Vasopressin stimulates cortisol secretion and phosphoinositide catabolism in cultured bovine adrenal fasciculata/reticularis cells.
Cells isolated from the zona fasciculata/reticularis (ZFR) of the bovine adrenal cortex and maintained in culture were found to secrete cortisol in response to vasopressin stimulation. The increased cortisol secretion was dose dependent, with a threshold response at 1 nM and a maximal response (1.68-fold over basal) at 0.1 microM. In cells cultured in the presence of [3H]inositol (to prelabel the membrane phosphoinositide pool), stimulation with vasopressin in the presence of LiCl (10 mM) resulted in a similar dose-dependent increase in labelling of the phosphoinositol fraction, with a maximal response (1.45-fold over basal) at 10 nM. The increased labelling of the phosphoinositol fraction was independent of extracellular Ca2+ as it was not abolished in medium with [Ca2+] buffered to intracellular resting levels. This suggests that vasopressin stimulation results in the activation of a phosphoinositidase C. It is probable that cortisol secretion by bovine ZFR cells in response to vasopressin is dependent upon activation of this Ca2(+)-independent phosphoinositidase C. However, the small magnitude of the cortisol secretory response makes it unlikely that vasopressin is a primary regulator of cortisol secretion in vivo.
Bird
I M
IM
University Department of Clinical Chemistry, Royal Infirmary, Edinburgh.
Nicol
M
M
Williams
B C
BC
Walker
S W
SW
D000109:Acetylcholine / Q000494:pharmacology; D000302:Adrenal Cortex / Q000187:drug effects* / Q000378:metabolism; D000804:Angiotensin II / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology*; D002417:Cattle; D002478:Cells, Cultured; D004789:Enzyme Activation / Q000187:drug effects; D004837:Epinephrine / Q000494:pharmacology; D006854:Hydrocortisone / Q000378:metabolism*; D008563:Membrane Lipids / Q000378:metabolism*; D010716:Phosphatidylinositols / Q000378:metabolism*; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D011433:Propranolol / Q000494:pharmacology
D008563:Membrane Lipids; D010716:Phosphatidylinositols; D000804:Angiotensin II; D001127:Arginine Vasopressin; C031193:angiotensin II, Asp(1)-Val(5)-; D011433:Propranolol; D010727:Phosphoric Diester Hydrolases; C021491:glycerophosphoinositol glycerophosphodiesterase; D000109:Acetylcholine; D006854:Hydrocortisone; D004837:Epinephrine