Angiotensin II (Ang II) AT2 receptor-gene disrupted mice have increased systemic blood pressure and response to exogenous Angiotensin II. To clarify the mechanism of these changes, we studied adrenal AT1 receptor expression and mRNA by receptor autoradiography and in situ hybridization in female AT2 receptor-gene disrupted mice (agtr 2-/-) and wild-type controls (agtr 2+/+). We found high expression of AT1 receptor binding and mRNA in adrenal zona glomerulosa of female wild-type mice. AT2 receptors and mRNA were highly expressed in adrenal medulla of wild-type mice, but were not detected in zona glomerulosa. There was no AT2 receptor binding or mRNA in adrenal glands of AT2 receptor-gene disrupted mice. In these animals, AT1 receptor binding and mRNA were increased in adrenal zona glomerulosa and AT1 receptor mRNA was increased in the adrenal medulla when compared with wild-type animals. The present data support the hypothesis of an interaction or cross talk between AT2 and AT1 receptors in adrenal gland. The significant increase in AT1 receptor expression in the absence of AT2 receptor transcription may be partially responsible for the increased blood pressure and for the enhanced response to exogenously administered Angiotensin II in this model. Published by Elsevier Science B.V.
Research Areas and Centers
- Academic Focus: Center for Brain, Behavior and Metabolism (CBBM)