title: Inhibition of cortisol production in isolated guinea-pig adrenal cells.
abstract: Cortisol, added to 1 ml incubation medium containing 3-4 X 10(5) isolated guinea-pig adrenal cells, provoked a decrease in basal and ACTH (250 pg)-stimulated cortisol production, in correlation with the amounts used (50 ng-2,000 ng). A decrease in aldosterone production could be seen when cortisol concentrations reached or exceeded 1,000 ng/ml. There were no variations in either androgens (delta 4-androstenedione, dehydropiandrosterone) or 17-hydroxyprogesterone. Only 11-deoxycortisol was slightly increased. Using increasing concentrations of ACTH (50-250 pg), both in the absence and in the presence of 1,000 ng cortisol, it was noted that the inhibition induced by cortisol was of a competitive type and could be overcome by ACTH. This decrease in cortisol was concomitant with an increase in 11-deoxycortisol. Neither corticosterone nor dexamethasone reduced cortisol production. In addition, it was shown that the conversion of tritiated 11-deoxycortisol to radioactive cortisol increased significantly under the influence of 250 pg ACTH (mean relative variation of 21.7% +/- 7.7 (SEM), n = 6, P less than 0.05); but decreased significantly under the combined effect of 1,000 ng exogenous cortisol and the same dose of ACTH: (mean relative variation of 4.3% +/- 1 (SEM), n = 8, P less than 0.005). There is therefore reason to believe that the concentrations of cortisol at the adrenal level modulate the stimulation induced by ACTH and that this self-adjustment forms part of the control mechanisms involved in corticosteroidogenesis.
mesh_terms: D000311:Adrenal Glands / Q000166:cytology / Q000378:metabolism*; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000450:Aldosterone / Q000096:biosynthesis; D000728:Androgens / Q000096:biosynthesis; D000818:Animals; D002478:Cells, Cultured; D003345:Corticosterone / Q000494:pharmacology; D003350:Cortodoxone / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology; D006168:Guinea Pigs; D006854:Hydrocortisone / Q000096:biosynthesis* / Q000494:pharmacology
chemical_list: D000728:Androgens; D000450:Aldosterone; D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone; D003345:Corticosterone; D003350:Cortodoxone; D006854:Hydrocortisone