Ontogenic Development of the Adenylyl Cyclase Enzyme and the α s, α i1 and α i2 G-protein Regulatory Subunits from Rat Prostate

Abstract

The expression of α s, α i1 and α i2 G-protein subunits measured by immunoblot increased in the rat prostate during sexual maturation, supporting their involvement in proliferation/differentiation. Northern blotting gave transcripts of 1.8 and 4 kb for α s, 1.4 and 4.5 kb (mainly) for α i1, and 2.4 kb for α i2 with levels suggesting a differential regulation (at transcription or post-transcription for α s, transcription for α i1, and translation for α i2). The stimulatory effects of forskolin, vasoactive intestinal peptide (VIP) and isoproterenol on adenylyl cyclase activity increased between 0.5–3 mo, remained constant up to 12 mo and decreased thereafter, conceivably following the expression of VIP and β-adrenergic 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 occurred with toxin-catalyzed ADP-ribose incorporation to α subunits suggesting that other factors are also involved in the regulation of G-protein activity during rat prostatic development.