Day J R, Lapolt P S, Lu J K
Department of Obstetrics/Gynecology, UCLA School of Medicine 90024.
Biol Reprod. 1991 May;44(5):786-90. doi: 10.1095/biolreprod44.5.786.
Regularly cyclic, middle-aged female rats exhibit a decreased incidence of fertility, and those females that are fertile produce smaller litters. This decreased litter size is directly related to a reduced number of normal blastocysts available for implantation. Recent evidence indicates that embryonic abnormalities in middle-aged rats become apparent as early as Day 2 of pregnancy. Inasmuch as the semicircadian secretion of prolactin (PRL) is essential for the rescue of corpora lutea during early gestation and luteal production of progesterone (P) and estradiol (E2) in sufficient quantities is obligatory for embryonic development and implantation, the present study examined the profiles of plasma PRL, P, and E2 during the first 3 days of pregnancy in both young and middle-aged rats and assessed the embryonic development in these same animals. Regularly cyclic, middle-aged (9-11 mo) and young (4-5 mo) rats were cannulated via the right jugular vein on Diestrus Day 2 and mated with fertile males on proestrus. The next morning, sperm in the vaginal lavage confirmed mating, and that day was designated Day 1 of pregnancy. Beginning at 1400 h on Day 1 and continuing to 2400 h on Day 2, serial blood samples were taken at 2-h intervals for PRL assay. In the first experiment, samples were also collected at 8-h intervals during Days 1-3 for measurement of plasma P.(ABSTRACT TRUNCATED AT 250 WORDS)
规律发情的中年雌性大鼠生育能力下降，那些能生育的雌性大鼠产仔数较少。产仔数减少直接与可用于着床的正常囊胚数量减少有关。最近的证据表明，中年大鼠的胚胎异常早在怀孕第2天就很明显。由于在妊娠早期，催乳素（PRL）的半昼夜分泌对于黄体的维持至关重要，并且黄体分泌足够量的孕酮（P）和雌二醇（E2）对于胚胎发育和着床是必不可少的，因此本研究检查了年轻和中年大鼠怀孕前3天血浆PRL、P和E2的变化情况，并评估了这些动物的胚胎发育。在动情周期第2天，通过右颈静脉对规律发情的中年（9 - 11月龄）和年轻（4 - 5月龄）大鼠进行插管，并在发情前期与可育雄性大鼠交配。次日早晨，阴道灌洗中有精子则确认交配成功，当天被定为怀孕第1天。从第1天1400时开始，至第2天2400时，每隔2小时采集系列血样用于PRL检测。在第一个实验中，在第1 - 3天还每隔8小时采集样本用于测定血浆P。（摘要截断于250字）
