Vasopressin stimulates dna synthesis in cultured rat hepatocytes

Liver regeneration following partial hepatectomy is significantly impaired in rats with hereditary vasopressin (AVP) deficiency. This suggested that AVP might have a direct effect on cultured rat hepatocytes. Hepatocytes from male Sprague-Dawley rats were isolated using a two-step collaganase perfusion technique and plated at a density of 10⁵/16-mm Primaria plate. After a suitable attachment period, hepatocytes were incubated with minimal essential media, AVP, AVP plus a specific AVP antagonist, or oxytocin. Hepatocyte proliferation was measured by [³H]thymidine incorporation ([³H]Thy) into hepatocyte DNA. AVP (10 nM) increased [³H]Thy significantly (and this effect was blocked by an AVP-specific antagonist (50 nM). Oxytocin had no effect on hepatocyte DNA synthesis. To further investigate the influence of AVP on hepatocyte proliferation, the effect of AVP on transforming growth factor-α (TGF-α)-stimulated hepatocyte proliferation was also studied. This combination was chosen based on the ability of AVP to inhibit the biologic effects of EGF (a TGF-α analog). There was significant attenuation of TGF-α (50 nM)-stimulated [³H]Thy in the presence of AVP (10 nM). In summary: (l) AVP stimulates proliferation of cultured rat hepatocytes. (2) The effect of AVP can be significantly abolished by a specific AVP antagonist. (3) The proliferative response of AVP is specific. (4) AVP significantly attenuates TGF-α-stimulated hepatocyte hepatic DNA synthesis. Further studies should elucidate the mechanisms for the effects of AVP on hepatic proliferation alone or in combination with other factors.