Regional distribution of guanine nucleotide binding proteins (Gs and Gi alpha) in human brain: correlation with adenylyl cyclase activity.

Gs and Gi alpha immunoreactivities and adenylyl cyclase activity were measured in autopsied human brain. Highest levels of Gs 52 kDa and Gi alpha subunits occurred in frontal cortex, and highest Gs 45 kDa levels in caudate. Although basal adenylyl cyclase activity was similar in all regions, GTP gamma S-stimulated adenylyl cyclase activity and forskolin-stimulated activity showed specific brain regional patterns which correlated with Gs 45 kDa and Gi alpha levels underscoring an important functional relationship between these measures.