Ethanol induction of steroidogenesis in rat adrenal and brain is dependent upon pituitary ACTH release and de novo adrenal StAR synthesis.
The mechanisms of ethanol actions that produce its behavioral sequelae involve the synthesis of potent GABAergic neuroactive steroids, specifically the GABAergic metabolites of progesterone, (3alpha,5alpha)-3-hydroxypregnan-20-one (3alpha,5alpha-THP), and deoxycorticosterone, (3alpha,5alpha)-3,21-dihydroxypregnan-20-one. We investigated the mechanisms that underlie the effect of ethanol on adrenal steroidogenesis. We found that ethanol effects on plasma pregnenolone, progesterone, 3alpha,5alpha-THP and cortical 3alpha,5alpha-THP are highly correlated, exhibit a threshold of 1.5 g/kg, but show no dose dependence. Ethanol increases plasma adrenocorticotropic hormone (ACTH), adrenal steroidogenic acute regulatory protein (StAR), and adrenal StAR phosphorylation, but does not alter levels of other adrenal cholesterol transporters. The inhibition of ACTH release, de novo adrenal StAR synthesis or cytochrome P450 side chain cleavage activity prevents ethanol-induced increases in GABAergic steroids in plasma and brain. ACTH release and de novo StAR synthesis are independently regulated following ethanol administration and both are necessary, but not sufficient, for ethanol-induced elevation of plasma and brain neuroactive steroids. As GABAergic steroids contribute to ethanol actions and ethanol sensitivity, the mechanisms of this effect of ethanol may be important factors that contribute to the behavioral actions of ethanol and risk for alcohol abuse disorders.
Boyd
Kevin N
KN
Curriculum in Toxicology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
Kumar
Sandeep
S
O'Buckley
Todd K
TK
Porcu
Patrizia
P
Morrow
A Leslie
AL
D000311:Adrenal Glands / Q000187:drug effects*; D000324:Adrenocorticotropic Hormone / Q000097:blood*; D000818:Animals; D001921:Brain / Q000187:drug effects*; D002492:Central Nervous System Depressants / Q000494:pharmacology*; D003513:Cycloheximide / Q000494:pharmacology; D003907:Dexamethasone / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000494:pharmacology*; D018682:GABA Agents / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D005938:Glucocorticoids / Q000494:pharmacology; D007016:Hypophysectomy / Q000379:methods; D007093:Imidazoles / Q000494:pharmacology; D007074:Immunoglobulin G / Q000494:pharmacology; D047468:Immunoprecipitation; D007546:Isoquinolines / Q000494:pharmacology; D008297:Male; D008558:Melphalan / Q000494:pharmacology; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D011280:Pregnanolone / Q000378:metabolism / Q000494:pharmacology; D011284:Pregnenolone / Q000378:metabolism / Q000494:pharmacology; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D011863:Radioimmunoassay / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D018709:Statistics, Nonparametric; D013256:Steroids / Q000378:metabolism*; D000098682:Steroidogenic Acute Regulatory Protein
C120709:CB 34; D002492:Central Nervous System Depressants; D018682:GABA Agents; D005938:Glucocorticoids; D007093:Imidazoles; D007074:Immunoglobulin G; D007546:Isoquinolines; D010750:Phosphoproteins; D011500:Protein Synthesis Inhibitors; D011725:Pyridines; D013256:Steroids; C051713:antineoplastic agent K 18; D000098682:Steroidogenic Acute Regulatory Protein; D000431:Ethanol; D011284:Pregnenolone; D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone; D003513:Cycloheximide; D011280:Pregnanolone; D008558:Melphalan; C037850:PK 11195