Progesterone은 배양중인 생쥐 초기배아의 난할을 억제하는 효과를 나타내고 있는데 이의 기작을 밝히기 위하여 이 호르몬이 배아 세포들의 각종 대사작용에 미치는 영향을 조사하여 다음과 같은 결과를 얻었다. 1. Progesterone은 배아의 아미노산 흡수능 (uptake)을 증가시키었으나 동화능 (incorporation)을 연저히 감소시켰다. 2. Progesterone은 핵산 전구물질들 (uridine과 thymidine)의 흡수능과 동화능을 모두 저하시켰다. 본 실험의 결과로 미루어 Progesterone은 배아 세포들의 단백질, RNA 그리고 DNA 등의 고분자화합물의 합성을 저해하여 배아의 난할을 억제하는 것으로 보이며 배아 세포들의 투과성의 변화와는 직접 관련이 없는 것으로 사료된다.
Metabolic changes of early mouse embryos treated with progesterone were investigated in order to elucidate the mode of action of progesterone on embryogenesis in vitro. The embryos were cultured, and labelled with radioactive precursors of macromolecules for certain periods in the absence or presence of various concentrations of progesterone by employing the microtube culture technique. The changes of transport and macromolecular synthesis systems of the embryos were examined by measuring the amounts of uptake and incorporation of the precursors. The results obtained were as follows: 1. Progesterone stimulated markedly the uptake of amino acids, but rather suppressed their incorporation by embryonic cells. 2. Progesterone suppressed both the uptake and incorporation of nucleotide precursors (uridine and thymidine) by embryonic cells. 3. Progesterone penetrated into the embryonic cell membranes and was taken up by them. The present results seem to indicate that the inhibition of the progesterone on the mammalian embryogenesis in vitro may not be directly related to the membrane transport system. They seem to imply that progesterone would penetrate into the embryonic cells and may directly block the biosynethetic pathways of macromolecules, and so lead to the inhibition of the embryogenesis in vitro.
