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 clas sified into two major distinct types, designated AT(1) and AT(2). A hi gh transient expression of AT(2) receptors in the fetal tissues has be en previously demonstrated. This study describes the cellular distribu tion of AT(2) receptor mRNA in the developing rat kidney and adrenal g land 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 detec ted 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 expr essed AT(2) receptor mRNA early during development from F12 but, unlik e the kidney, continuously expressed the mRNA at high levels through t o adulthood. The disappearance of AT(2) mRNA in the kidney was synchro nous with the completion of nephrogenesis and suggests that ANG II mig ht act through this receptor as a differentiation/growth factor during nephron development. In the adrenal gland ANG II could act as a hormo ne and also as a differentiation/growth factor via the AT(2)-receptor.