The major brain nicotinic acetylcholine receptor is assembled from two subunits termed alpha 4 and n alpha 1. When expressed in Xenopus oocytes, these subunits reconstitute a functional acetylcholine receptor that is inhibited by progesterone levels similar to those found in serum. In this report, we show that the steroid interacts with a site located on the extracellular part of the protein, t...

Norethindrone (17beta-hydroxy-19-nor-17alpha-pregn-4-en-20-yn-3-one) and norethindrone acetate (17beta-acetoxy-19-nor-17alpha-pregn-4-en-20-yn-3-one) interfered to a varying degree, by competitive inhibition, with the binding of progesterone and oestradiol to respective cytoplasmic receptors in the human uterus. Progesterone binding to 4S macromolecule was saturable and co-specific for progesti...

A recombinant full length human glucocorticoid receptor stimulates transcription in vitro of test genes containing synthetic glucocorticoid and progesterone response elements or murine mammary tumor virus promoter. The receptor expressed in a baculoviral vector is highly active, enhancing transcription of hormone response genes greater than 30-fold even at a receptor concentration of 1.2 nM. Th...

BACKGROUND The effects of progestogens on endothelial physiology are poorly studied. Prostacyclin is a potent vasodilator synthesized by two isoforms of cyclooxygenase (COX) in endothelium. We examined the effects of two clinically used progestogens, progesterone and medroxyprogesterone acetate (MPA), on prostacyclin production by cultured human umbilical vein endothelial cells (HUVEC) and the ...

The possible interaction of progesterone--receptor complexes with nucleotides was tested by affinity chromatography. The cytosol progesterone receptor from hen oviduct was partially purified by ammonium sulfate precipitation before use. When progesterone was bound to the receptor, the resulting complex could be selectively adsorbed onto columns of ATP-Sepharose. This interaction was reversible ...

We have used a new monoclonal antibody, designated C-262, directed against the last 14 amino acids of the carboxy-terminus of human progesterone receptors (N. L. Weigel et al., Mol. Endocrinol., 6: 1585-1597, 1992) to analyze progesterone receptor structure. This new antibody recognizes the previously described B-receptors (Mr 120,000) and the naturally occurring N-terminal truncated A-receptor...

Hormonal induction of sexual receptivity in ovariectomized female mice can be effectively reinstated by sequential administration of estradiol and progesterone. In this regard, mice appear to be similar to other rodents. While it is generally accepted that hypothalamic progesterone receptors function as estradiol-induced transcription factors in the induction of sexual receptivity in rats, hams...

Objective. Some effects of progesterone on glioma cells can be explained through the slow, genomic mediated response via nuclear receptors; the other effects suggest potential role of a fast, nongenomic action mediated by membrane-associated progesterone receptors. Methods. The effects of progesterone treatment on the expression levels of progesterone receptor membrane component 1 (PGRMC1), pla...

Nine human breast cancer cell lines in permanent tissue culture and currently available to researchers have been assayed for their content of cytoplasmic estrogen receptors, progesterone receptors, androgen receptors, and glucocorticoid receptors, as well as for the presence of unfilled or hormone-filled nuclear estrogen receptors. Receptor distribution varied considerably among the nine lines ...

The minimal topological difference (MTD) method is used to describe quantitative structure-activity relationships (QSAR) for the progesterone-receptor binding affinity including 59 progestational steroids. Multiple correlation coefficients of r = 0.962 and r = 0.955 are obtained by use of the MTD variable and a measure of hydrophobicity for the series of progesterone and ethisterone derivatives...