-It has been shown that ovarian steroid hormones can reduce the incidence of cardiovascular disease in postmenopausal women. As hormone replacement therapy for postmenopausal women, progestins are added to estrogens to eliminate the increased risk of endometrial cancer. However, the effects of progestins on the atherogenic process have not been well understood. In the present study, we examined...

Controversial results obtained from human and animal studies on the prevention of heart disease by estrogens and progestins warrant a better understanding of nuclear hormone receptor function and interaction. To address this issue and taking into account that effects of synthetic progestins are not only referable to action through the progesterone receptor but may also be mediated by other ster...

In non-human primates, the oviduct undergoes dramatic, hormonally regulated changes in morphological structure. In spayed animals, the epithelium is undifferentiated, and estro­ gen treatment can stimulate differentiation to a fully ciliated and secretory state. This state can be maintained indefinitely by estrogen, but if progestin treatment is initiated the epithelium will atrophy, dedifferen...

BACKGROUND Sulfotransferases are present in normal and cancerous human breast tissues. The purpose of this article is to present a hypothetical correlation of sulfotransferase activity with proliferation in breast cancer. MATERIALS AND METHODS Sulfotransferases were evaluated in breast cancer cells by determining the transformation of non-conjugated estrogens to the sulfates. Proliferation wa...

Controlled studies and most observational studies published over the last 5 years suggest that the addition of synthetic progestins to estrogen in hormone replacement therapy (HRT), particularly in continuous-combined regimen, increases the breast cancer (BC) risk compared to estrogen alone. By contrast, a recent study suggests that the addition of natural progesterone in cyclic regimens does n...

Gonadal homogenates of rainbow trout from D(ay) 60, D100 and D200 after fertilization have been incubated in vitro in the presence of dehydroepiandrosterone-3H to demonstrate 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) and delta 5,4-isomerase activity, of pregnenolone-3H to assess the synthesis of "progestins" and of androstenedione-3H to determine oestrogen synthesis in the ovaries and th...

BACKGROUND Progestins in combination with estrogen are believed to have different effects on the cardiovascular system. The aim of this study was to investigate the influence of different oral contraceptive formulations on the development of experimental atherosclerosis and vascular reactivity. METHODS A total of 160 sexually mature rabbits were ovariectomized and randomly assigned to equally...