INOSITOL 1,4,5-TRISPHOSPHATE RECEPTOR SUBTYPES IN ADRENAL GLOMERULOSA CELLS

Expression of the diverse subtypes of inositol 1,4,5-trisphosphate (InsP(3)) receptor (IP(3)R) was examined in rat adrenal glomerulosa cells. The polymerase chain reaction products were characterized by means of DNA sequencing and/or restriction enzyme mapping. The predominant subtype expressed is IP(3)R-1; its alternatively spliced variants containing and lacking segment SZ are present in comparable amounts, The expression 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 chronic physiological stimulus of glomerulosa cells, failed to influence the expression of IP(3)R-1, as measured by competitive polymerase chain reaction, and failed to modify the ratio of the different receptor subtypes, as studied with restriction enzyme mapping.