Adrenergic and cholinergic stimulation of cortisol production in primary cultures of bovine adrenocortical zona fasciculata/reticularis cells
Lightly, Eric R. T.
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In addition to the classical hormonal regulators of adrenocortical steroidogenesis, adrenocorticotrophic hormone (ACTH) and angiotensin II (ALI), there is evidence that the adrenal cortex may also be influenced by adrenergic and cholinergic control.Initial characterisation of primary cultures of bovine adrenocortical zona fasciculata / reticularis cells, prepared by a collagenase digestion procedure, showed that ACTH1_24 and All stimulated cortisol production from both freshly isolated (day 1) and cultured (day 2 - day 5) cells. Peak cortisol production was seen between days 3 and 4 for these agonists. Morphological analysis, by light and electron microscopy, of day 1 and 3 cells, showed that day 3 cells had improved integrity of ultrastructure and increased lipid deposits compared to day 1 cells.Adrenergic agonists stimulated cortisol production in a dose - depende nt manner from cultured cells, but failed to stimulate cortisol product=m from freshly isolated cells. Cholinergic agonists stimulated cortisol production in a dose -dependent manner from both freshly isolated and cultured cells. Adrenergic and cholinergic agonists also showed peak cortisol production between days 3 and 4.Using specific alpha and beta -adrenergic agonists and antagonists, it was shown that adrenergic stimulation of cortisol production from cultured cells was mediated by beta -adrenergic receptors. Schild analysis, using the specific betal- adrenergic antagonist, practolol, and the specific beta2- adrenergic antagonist, ICI118,551, identified these receptors as betai- 15 adrenoceptors. Adrenergic agonists were shown to stimulate steroidogenesis in cultured cells via a cyclic AMP dependent mechanism. These agonists had no effect on turnover of cellular phosphoinositides. Additionally, the adrenergic response of these cells exhibited homologous desensitisation.Using specific cholinergic agonists and antagonists, it was shown that M3- cholinergic receptors were responsible for mediating stimulation of cortisol production from cultured cells produced by cholinergic agonists. It was also shown that cholinergic agonists stimulated steroldogenesis in cultured cells via activation of phospholipase C, and that these agonists had no effect on cellular cyclic AMP levels.