Heap R B, Galil A K, Harrison F A, Jenkin G, Perry J S
Ciba Found Symp. 1977(47):127-57. doi: 10.1002/9780470720295.ch7.
The different ways in which the progesterone requirements of pregnancy are met in various species are reviewed here. Progesterone production expressed in terms of metabolic body weight lies within about one order of magnitude in several species (but not in the rat), whether the hormone is predominantly ovarian or placental in origin. Parturition is usually preceded by a decrease in the plasma concentration of progesterone and the evidence which suggests that a decrease in secretion involves enzyme induction is summarized. In the sheep a sequence of well-marked hormonal changes can be discerned--an increase in fetal cortisol secretion followed by a fall in placental progesterone and a rise in oestrogen and prostaglandin F2alpha secretion. This sequence has been interpreted in terms of hierarchical control theory which envisages a series of levels placed in a descending order of importance and in which there is a downward transmission of a signal from a higher level that modifies activity at a lower level. A dominant level in the hierarchy in the sheep and pig seems to be the fetal hypothalamus and pituitary, but in the rabbit the maternal hypothalamus, pituitary and ovary play a more dominant role.
本文综述了不同物种满足妊娠对孕酮需求的不同方式。以代谢体重表示的孕酮产量在几个物种（但大鼠除外）中大致处于一个数量级范围内，无论该激素主要来源于卵巢还是胎盘。分娩通常先于孕酮血浆浓度下降，本文总结了表明分泌减少涉及酶诱导的证据。在绵羊中，可以识别出一系列明显的激素变化——胎儿皮质醇分泌增加，随后胎盘孕酮下降，雌激素和前列腺素F2α分泌增加。这一序列已根据层次控制理论进行了解释，该理论设想了一系列按重要性降序排列的层次，其中存在从较高层次向下传递的信号，该信号会改变较低层次的活动。绵羊和猪等级体系中的主导层次似乎是胎儿下丘脑和垂体，但在兔子中，母体下丘脑、垂体和卵巢发挥着更主导的作用。
