Vasopressin mRNA in parvocellular neurons of the rat suprachiasmatic nucleus exhibits increased poly (A) tail length following water deprivation.

Dehydration is associated with altered vasopressin (VP) gene expression in the rat hypothalamus; an increase in both arginine-vasopressin mRNA abundance and size (due to 3' poly(A) tail extension) has been observed previously. We have now shown that the effects of dehydration are not restricted to the magnocellular AVP neuronal systems since VP mRNA in the suprachiasmatic nucleus (SCN) exhibits a progressive increase in poly(A) tail length during dehydration. No significant increase in VP mRNA abundance was found. Similar kinetics of poly(A) tract extension in the SCN and magnocellular supraoptic nucleus implies a common regulatory mechanism which appears to be distinct from osmotic upregulation of VP transcript abundance.