EFFECT OF ORTHOTOPIC TRANSPLANTATION AND CHEMICAL DENERVATION OF THE LIVER ON HEPATIC HEMODYNAMICS IN THE RAT

The involvement of the sympathetic nervous system in the control of basal hepatic hemodynamics was investigated. Hepatic denervation was achieved by orthotopic transplantation or chemical denervation of the organ. In male Lewis rats, transplantation with rearterialization of the graft was performed. Chemical denervation was achieved by intraportal injection of 6-hydroxydopamine (75 mg/kg). Normal liver physiology was confirmed by histology and liver function tests. Four weeks post-transplantation and 7 days post-denervation, histological examination revealed no differences between transplanted, denervated and untreated or sham-operated control animals. Liver function measured by standard tests (e.g., plasma SGOT, bilirubin) was normal in all groups. The rate constants for aminopyrine breakdown in transplanted (0.015 +/- 0.005 min(-1)), denervated (0.015 +/- 0.0012 min(-1)) and control rats (0.015 +/- 0.001 min(-1)) were not significantly different. No significant difference in the rate of galactose breakdown was found. Total liver blood flow (measured by the Xe-133 clearance technique in the anesthetized animal) was unaffected by transplantation (rate constant, 0.245 +/- 0.062 min(-1); control 0.279 +/- 0.011 min(-1)). The interlobular distribution of portal blood flow was tested by intraportal injection of Cr-51-labelled microspheres. A linear relationship between flow to lobe and lobe size was confirmed in control (r = 0.95), denervated, (r = 0.99) and transplanted rats (r = 0.97) and the 'relative' flow to each lobe was not significantly different in the 3 groups. No significant differences in the 'core' to 'periphery' distribution of portal blood flow were found in the 3 groups. A small but significant portal systemic shunt was found in transplanted but not denervated or control animals. We conclude that basal hepatic hemodynamics are probably not under sympathetic control.