Synthesis of sterols and proteins in liver biopsies from obese patients subjected to gastric or jejunoileal bypass operations.

Incorporation of 14C-acetate into digitonin-precipitable sterols and of 3H-leucine into proteins was examined in per- or post-operative liver biopsies from morbidly obese patients subjected to either gastric or jejunoileal bypass operations. Biopsies obtained from non-obese patients without liver disease served as controls. Incorporation of precursors into sterols and proteins in peroperative biopsies from obese patients (mean weight, 131 kg) did not differ from that of control subjects (mean weight, 64 kg). However, biopsies obtained from eight patients 11-53 months after jejunoileal bypass (mean weight loss, 32% of initial weight) showed an eightfold increased 14C incorporation into sterols, whereas incorporation of 3H-leucine into proteins did not differ from that of the control group. The results in postoperative biopsies (3-12 months) from 9 patients subjected to gastric bypass (mean weight loss, 25% of initial weight) did not differ significantly from those in 15 controls. The markedly stimulated biosynthesis of sterols in patients with jejunoileal bypass might reflect increased faecal excretion of cholesterol and bile acids, causing reduced feedback control mediated by bile acids and cholesterol.