Rowland D L, van der Schoot P
Department of Psychology, Valparaiso University, IN 46383, USA.
Physiol Behav. 1995 Sep;58(3):567-72. doi: 10.1016/0031-9384(95)00093-x.
Light-dark (LD) cyclicity contributes to a number of reproductive events in the rat, including estrus cyclicity, and the timing of parturition and postpartum estrus. Constant light (LL) disrupts the female's cyclicity, and fertility is typically diminished. To ascertain whether constant light similarly diminishes the fertility of postpartum females, LL and LD animals were compared over three successive pregnancies on several reproductive measures including parturition, postpartum estrus and spontaneous ovulation, the timing of estrus relative to parturition, and the number, body weights, and viability of offspring. While the 24 h pattern of parturition differed for LL and LD groups, postpartum estrus and ovulation occurred reliably in both groups. The LD group showed greater variation in the birth-estrus interval, the result of a delayed estrus in those females giving birth late in the light phase. The likelihood of spontaneous ovulation and overall successful reproduction was high for both groups. Thus, unlike the cycling female, the fertility of the postpartum female is relatively unaffected by constant light. As such, these findings suggest that LD cyclicity is not critical for postpartum ovulation and estrus.
明暗（LD）循环对大鼠的一些生殖活动有影响，包括发情周期、分娩时间和产后发情时间。持续光照（LL）会扰乱雌性大鼠的周期，生育能力通常会下降。为了确定持续光照是否同样会降低产后雌性大鼠的生育能力，对LL组和LD组动物在连续三次怀孕过程中的多项生殖指标进行了比较，这些指标包括分娩、产后发情和自发排卵、发情相对于分娩的时间，以及后代的数量、体重和存活率。虽然LL组和LD组的24小时分娩模式有所不同，但两组产后发情和排卵都能可靠地发生。LD组在出生至发情间隔上表现出更大的差异，这是由于在光照期后期分娩的雌性大鼠发情延迟所致。两组自发排卵和总体繁殖成功的可能性都很高。因此，与处于发情周期的雌性大鼠不同，产后雌性大鼠的生育能力相对不受持续光照的影响。因此，这些发现表明，LD循环对产后排卵和发情并不关键。
