Role of phosphoinositol metabolism and phospholipases C and A2/A1 in signal transduction in isolated rat adrenal cells.
Isolated rat adrenal glomerulosa cells were prelabelled with [3H]inositol and stimulated with 25 nM-angiotensin II in the presence of Li+. The resulting inositol monophosphates were separated using h.p.l.c. and 2 major peaks of radioactivity were detected. These showed the same characteristics as inositol 4-phosphate and inositol 1-phosphate and stimulation with angiotensin II increased activity 4-5 fold and 7-8-fold respectively. A minor peak with the characteristics of inositol 1:2 cyclic phosphate increased 1.5-fold after stimulation. No material corresponding to inositol 2-phosphate or inositol 5-phosphate was detected. The results establish the identify of the main inositol phosphate products in angiotensin II-stimulated rat glomerulosa cells. Analysis by h.p.l.c. has been similarly used to assess the inositol phosphates produced after ACTH1-39-stimulation of isolated rat adrenal fasiculata-reticularis cells. A low dose of ACTH1-39 (10(-12) M) stimulated production of small but significant amounts of both glycerophosphoinositol and inositol monophosphate. Using superfused isolated fasiculata-reticularis cells it was also found that ACTH1-39 (10(-9) M and 10(-12) M) rapidly increased efflux of 45Ca+ from 45Ca2+-prelabelled cells. It is concluded that although the results are consistent with a role for phospholipase C in the action of angiotensin II on adrenal glomerulosa cells, in the action of ACTH on adrenal fasciculata-reticularis cells a role for phospholipase A2/A1 is implicated.
Schulster
D
D
Department of Endocrinology, National Institute for Biological Standards & Control, Potters Bar, Hertfordshire, U.K.
Smith
A D
AD
Bird
I M
IM
D000311:Adrenal Glands / Q000166:cytology; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D005260:Female; D007295:Inositol Phosphates / Q000378:metabolism*; D010740:Phospholipases / Q000502:physiology*; D010741:Phospholipases A / Q000502:physiology*; D054467:Phospholipases A2; D051381:Rats; D011919:Rats, Inbred Strains; D015398:Signal Transduction; D010738:Type C Phospholipases / Q000502:physiology*; D015384:Zona Glomerulosa / Q000187:drug effects / Q000378:metabolism*
D007295:Inositol Phosphates; D000804:Angiotensin II; D000324:Adrenocorticotropic Hormone; D010740:Phospholipases; D010741:Phospholipases A; D054467:Phospholipases A2; D010738:Type C Phospholipases