EXPRESSION OF ANGIOTENSIN-II AT(2) RECEPTOR MESSENGER-RNA DURING DEVELOPMENT OF RAT-KIDNEY AND ADRENAL-GLAND

The angiotensin II (ANG II) receptors have been pharmacologically classified into two major distinct types, designated AT(1) and AT(2). A high transient expression of AT(2) receptors in the fetal tissues has been previously demonstrated. This study describes the cellular distribution of AT(2) receptor mRNA in the developing rat kidney and adrenal gland by in situ hybridization with S-3S-labeled cRNA probes. From day 12 of fetal life (F12) to day 15 postpartum (D15) AT(2) mRNA was detected in the undifferentiated nephrogenic mesenchymal tissue but not in the immature and mature glomeruli and tubules of the kidney. No AT(2) mRNA was observed in the kidney after D22. The adrenal gland also expressed AT(2) receptor mRNA early during development from F12 but, unlike the kidney, continuously expressed the mRNA at high levels through to adulthood. The disappearance of AT(2) mRNA in the kidney was synchronous with the completion of nephrogenesis and suggests that ANG II might act through this receptor as a differentiation/growth factor during nephron development. In the adrenal gland ANG II could act as a hormone and also as a differentiation/growth factor via the AT(2)-receptor.