REGULATION BY GROWTH-FACTORS OF ANGIOTENSIN-II TYPE-1 RECEPTOR AND THE A 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 bo vine adrenal fasciculata-reticularis cells (BAC). Insulin, Insulin-lik e growth factor and basic Fibroblast growth factor increased AT1 recep tors (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 pr oduction. In contrast, Transforming growth factor pi, which reduced sl ightly AT1 binding sites, but not the level of alpha q or alpha 11 pro teins, did not change the A-II-induced inositol phosphate accumulation . However, this factor, as previously reported, markedly reduced corti sol production.