Most oral contraceptives (OC) contain a progestin in combination with an estrogen, and the progestin component in OC includes one of the following 19-nortestosterone derivatives: norethynodrel; norethindrone; or norgestrel (ievonorgestrel). It is well known that estrogens promote the growth of breast cancer. However, progestins have recently also been implicated in the development of breast can...

Accumulating evidence indicates that progestins are involved in controlling mammary gland tumorigenesis. Here, we assessed the molecular mechanisms of progestin action in breast cancer models with different phenotypes. We examined C4HD cells, an estrogen (ER) and progesterone (PR) receptor-positive murine breast cancer model in which progestins exert sustained proliferative response, the LM3 mu...

Sex steroid hormone progesterone is known to have profound effects on the growth and differentiation of the normal mammary gland and malignant breast epithelial cells. In vitro progesterone and synthetic progesterone-like compounds (progestins) inhibit breast cancer cell growth. Medroxyprogesterone acetate (MPA) is a synthetic hormone widely used in the adjuvant treatment of advanced breast can...

BACKGROUND The use of sex steroids in oral contraception or hormonal replacement therapy is associated with an increased risk of cardiovascular thromboembolic complications. Although both the estrogen and the progestin components have been involved, the underlying mechanisms responsible are unclear. METHODS AND RESULTS This study examined whether sex steroids promote hemostasis indirectly by ...

It was the aim of this study to investigate whether assessment of the metabolic stability of selected progestins of the 19-nortestosterone type in human microsomal liver preparations was a suitable approach to predict the oral bioavailability of these drugs in humans. The Michaelis-Menten parameters Vmax and KM,app for norethisterone, levonorgestrel, gestodene, desogestrel, 3-keto-desogestrel, ...

AIM To evaluate the treatment of endometrial hyperplasia (EH) with different progestins. METHODS Eighty-two women with simple EH without atypia were included. Patients were offered oral progestagens and were randomized to one of three options for 3 months: medroxyprogesterone acetate (MPA, 10 mg/day), lynestrenol (LYN, 15 mg/day) and norethisterone (NET, 15 mg/day) for 10 days per cycle. Pati...

INTRODUCTION Progesterone receptor (PR) agonists (progestins) and antagonists are developed for female contraceptives. However, non-contraceptive applications of newer progestins and PR modulators are being given more attention. AREAS COVERED The newer PR agonists including drospirenone, nomegestrol, trimegestone, dienogest and nestorone are being evaluated as contraceptives with health benef...

Progesterone (pregn-4-ene-3,20-dione; P) and its metabolite 5alpha-pregnan-3alpha-ol-20-one (3alpha,5alpha-THP) are secreted by ovaries, adrenals, and glial cells. 3alpha,5alpha-THP in the midbrain ventral tegmental area mediates sexual receptivity of rodents through its actions at GABA(A), NMDA, and/or D(1) receptors. The extent to which 3alpha,5alpha-THP may influence anti-anxiety/anti-stress...

The promoting action of E2 in breast cancer cells has been, until now, mainly linked to its action on proli®eration. Because of the importance of an increase in apoptosis in breast cancer prevention, we have studied the possible e€ects of various antiestrogens, progestins and an androgen on its occurrence in three hormone-dependent breast cancer cell lines. The antiestrogens were, a triphenylet...

Biologically important natural estrogens and progestins include estradiol, estrone, estriol, and progesterone. Estradiol-17 is the most potent estrogen that is found naturally in women. Estrone is one-tenth as biologically active as estradiol, and estriol is the weakest of the three. Estriol is synthesized by the placenta and is excreted at high levels in the urine of pregnant women. Progestero...