Bile flow impairment of ventro-medial hypothalamus lesioned obese rats.

Cholesterol supersaturation of bile has been reported in human obesity. Since electrolytic lesions placed in the ventro-medial hypothalamus induce hyperphagia and obesity in the rat, bile flow and lipid composition have been studied two months after the induction of such stereotaxic lesions in a group of ten animals and in their sham-operated controls. Bile flow was significantly lower in obese rats than in controls. The bile flow reduction was attributed to a decrease of the bile acid independent fraction, since no variation in bile acid excretion rate and in bile to plasma ratio of [14C] erythritol was seen between the two groups. Whereas plasma cholesterol and triglycerides were higher in ventro-medial hypothalamus lesioned rats, biliary cholesterol and phospholipid excretion rates were similar in the two groups. These data indicate that stereotaxic lesions of ventro-medial hypothalamus in the rat significantly reduce bile flow, suggesting a correlation between active sodium transport at canalicular level and neuroendocrine hypothalamic function, but fail to induce qualitative alterations of bile lipid composition.