The <i>in vitro</i> enzymic hydroxylation of steroid hormones. 1. Factors influencing the enzymic 11β-hydroxylation of 11-deoxycorticosterone

Brownie, Alexander C.; Grant, J. K.

doi:10.1042/bj0570255

Cited by 82 publications

(37 citation statements)

References 25 publications

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“…The high adenyl cyclase activity of adrenal cortex mitochondria as found by Hechter et al [3] is apriori compatible with the reported stimulation, by cyclic AMP, of the 1 l/3-hydroxylation in adrenal cortex [8] and with the mitochondrial localization of 1 lo-hydroxylase [9]. However, since the purity of the mitochondrial preparations obtained by these authors was assessed only by electron microscopy and not on enzymatic criteria, we decided to undertake a more detailed investigation on the subcellular distribution of adenyl cyclase in adrenal cortex.…”

Section: Introductionsupporting

confidence: 84%

Intracellular localization of adenyl cyclase and of binding sites for 3′, 5′‐adenosine monophosphate in adrenal cortex

Satre¹,

Chambaz²,

Vignais³

et al. 1971

FEBS Letters

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Section: Introductionsupporting

confidence: 84%

Intracellular localization of adenyl cyclase and of binding sites for 3′, 5′‐adenosine monophosphate in adrenal cortex

Satre¹,

Chambaz²,

Vignais³

et al. 1971

FEBS Letters

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“…The situation has been assumed by most workers to be identical with that pertaining in adrenal-cortex mitochondria where the ability of tricarboxylic acid cycle intermediates to support steroid hydroxylation has been observed by several groups of investigators [7-91. It has been demonstrated that respiration and oxidative phosphorylation are inhibited by deoxycorticosterone hydroxylation when they share a common electron donor and Cammer and Estrabrook, and Sauer [lo, 111 suggested that tricarboxylic-acidcycle intermediates supported 11B-hydroxylation by reducing NADP+ intramitochondrially via a trans-mycin or cyanide [8,[12][13][14], suggested that transfer of reducing power for steroid hydroxylation was dependent upon oxidative phosphorylation. Estabrook and coworkers [lo] proposed that in the adrenal cortex the two mitochondria1 electron-transfer chains were connected via an energy-dependent transhydrogenase.…”

mentioning

confidence: 99%

Electron Flow and Cholesterol‐Side‐Chain Cleavage in Ovarian Mitochondria

Robinson¹,

Stevenson²

1971

European Journal of Biochemistry

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The supply of electrons for the hydroxylation reactions associated with cholesterol side-chain cleavage has been studied in intact porcine luteal mitochondria. The work was based on an assay of the NADPH-dependent side-chain-cleavage reaction, the activity of the mitochondria1 enzyme complex being expressed as the percentage of [4-14C]cholesterol converted to the products, [4-14C]pregnenolone and [4-14C]progesterone, in 1 h. The reaction could best be supported by intermediates of the tricarboxylic acid cycle, although NADPH, and to a lesser degree NADH, would also support some activity.Investigations of the ADP:O ratios of the substrates which could support cholesterol side-chain cleavage showed that they were lower than the ADP:O ratios found for the same substrates in liver mitochondria from the same animal; respiratory-control ratios were also lower in the ovarian preparation. In the adrenal cortex, another steroid-hydroxylating tissue, similar results obtained by other workers have been interpreted as indicating that the two oxidative chains, the first terminating in cytochrome oxidase and the second in cytochrome P450, are connected by an energy-dependent transhydrogenase. In the ovary this explanation may be true for succinate, but it does not satisfy the results obtained with substrates which reduce NAD(P)+. Although spectrophotometric assays showed that there was some energy-linked transhydrogenase, as well as non-energy-linked transhydrogenase activity in ovarian mitochondria, all the evidence obtained by investigating cholesterol side-chain cleavage supported by NADH and the NAD+-specific 2-oxoglutarate dehydrogenase indicated that in ovary hydrogen transfer from NADH to the cholesterol-hydroxylation site was not dependent on energy. I n contrast, inhibitors of NADH oxidase markedly stimulated NADH-supported side-chain cleavage. Energy was required for the transfer of electrons from succinate to the site of cholesterol side-chain cleavage.Mitochondria from ovarian tissue possess in addition to the normal respiratory cytochrome system [i] a second electron-transport chain concerned with steroid-hydroxylation reactions [l-31 and in particular, with cholesterol side-chain cleavage. This latter electron-transport chain, like that associated with steroid hydroxylation in adrenal-cortex mitochondria [4,5] Trivial Names. Cholesterol, 5-cholesten-3/?-01; deoxycorticosterone, 21-hydroxy-4-pregnene-3,20-dione; pregnenolone, 3/?-hydroxypregn-5-en-20-one ; progesterone, 4-pregnene-3,2O-dione.

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“…This would appear reasonable if the endoplasmic reticulum can be considered an intracytoplasmic extension of the extracellular space which acts as a conduit from cell to exterior (Carr, 1960) but in this respect the distinction between the endoplasmic reticulum and the Golgiform apparatus is apt to be confusing both morphologically and terminologically. In the light of the ultrastructural evidence it seems no mere coincidence that biochemical studies have shown the two enzymes involved in the last stages of corticosteroidogenesis to be associated with the mitochondria and the endoplasmic reticulum respectively (Brownie & Grant, 1954;Grant, 1962;Plager & Samuels, 1954). Thus corticosteroid might gain the cell exterior via the endoplasmic reticulum which here may exist as a tubular system opening to the extracellular or subendothelial space; the possibility that exocytosis or reverse pinocytosis participates to some extent in this scheme must obviously also be considered.…”

Section: E K Matthews and M Saffranmentioning

confidence: 99%

Steroid production and membrane potential measurement in cells of the adrenal cortex

Matthews¹,

Saffran²

1967

The Journal of Physiology

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3. The log dose-response relation between the concentration of ACTH in the incubation medium and the amount of corticosteroid produced by the adrenal tissue was linear.4. No evidence was found of a direct relation between the production of corticosteroid by adrenocortical cells and the cellular membrane potential. Indeed, the output of steroid appeared to be relatively independent of the polarization of the cell membrane.

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The in vitro enzymic hydroxylation of steroid hormones. 1. Factors influencing the enzymic 11β-hydroxylation of 11-deoxycorticosterone

Cited by 82 publications

References 25 publications

Intracellular localization of adenyl cyclase and of binding sites for 3′, 5′‐adenosine monophosphate in adrenal cortex

Intracellular localization of adenyl cyclase and of binding sites for 3′, 5′‐adenosine monophosphate in adrenal cortex

Electron Flow and Cholesterol‐Side‐Chain Cleavage in Ovarian Mitochondria

Steroid production and membrane potential measurement in cells of the adrenal cortex

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