妊娠維持・胎児発育・分娩発来に及ぼす各種ステロイドホルモンの動態

抄録

Dependence of outset, maintenance of gravidity and onset of labor on different kinds of steroid hormones has long been the focus of debate with the underlying control mechanism of these hormones in question remaining left unestablished still in these days.
Of author's particular concern in this paper was the two-sided aspect of steroid functions. In fact, the steroid may stimulate mother's organ, fetus and placenta to produce much amount of steroid hormone throughout gravidic interval, while at the same time it may control the two contradictory processes, namely the maintenance of gravity and onset of labor through one and the same route. With a view to solve the complexity referred to above an effort has been made through a series of experiments particularity in the term of :
1. Dependent of a system capable to simultaneously determine concentrations of a variety of steroid hormones using the high performance liquid chromatography (HPLC);
2. Profile-analysis to be made on behavior of different kinds of steroids observable over gravidic interval under a support of HPLC system;
3. Behavior of different kinds of hemogenic hormones subsequent to an active DHAS loading in both group with- and without labor pains;
4. Influence of DHAS and gestation on activity of 11β hydroxy steroid dehydrogenase in placenta; Some of the results brought by these experiments, which are of some value to speculate on the mechanism of labor-onset and growth of fetus, may be summarized below in line with the preceding items :
1. The measuring system incorporating HPLC made it possible to determine 8 kinds of steroid hormones under systems of C19 and C21 readily in approx. 45 min., even when pretreatment is made involved in the procedure. It was also demonstrably verified that the system shows an acceptable sensitivity combined with a higher correlation with the RIA method.
2. Profile was successfully delineated of those steroids which would participate in controlling the labor pains inducing mechanism through a series of analytical works made on the behavior of steroid associated with the process of gravidism. With the approach of expected labor, it was seen that 5 kinds of steroid hormones comprising DHA, testosterone, pregnenolone, 20α OH-progesterone, and cortisol showed a marked increase. In contrast, androstenedione and progesterone begin to fall abruptly ever since several days proceeding the date of labor.
3. Gain of DHA, 17α OH-progesterone, due to DHAS-loading was clearly identified in the group with onset of labor pains. It was interesting to note that the group with labor pains showed a significant decrease of progesterone, while clearly in contrast the group without labor pains indicated a trend of its increase. These finding would play a purposive role in clearifing the significance of steroid in the occasion of parturition as a physiological process.
4. It is commonly agreed that cortisol play an important role to sustain fetus growth mechanism and safeguard of organism : and throughout the gravidic interval growth of fetus is kept controlled through a transformation of cortisol produced in much amount unplacenta into cortisone. By the way, the result from the present study revealed that DHAS produced by fetus would serve to suppress this transformation. These findings imply that a fetus can afford to control its growth selfsustaingly. In this context the foregoing findings would serve to explain the mechanism underlying the growth of fetus.
The forgoing results may be suggestive enough to clearfy the interaction of steroid hormones participating in the different processes such as maintenance of gravity, onset of labor and growth of fetus and further to offer general utility of the influence speculated on the theme of hormone-based mechanism of controlling gravidism.