title: Inhibition of cyclic 3',5' monophosphate synthesis in rat testis by L-triiodothyronine.
abstract: Cytosolic adenylate cyclase activity from rat seminiferous tubules is inhibited by L-triiodothyronine (L-T3). In a typical dose-response curve, using Mn-ATP as substrate, no effect is observed at 10(-10) M L-T3; about 15 to 25% inhibition is found in the range between 10(-9) and 10(-6) M L-T3 and finally a sharp enzyme inhibition is evident at increasing hormone concentrations from 10(-6) to 10(-4) M. Incubation of decapsulated testes with L-T3 leads to a decrease of intracellular cyclic AMP levels. Dose-response relationships for such effect are similar to those found for adenylate cyclase activity. In this case a clear response is observed at 10(-8) M L-T3.
mesh_terms: D000067956:Adenylyl Cyclase Inhibitors; D000818:Animals; D000242:Cyclic AMP / Q000096:biosynthesis*; D003600:Cytosol / Q000201:enzymology; D004305:Dose-Response Relationship, Drug; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D008297:Male; D008345:Manganese / Q000378:metabolism; D051381:Rats; D013347:Subcellular Fractions / Q000201:enzymology; D013737:Testis / Q000201:enzymology / Q000378:metabolism*; D014284:Triiodothyronine / Q000494:pharmacology*
chemical_list: D000067956:Adenylyl Cyclase Inhibitors; D014284:Triiodothyronine; D008345:Manganese; D000242:Cyclic AMP; D008274:Magnesium