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Side-chain cleavage (SCC) of endogenous cholesterol in adrenal mitochondria isolated from ACTH-treated rats indicates that the size of the reactive cholesterol pool depends on the reducing precursor. At optimal concentrations of reductant, this pool was typically at least 2 times greater for isocitrate than for succinate. Succinate-supported reactions were(More)
Adrenal cortical mitochondria contain a mixed function oxidase capable of converting cholesterol to pregnenolone; this enzyme requires NADPH, oxygen and cholesterol. This cholesterol side chain cleavage enzyme system contains a Flavoprotein, an iron sulphur protein and a specific cytochrome P450 termed cytochrome P450scc. ACTH stimulates the adrenal cortex(More)
Transfer of cholesterol to cytochrome P450scc is generally the rate-limiting step in steroid synthesis. Depending on the steroidogenic cell, cholesterol is supplied from low or high density lipoproteins (LDL or HDL) or de novo synthesis. ACTH and gonadotropins stimulate this cholesterol transfer prior to activation of gene transcription, both through(More)
n-Hexane and cardiolipin each stimulate pregnenolone production by isolated rat adrenal mitochondria. Following corticotropin (ACTH) stimulation, mitochondrial cholesterol metabolism exhibits a fast phase lasting 2 min, followed by a 10-fold slower metabolism. ACTH suppression by dexamethazone or cycloheximide (CX) treatment removes this fast phase.(More)
The role of exogenous lipoprotein cholesterol versus endogenous cholesteryl esters as substrates in adrenal steroidogenesis was studied in isolated rat adrenal cells. Hypocholesterolemic drugs were used in rats to depress the plasma cholesterol concentration and the adrenal cholesterol concentration. Adrenal cortical cells were prepared in the usual way.(More)
The control of steroid synthesis in adrenal fasciculata cells is considered in terms of two types of control by ACTH: control of cholesterol availability to inner mitochondrial cytochrome P-450scc. This process controls total steroid synthesis and is rapidly activated by ACTH. The several steps in cholesterol transfer are examined. partitioning of(More)
Rat adrenal mitochondria exhibit a linear 2-fold accumulation of cholesterol for 20 min following either in vivo ether stress or ACTH administration, providing cholesterol metabolism is inhibited by aminoglutethimide (AMG). Additional cycloheximide (CX) pretreatment only slightly decreases this increase, but the location of accumulation shifts from the(More)
This study sought to assess the rate of hepatitis C virus (HCV) infection and associated risk factors in young adults 18–28 years of age who were incarcerated in the Rhode Island Department of Corrections. The majority of participants reported injection drug use and engaged in high-risk behaviors such as needle sharing. Despite having these risk factors and(More)
Rat adrenal mitochondria contain approximately equal levels of P450scc and P45011 beta, each reduced by NADPH through adrenodoxin reductase (ADX-reductase) and adrenodoxin (ADX). Constitutive cholesterol side-chain cleavage (SCC) can be increased over 20-fold through a combination of hormonal activation and inhibition of cholesterol metabolism in vivo prior(More)
Confluent bovine adrenal cell primary cultures respond to stimulation by adrenocorticotropin (ACTH) to produce steroids (initially predominantly cortisol and corticosterone) at about one-tenth of the output of similarly stimulated rat adrenal cells. The early events of steroidogenesis, following ACTH stimulation, have been investigated in primary cultures(More)