SUBCLASSIFICATION OF BETA-ADRENOCEPTORS RESPONSIBLE FOR STEROIDOGENESIS IN PRIMARY CULTURES OF BOVINE ADRENOCORTICAL ZONA-FASCICULATA-RETICULARIS CELLS

1. Forty eight hour primary cultures of purified bovine adrenocortical zona fasciculata/reticularis cells secreted hydrocortisone in response to stimulation with β-adrenoceptor agonists. The observed order of potency was isoprenaline > noradrenaline > dobutamine > salbutamol > BRL37344. 2. Salbutamol acted as a partial agonist on these cells hence suggesting the presence of a β1-adrenoceptor. 3. Schild analysis of the hydrocortisone response to isoprenaline showed that the selective β1-antagonist practolol and the selective β2-antagonist ICI118,551 gave pA2 values of 6.85 and 7.17, respectively. These values were in close agreement with corresponding pA2 values previously obtained for the β1-adrenoceptor. 4. We conclude that β1-adrenoceptors are responsible for mediating catecholamine-stimulated hydrocortisone secretion from primary cultures of bovine zona fasciculata/reticularis cells.