| Abstrakt: |
Measurements of DNA, RNA, soluble and insoluble protein, and glucose-6-phosphate dehydrogenase (G6PDH) were made in endometrium of rats ovariectomized on Day 0 (estrus) and treated daily with estrone, progesterone, or a combination of steroids. The data revealed that: (a) G6PDH responded more rapidly to both low and high dosages of estrone than did other soluble proteins; (b) progesterone alone suppressed soluble protein but maintained activity of G6PDH; (c) in the presence of low dosages of estrogen, progesterone blocked G6PDH without affecting the action of estrone on other soluble proteins; (d) with higher dosages of estrone, progesterone blocked G6PDH as effectively as other soluble proteins, but sooner; (e) the effects of the steroids on enzyme activity were not the result of alterations in the affinity of the enzyme for its substrate or cofactor; (f) estrogen-induced increases in DNA and insoluble protein were suppressed by progesterone, while RNA and soluble protein were not affected. The present results, in conjunction with other studies, provide a rationale for the role of progesterone in“progestational differentiation.” This possible“mechanism of action” of progesterone is described. |
