title: Induction of estrous cycles in old non-cyclic rats by progesterone, ACTH, ether stress or L-dopa.
abstract: Cycling was induced in old non-cyclic, constant estrous rats by daily injections of progesterone, ACTH or L-dopa or by subjection to ether stress. Progesterone and ACTH were the most effective agents used for re-establishing estrous cycles in these rats. Most of the progesterone- and ACTH-treated rats showed regular cycles, and their ovaries had many corpora lutea; they also showed proestrous serum LH surges. Ether stress and L-dopa mostly induced irregular cycles and fewer corpora lutea in the ovaries; a smaller  number of these rats showed proestrous LH surges. After treatment with each of these agents was discontinued, most of the rats returned to constant estrus or irregular cycling.
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000494:pharmacology*; D000367:Age Factors; D000818:Animals; D004971:Estrus / Q000187:drug effects*; D004986:Ether / Q000494:pharmacology*; D005019:Ethyl Ethers / Q000494:pharmacology*; D005260:Female; D007980:Levodopa / Q000494:pharmacology*; D007986:Luteinizing Hormone / Q000097:blood; D011247:Pregnancy; D011374:Progesterone / Q000494:pharmacology*; D051381:Rats
chemical_list: D005019:Ethyl Ethers; D004986:Ether; D007980:Levodopa; D011374:Progesterone; D000324:Adrenocorticotropic Hormone; D007986:Luteinizing Hormone