Expression of arginine vasopressin and vasopressin V1a receptor mRNA in diabetic (db/db) mice.

To assess the involvement of arginine vasopressin (AVP) in genetical diabetic (db/db) mice, we examined the mRNA expression levels of AVP and vasopressin V(1a) receptors (V(1a)R) in brain and liver of db/db mice. In 10 week-old db/db mice, a significant elevation in blood sugar levels and plasma osmolality were observed, showing obvious diabetic symptoms. There was a significant increase in brain AVP mRNA levels in db/db mice. The expression level of liver V(1a)R mRNA in db/db mice was significantly down-regulated, presumably as a consequence of ligand-receptor interaction. This is in contrast to results that show no significant reduction in brain V(1a)R mRNA levels when comparing db/db and control mice. Thus, it is possible that in the progress of genetic diabetes mellitus, AVP acts in liver than in brain through V(1a)R.