的情况下发情周期至少可以持续6个月，因此LL条件下出现的持续发情不仅仅是由于皮质类固醇昼夜节律的丧失。事实上，当肾上腺切除大鼠置于LL条件下时，它们的发情周期持续时间仍长于完整大鼠。肾上腺切除术似乎确实会增加一些动物的周期长度，其激素基础值得进一步研究。
