Effects of dehydroepiandrosterone on corticosterone release in rat zona fasciculata-reticularis cells.
The decline of plasma dehydroepiandrosterone (DHEA) and maintenance of glucocorticoid levels with increasing age contribute to excess body fat accumulation, hyperglycaemia, hyperlipidaemia, hyperinsulinaemia and cancer. Although opposing actions of DHEA and corticosterone have been proposed in a rat model, the effects and action mechanisms of DHEA on rat adrenal zona fasciculata-reticularis (ZFR) cells are still unclear. This study addressed the effects of DHEA on corticosterone release, cellular cAMP production, the functions of steroidogenic enzymes and the expression levels of steroidogenic acute regulatory protein (StAR) and cytochrome P450 side-chain cleavage enzyme (P450scc). ZFR cells were incubated with DHEA in the presence or absence of adrenocorticotropin (ACTH), 8-Br-cAMP, forskolin, 25-OH-cholesterol, pregnenolone, progesterone or deoxycorticosterone at 37 degrees C for 30 min, 1 h or 5 h and the concentration of corticosterone or pregnenolone measured subsequently in the media by RIA. The cells were used to measure the content of cAMP by RIA and to extract protein for Western blot or mRNA for RT-PCR analysis. The data demonstrated that (1) DHEA inhibited ACTH-, 8-Br-cAMP-, 25-OH-cholesterol-, pregnenolone-, progesterone- or deoxycorticosterone-stimulated corticosterone release; (2) DHEA increased 25-OH-cholesterol-stimulated pregnenolone release but not when 25-OH-cholesterol was combined with trilostane; (3) DHEA increased the K(m) of 11beta-hydroxylase but not P450scc; (4) DHEA affected the expression levels of StAR protein but not of P450scc. These results suggest that DHEA acts directly on rat ZFR cells to diminish corticosterone secretion by inhibition within the post-cAMP pathway, by inhibiting steroidogenic enzymes downstream from P450scc and by inhibiting StAR expression.
Chang
Ling-Ling
LL
Department of Chemical Engineering, Chinese Culture University, Shih-Lin, Taipei 111, Taiwan, ROC. llchiang@staff.pccu.edu.tw
Wun
Wan-Song Alfred
WS
Ho
L Low-Tone
LL
Wang
Paulus S
PS
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000037:antagonists & inhibitors; D003345:Corticosterone / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000242:Cyclic AMP / Q000096:biosynthesis; D003687:Dehydroepiandrosterone / Q000494:pharmacology*; D003900:Desoxycorticosterone / Q000494:pharmacology; D013196:Dihydrotestosterone / Q000031:analogs & derivatives* / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000378:metabolism / Q000494:pharmacology; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D006888:Hydroxycholesterols / Q000494:pharmacology; D010750:Phosphoproteins; D011284:Pregnenolone / Q000378:metabolism / Q000494:pharmacology; D011374:Progesterone / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D013252:Steroid 11-beta-Hydroxylase / Q000037:antagonists & inhibitors; D015383:Zona Fasciculata / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D015385:Zona Reticularis / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D000098682:Steroidogenic Acute Regulatory Protein
D004791:Enzyme Inhibitors; D006888:Hydroxycholesterols; D010750:Phosphoproteins; D012333:RNA, Messenger; D000098682:Steroidogenic Acute Regulatory Protein; D013196:Dihydrotestosterone; D015124:8-Bromo Cyclic Adenosine Monophosphate; D003900:Desoxycorticosterone; D003687:Dehydroepiandrosterone; D011374:Progesterone; D011284:Pregnenolone; C007997:25-hydroxycholesterol; D000324:Adrenocorticotropic Hormone; D000242:Cyclic AMP; D013252:Steroid 11-beta-Hydroxylase; D002786:Cholesterol Side-Chain Cleavage Enzyme; C009954:trilostane; D015056:1-Methyl-3-isobutylxanthine; D003345:Corticosterone