Biomaterial Database

Steroid-binding specificity of the progesterone receptor from rat placenta. 1982

T F Ogle, and B K Beyer

We have attempted to delineate some salient features of the progesterone binding site of the cytosol progesterone receptor (Rp) in rat placenta by studying the binding profile of various chemical modifications of the progesterone molecule (P). The relative competition ratio (RCR) was used to calculate the relative affinity of P and the modified ligand for receptor (Kaprog/Kainh). Cortisol exhibited no appreciable binding. Other corticoids (corticosterone, deoxycorticosterone, 11 beta-hydroxyprogesterone) had relative affinities 10-30-fold lower than P. Alterations in the structure of P which caused extensive declines in relative binding affinity (i.e. greater than or equal to 100-fold) include: reduction of A-ring to the 5 alpha-stereoisomere (A/B trans), introduction of a 17 alpha-hydroxyl group greater than removal of C17 side chain greater than reduction of C20 carbonyl. The binding profile of the rat placental Rp was similar to that described for uterine Rp from other species indicating a high degree of conservation of molecular structure for the progesterone receptor binding site from species to species.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D010920	Placenta	A highly vascularized mammalian fetal-maternal organ and major site of transport of oxygen, nutrients, and fetal waste products. It includes a fetal portion (CHORIONIC VILLI) derived from TROPHOBLASTS and a maternal portion (DECIDUA) derived from the uterine ENDOMETRIUM. The placenta produces an array of steroid, protein and peptide hormones (PLACENTAL HORMONES).	Placentoma, Normal,Placentome,Placentas,Placentomes
D011247	Pregnancy	The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.	Gestation,Pregnancies
D011980	Receptors, Progesterone	Specific proteins found in or on cells of progesterone target tissues that specifically combine with progesterone. The cytosol progesterone-receptor complex then associates with the nucleic acids to initiate protein synthesis. There are two kinds of progesterone receptors, A and B. Both are induced by estrogen and have short half-lives.	Progesterone Receptors,Progestin Receptor,Progestin Receptors,Receptor, Progesterone,Receptors, Progestin,Progesterone Receptor,Receptor, Progestin
D003600	Cytosol	Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.	Cytosols
D005260	Female		Females
D000305	Adrenal Cortex Hormones	HORMONES produced by the ADRENAL CORTEX, including both steroid and peptide hormones. The major hormones produced are HYDROCORTISONE and ALDOSTERONE.	Adrenal Cortex Hormone,Corticoid,Corticoids,Corticosteroid,Corticosteroids,Cortex Hormone, Adrenal,Hormone, Adrenal Cortex,Hormones, Adrenal Cortex
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001667	Binding, Competitive	The interaction of two or more substrates or ligands with the same binding site. The displacement of one by the other is used in quantitative and selective affinity measurements.	Competitive Binding
D013256	Steroids	A group of polycyclic compounds closely related biochemically to TERPENES. They include cholesterol, numerous hormones, precursors of certain vitamins, bile acids, alcohols (STEROLS), and certain natural drugs and poisons. Steroids have a common nucleus, a fused, reduced 17-carbon atom ring system, cyclopentanoperhydrophenanthrene. Most steroids also have two methyl groups and an aliphatic side-chain attached to the nucleus. (From Hawley's Condensed Chemical Dictionary, 11th ed)	Steroid,Catatoxic Steroids,Steroids, Catatoxic