In vitro synthesis of triglycerides and cholesterol in human gallbladder mucosa

Triglyceride and sterol synthesis was investigated in vitro in the gallbladder mucosa from control subjects and patients with acalculous cholesterolosis. The incorporation rate of 14C-acetate was 1.6 +/- 0.2 nmol/g/h into cholesterol (sum of squalene, methyl sterols, and cholesterol) and 5.7 +/- 0.8 nmol/g/h into triglycerides. The rates were significantly correlated with each other (r = 0.667). The conversion of 3H-mevalonate into cholesterol (49 +/- 10 nmol/g/h) and triglycerides (4.7 +/- 1.2 nmol/g/h) indicated a high activity in the postmevalonate cholesterol synthesis and an active shunt pathway of mevalonate metabolism. The synthesis rates of cholesterol, triglycerides, and sterol esters were closely interrelated, were unaltered in cholesterolosis, and were not correlated with the serum, biliary, and mucosal lipid concentrations. Thus, despite marked lipid accumulation the lipid synthesis proceeds effectively in the gallbladder mucosa with cholesterolosis.