title: LH responses to LHRH, DBcAMP, and 17 beta-estradiol in cultures derived from aged rats.
abstract: Effects of luteinizing hormone-releasing hormone (LHRH), N6,O2'-dibutyryl adenosine 3',5'-cyclic monophosphate (DBcAmP), and 17 beta-estradiol (E2) on LH responses were compared in 4-day-old pituitary cultures derived from female rats (Fischer 344) of 9 and 31 mo of age. Pituitary LH contents were similar in 5 X 10(5) freshly dispersed cells prepared from the two groups of rats. LH release in response to a 4-h incubation with 10 nM LHRH was virtually the same in cultures derived from 9- and 31-mo-old rats, 140 +/- 2 ng and 138 +/- 18 ng/4 h, respectively. In cultures derived from 9-mo-old rats, incubation with 8 mM DBcAMP for 4 h significantly stimulated LH release (286% of control level), and treatment with 10 nM E2 for 3 days significantly increased both basal LH release and LH accumulation (sum of LH contents in cells and medium) to 162 and 125% of control level, respectively. Neither DBcAMP nor E2 affected cultures derived from the 31-mo-old rats. These results indicate that there is a difference in the LH response to DBcAMP and E2 between cultures derived from 9- and 31-mo-old rats. The loss of pituitary responsiveness to DBcAMP and E2 and the loss of pituitary cyclicity in the aged female rat may be causally related.
mesh_terms: D000375:Aging; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology*; D046508:Culture Techniques; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D007986:Luteinizing Hormone / Q000378:metabolism*; D010902:Pituitary Gland / Q000187:drug effects / Q000378:metabolism*; D011863:Radioimmunoassay; D011869:Radioligand Assay; D051381:Rats; D011916:Rats, Inbred F344
chemical_list: D007987:Gonadotropin-Releasing Hormone; D004958:Estradiol; D003994:Bucladesine; D007986:Luteinizing Hormone