Vasopressin Hormone Receptor Density and Gene Expression in Lithium Induced Polyuria Rats

Lithium, a drug frequently used for treatment of affective disorders, is known to cause a vasopressin resistant state, leading to polyuria and polydipsia. It has been suggested that lithium interacts with the renal V2-vasopressin receptor and makes the receptor dysfunctional. Detailed studies on the influence of lithium on the AVP receptor, however, have so far been difficult due to the lack of a suitable radioligand with high specific activity and high affinity. In this study, the effect of Lithium carbonate (20mg/kg i.p) on vasopressin receptor binding in the kidney and brain and the effect on mRNA expression was determined. The results of this study suggest that there was significant change in the receptor binding and gene expression in tissues of polyuria rats as compared to the control rats.