ONTOGENIC DEVELOPMENT OF THE ADENYLYL-CYCLASE ENZYME AND THE ALPHA(S), ALPHA(I1) AND ALPHA(I2) G-PROTEIN REGULATORY SUBUNITS FROM RAT PROSTATE

The expression of alpha(s), alpha(i1) and alpha(i2) G-protein subunits measured by immunoblot increased in the rat prostate during sexual ma turation, supporting their involvement in proliferation/differentiatio n. Northern blotting gave transcripts of 1.8 and 4 kb for alpha(s), 1. 4 and 4.5 kb (mainly) for alpha(i1), and 2.4 kb for alpha(i2) with lev els suggesting a differential regulation (at transcription or post-tra nscription for alpha(s), transcription for alpha(i1), and translation for alpha(i2)). The stimulatory effects of forskolin, vasoactive intes tinal peptide (VIP) and isoproterenol on adenylyl cyclase activity inc reased between 0.5-3 mo, remained constant up to 12 mo and decreased t hereafter, conceivably following the expression of VIP and beta-adrene rgic receptors. However, G-protein activation of adenylyl cyclase (by GTP and Gpp[NH](p)) was maximal at 0.5 mo and then decreased as it occ urred with toxin-catalyzed ADP-ribose incorporation to alpha subunits suggesting that other factors are also involved in the regulation of G -protein activity during rat prostatic development. (C) 1997 Elsevier Science Inc.