Regulation by growth factors of angiotensin II type-1 receptor and the alpha subunit of Gq and G11 in bovine adrenal cells.

In the present work we have investigated the effects of several growth factors on the expression of Angiotensin II (A-II) receptors subtype AT1 and their pertussis toxin-insensitive coupling to G-proteins in bovine adrenal fasciculata-reticularis cells (BAC). Insulin, Insulin-like growth factor and basic Fibroblast growth factor increased AT1 receptors (mRNA and binding sites) as well as the alpha subunit of Gq (mRNA and protein) and G11 (protein). These changes were associated with an enhanced A-II-induced inositol phosphate accumulation and cortisol production. In contrast, Transforming growth factor beta 1, which reduced slightly AT1 binding sites, but not the level of alpha q or alpha 11 proteins, did not change the A-II-induced inositol phosphate accumulation. However, this factor, as previously reported, markedly reduced cortisol production.