Inhibition of thyroxine-induced metamorphosis by prolactin in tadpoles, Rana catesbeiana.
Thyroxine (T4)-prolactin interactions on hepatic arginase and ornithine transcarbamylase (OTC) as well as hind legs, tail, digestive tract and median eminence were investigated in tadpoles, Rana catesbeiana. Prolactin completely blocked T4-induced tail resorption, but failed to suppress hind-leg growth, shortening of digestive tract and promotion by T4 of the median eminence development. Prolactin blocked T4-induced increase in hepatic arginase activity but not in hepatic OTC activity. A possibility that T4 and prolactin are regulating the hepatic arginase indirectly is discussed.
D000818:Animals; D001001:Anura; D001119:Arginase / Q000032:analysis; D008099:Liver / Q000201:enzymology; D008675:Metamorphosis, Biological / Q000187:drug effects*; D009954:Ornithine Carbamoyltransferase / Q000032:analysis; D011388:Prolactin / Q000494:pharmacology*; D011892:Rana catesbeiana / Q000254:growth & development*; D013974:Thyroxine / Q000037:antagonists & inhibitors*
D011388:Prolactin; D009954:Ornithine Carbamoyltransferase; D001119:Arginase; D013974:Thyroxine