Down-regulation of vasopressin V1a receptor mRNA in diabetes mellitus in the rat.

1. To investigate the mechanism of hepatic V1a vasopressin receptor down-regulation in streptozotocin-induced diabetes mellitus in the rat, we measured hepatic V1a receptor mRNA by in situ hybridization histochemistry using oligonucleotide probes to the V1a receptor and Northern blotting. 2. Diabetes mellitus caused hyperglycaemia, hyperosmolality and increased plasma vasopressin concentrations ( P P P P 3. These findings suggest that altered V1a mRNA transcription is responsible for the reduced hepatic V1a receptor density in diabetes mellitus.