RELATIONSHIP BETWEEN GS-ALPHA MESSENGER-RIBONUCLEIC-ACID SPLICE VARIANTS AND THE MOLECULAR-FORMS OF GS-ALPHA PROTEIN IN RAT BROWN ADIPOSE-TISSUE

Recent work indicates that multiple molecular forms of Gsα can be produced by alternative splicing of a primary Gsα transcript. This study examined the pattern of expression of messenger RNAs (mRNAs) encoding the large (Gsα-L) and small (Gsα-s) molecular forms of G8a in several rat tissues, including brown adipose tissue. In all tissues examined, Gsα-L mRNA was most abundant. This was most pronounced for brain tissue (95% of total), and least for brown adipose tissue (57%). The pattern of Gsα isoform expression of a given tissue was strongly correlated with the Gsα mRNA splicing pattern in that tissue.Cold exposure and surgical denervation are treatments that have been shown to, respectively, increase or decrease total Gsα mRNA in rat brown adipose tissue. Despite producing up to 4- fold differences in total Gsα mRNA, these treatments did not affect the proportions of Gsα mRNA splice variants in brown fat. In contrast, perinatal stimulation of brown fat was associated with changes in the splicing pattern of Gsα mRNA, and these changes were reflected in Gsα protein expression. Specifically, during the perinatal period Gsα-L mRNA increased significantly but Gsα-L protein levels did not change, whereas Gsα-S mRNA did not change and Gsα-s protein levels significantly declined. These data provide further evidence that the increased Gsα mRNA levels that occur in interscapsular brown adipose tissue during periods of stimulation serve to maintain membrane levels of Gsα protein. © 1990 by The Endocrine Society.