INOSITOL 1,4,5-TRISPHOSPHATE RECEPTOR SUBTYPES IN ADRENAL GLOMERULOSACELLS

Expression of the diverse subtypes of inositol 1,4,5-trisphosphate (In sP(3)) receptor (IP(3)R) was examined in rat adrenal glomerulosa cells . The polymerase chain reaction products were characterized by means o f DNA sequencing and/or restriction enzyme mapping. The predominant su btype expressed is IP(3)R-1; its alternatively spliced variants contai ning and lacking segment SZ are present in comparable amounts, The exp ression level of IP(3)R-2 is about a quarter that of IP(3)R-1, whereas IP(3)R-3 is expressed at a very low level. Sodium depletion, a chroni c physiological stimulus of glomerulosa cells, failed to influence the expression of IP(3)R-1, as measured by competitive polymerase chain r eaction, and failed to modify the ratio of the different receptor subt ypes, as studied with restriction enzyme mapping.