Welschen R, Osman P, Dullaart J, de Greef W J, Uilenbroek J T, de Jong F H
J Endocrinol. 1975 Jan;64(1):37-47. doi: 10.1677/joe.0.0640037.
Throughout a period of pseudopregnancy the peripheral blood levels of progesterone, oestradiol-17 beta, follicle-stimulating hormone (FSH) and luteinizing hormone (LH), as well as the size-distribution of ovarian antral follicles were estimated in the rat. The progesterone concentrations, as measured by a competitive protein-binding technique, exceeded metoestrous values (25 ng/ml plasma) from day 3 of pseudopregnancy onwards. The highest levels were found on days 6 and 8 (91 ng/ml). From day 8 onwards the levels decreased gradually but were still above metoestrous values on the day of pro-oestrus after pseudopregnancy. Concentrations of oestradiol-17 beta, as measured by radioimmunoassay, were within the range of those at metoestrus (about 5 pg/ml plasma) until day 10. Thereafter levels increased to a value of 57 pg/ml. Concentrations of FSH, measured by radioimmunoassay, were within the range of metoestrous values until day 10 (about 100 ngNIAMD-rat-FSH RP-1/ml serum), but declined to a level of 33 ng/ml on day 12. Concentrations of LH, measured by radioimmunoassay, were generally within the wide range of metoestrous values (9-60 ng NIAMD-rat-LH RP-1/ml serum), but concentrations found on days 4, 8 and 10 were significantly lower than those found on preceding or subsequent days. Histological determination of the number of follicles present in various volume-classes, showed an increase in antral follicles on days 1 and 2, comparable to the increase observed during metoestrus and dioestrus 1 of the normal cycle. There was no change in the follicles between days 3 and 10 and they resembled those of early dioestrus. Preovulatory growth had occurred by day 12. Injection of human chorionic gonadotrophin (HCG) on days 2, 4 or 6 showed that ovulation could be induced only in some of the larger follicles. On the basis of these results it is suggested that during pseudopregnancy the high progesterone levels present result in a decreased plasma LH level which is insufficient to cause full maturation of the follicles and to stimulate oestrogen secretion to the levels required for induction of an ovulatory surge of LH release.
在大鼠假孕期间，对其外周血中的孕酮、雌二醇 - 17β、促卵泡激素（FSH）和促黄体生成素（LH）水平以及卵巢窦状卵泡的大小分布进行了评估。采用竞争性蛋白结合技术测定的孕酮浓度，从假孕第3天起超过动情后期的值（25 ng/ml血浆）。在第6天和第8天发现最高水平（91 ng/ml）。从第8天起水平逐渐下降，但在假孕后动情前期当天仍高于动情后期的值。通过放射免疫测定法测定的雌二醇 - 17β浓度，直到第10天处于动情后期的范围内（约5 pg/ml血浆）。此后水平升至57 pg/ml。通过放射免疫测定法测定的FSH浓度，直到第10天处于动情后期的值范围内（约100 ngNIAMD - 大鼠 - FSH RP - 1/ml血清），但在第12天降至33 ng/ml。通过放射免疫测定法测定的LH浓度，一般处于动情后期较宽的值范围内（9 - 60 ng NIAMD - 大鼠 - LH RP - 1/ml血清），但在第4天、第8天和第10天发现的浓度明显低于前一天或后一天。对不同体积类别的卵泡数量进行组织学测定，结果显示在第1天和第2天窦状卵泡增加，与正常周期动情后期和动情间期1观察到的增加情况相当。在第3天至第10天卵泡没有变化，它们类似于早期动情间期的卵泡。到第12天已发生排卵前生长。在第2天、第4天或第6天注射人绒毛膜促性腺激素（HCG）表明，仅在一些较大的卵泡中可诱导排卵。基于这些结果表明，在假孕期间，高水平的孕酮导致血浆LH水平降低，这不足以使卵泡完全成熟并刺激雌激素分泌至诱导LH释放排卵高峰所需的水平。
