DEVELOPMENTAL-CHANGES IN GS AND G(OLF) PROTEINS AND ADENYLYL CYCLASESIN MOUSE-BRAIN MEMBRANES

Guanine nucleotide-binding (G) proteins, Gs and G(olf) mediate the inc rease in cAMP formation through the activation of adenylyl cyclases. T he developmental profiles of Gs, G(olf) and adenylyl cyclases were det ermined in mouse striatum and whole brain using immunobloting with spe cific antisera. Gs and the 115 kDa and 150 kDa adenylyl cyclases were present at the earliest age tested, embryonic day (E) 14.5. G(olf) and the 160 kDa adenylyl cyclase emerged in parallel, postnatally; during this period the increase in the relative abundance of the 150 kDa was observed. GppNHp activated Gs/G(olf) in a dose dependent manner, wi th a smaller response observed in embryos compared to adults. Mn2+ and forskolin activated the adenylyl cyclases and this activation increas ed during development. At E 14.5, maximal activation with Mn2+ and for skolin elicited a similar increase in cAMP levels, but from postnatal day 1, a nearly two fold higher response was obtained with forskolin c ompared to Mn2+; at the same time the 160 kDa adenylyl cyclase was det ected. These data suggest that the appearance of certain forms of stim ulatory G proteins was developmentally correlated with the expression of specific adenylyl cyclases.