title: Ability of human chorionic gonadotropin beta-subunit to inhibit the steroidogenic response to lutropin.
abstract: Ability of the beta-subunit of human chorionic gonadotropin to inhibit the response to lutropin (luteinizing hormone, LH) was tested in the immature rat ovarian system and pregnant-mare-serum-gonadotropin-primed rat ovarian system with progesterone production being used as the response. Human chorionic gonadotropin beta-subunit was found to inhibit human and ovine lutropin-stimulated progesterone production. At a constant dose of lutropin, inhibition was dependent on the concentration of beta-subunit. When concentration of the beta-subunit was kept constant at 5.0 microgram/ml and the concentration of lutropin was varied, the inhibition was maximum at the saturating concentration of the native hormone. The alpha-subunit of the human chorionic gonadotropin did not inhibit the response to lutropin. The lutropin/beta-subunit ratio required to produce an inhibition of response was much lower than that required to bring about an observable inhibition of binding.
mesh_terms: D000818:Animals; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D003864:Depression, Chemical; D004305:Dose-Response Relationship, Drug; D005260:Female; D007986:Luteinizing Hormone / Q000494:pharmacology*; D010053:Ovary / Q000187:drug effects / Q000378:metabolism; D011374:Progesterone / Q000096:biosynthesis*; D051381:Rats
chemical_list: D006063:Chorionic Gonadotropin; D011374:Progesterone; D007986:Luteinizing Hormone