Involvement of cAMP but not PKA in the increase of corticosterone secretion in rat zona fasciculata-reticularis cells by aging.
The effects and mechanisms of aging on corticosterone secretion in zona fasciculata-reticularis (ZFR) cells of ovariectomized (Ovx) rats were studied. Young (3-month) and old (24-month) female rats were Ovx for 4 days before decapitation. ZFR cells were isolated and incubated with different hormones or reagents at 37 degrees C for 30 min. Aging increased the basal secretion of corticosterone both in vivo and in vitro. The adrenocorticotropin (ACTH)-, forskolin-, 3-isobutyl-l-methylxanthine (IBMX)-, 8-bromo-adenosine 3',5'-cyclic monophosphate (8-Br-cAMP)-, and ovine prolactin (oPRL)-stimulated release of corticosterone by ZFR cells was greater in old than in young Ovx rats. H89, an inhibitor of protein kinase A (PKA), decreased the production of corticosterone in ZFR cells from young but not old Ovx rats. Forskolin-, or IBMX-induced production of cAMP was greater in old than in young Ovx animals, which correlated with the increase of corticosterone production by aging. The activity of 11 beta-hydroxylase that converts deoxycorticosterone (DOC, 10(-9) or 10(-8) M) to corticosterone in rat ZFR cells was decreased by age. However, the corticosterone production in response to high dose of DOC (10(-7) M) was indifferent between young and old groups. These results suggest that aging increases corticosterone production in Ovx rats via a mechanism in part associated with an increase of adenylyl cyclase activity and a decrease of phosphodiesterase activity, and then an increase of the generation of cAMP, but not related to either PKA activity or 11 beta-hydroxylase.
Lo
Ming-Jae
MJ
Department of Physical Therapy, Hung Kuang Institute of Technology (MJL), Taichung, Taiwan, Republic of China. lo@sunrise.hkc.edu.tw
Wang
Paulus S
PS
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000262:Adenylyl Cyclases / Q000378:metabolism; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000375:Aging / Q000378:metabolism*; D000818:Animals; D002352:Carrier Proteins / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D003345:Corticosterone / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D003900:Desoxycorticosterone / Q000494:pharmacology; D005260:Female; D047908:Intracellular Signaling Peptides and Proteins; D007546:Isoquinolines / Q000494:pharmacology; D010052:Ovariectomy; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D011388:Prolactin / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013449:Sulfonamides; D015383:Zona Fasciculata / Q000187:drug effects / Q000378:metabolism*; D015385:Zona Reticularis / Q000187:drug effects / Q000378:metabolism*
D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D007546:Isoquinolines; D010726:Phosphodiesterase Inhibitors; D013449:Sulfonamides; C015482:protein kinase modulator; D005576:Colforsin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D003900:Desoxycorticosterone; D000324:Adrenocorticotropic Hormone; D011388:Prolactin; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D010727:Phosphoric Diester Hydrolases; D000262:Adenylyl Cyclases; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide; D015056:1-Methyl-3-isobutylxanthine; D003345:Corticosterone