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Oxygen-dependence of ACTH-stimulated aldosterone and corticosterone synthesis in the rat adrenal cortex: developmental aspects. J Endocrinol 2002 Mar;172(3):595-604

Date

03/05/2002

Pubmed ID

11874708

DOI

10.1677/joe.0.1720595

Scopus ID

2-s2.0-0036125995   20 Citations

Abstract

The control of ACTH-stimulated steroidogenesis under decreasing levels of O(2) is not fully understood. The purpose of this study was to examine the effects of decreased O(2) in vitro on rat adrenocortical steroid synthesis at different stages of development. Of interest was the evaluation of the effect of low O(2) on steroidogenesis during the stress hyporesponsive period of the neonate. Rats were killed at 7, 14, or 42 days of age, adrenals collected and capsules (zona glomerulosa, ZG) separated from subcapsules (zona fasciculata/reticularis, ZFR). Cells were dispersed and placed into glass vials each gassed with a different level of O(2) (21, 5, 2, 1, or 0% O(2)). The entire steroidogenic pathway was analyzed by measuring ACTH-stimulated cAMP, corticosterone and aldosterone production during a 2 h incubation. In addition, the early (P450 scc) and late (P450c11 beta and P450 aldo) pathway activities were examined in the presence of cyanoketone. The PO(2) for half-maximal activity (P(50)) for aldosterone synthesis in ZG cells from 7- and 42-day-old rats was approximately 28 mmHg and 7 mmHg respectively, indicating that cells from older rats were more resistant to inhibition by low O(2). The P(50) for cAMP production from the ZG was approximately 14 mmHg for both age groups. The P(50) for corticosterone synthesis was approximately 28 mmHg and <7 mmHg in ZFR cells from 7- and 42-day-old cells respectively. The only enzyme activities affected by low O(2) (<35 mmHg) were P450 aldo and P450 scc. Moderate decreases in O(2) (from approximately 150 mmHg) decreased aldosteronogenesis, possibly due to observed decreases in cAMP generation, but not due to decreases in steroidogenic enzyme activity (7-day-old). Severe decreases in O(2) presumably inhibited P450 aldo through a direct effect on enzyme activity (both ages). P450 scc activity (including cholesterol transport) also seems to be decreased by very low O(2) (7-day-old). These findings illustrate a novel developmental alteration in O(2)-regulated steroid production, and may have implications for neonatal health and disease.

Author List

Bruder ED, Nagler AK, Raff H

Author

Hershel Raff PhD Professor in the Medicine department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Adrenal Cortex Hormones
Adrenocorticotropic Hormone
Aldosterone
Animals
Animals, Newborn
Bucladesine
Cells, Cultured
Cholesterol
Cholesterol Side-Chain Cleavage Enzyme
Corticosterone
Cytochrome P-450 Enzyme System
Hypoxia
Pregnenolone
Rats
Rats, Sprague-Dawley
Steroid 11-beta-Hydroxylase
Stimulation, Chemical
Zona Glomerulosa
jenkins-FCD Prod-484 8aa07fc50b7f6d102f3dda2f4c7056ff84294d1d