Autoradiographic study of hormonal regulation of proliferating golden hamster uterus cells during postnatal ontogeny

: Study of the effects of octestrol, 17-hydroxyprogesterone caproate and tamoxifen on uterine cell proliferation in golden hamsters aged one to twenty days has shown the existence in the uterine epithelium of two cell populations with varying sensitivity to sex hormones. The cells of uterine glands being formed by day 12 of postnatal ontogenesis were found to be insensitive to the proliferation-inhibiting effect of progesterone and little sensitive to the proliferation-stimulating action of the estrogen. The epithelial cells lining the uterine cavity show a high sensitivity to sex hormones. The absence of changes in proliferative activity of the epithelial cells exposed to tamoxifen allows a suggestion that ontogenetic changes in the proliferative activity of the uterine cells do not depend on the presence of endogenous hormones.