PORTACAVAL SHUNT AND LIPID SYNTHESIS

Abstract

A 12 y.o. girl with homozygous type II hyperlipoproteinemia has had marked improvement following portacaval (PC) shunt (Lancet, ii:944, 1973). In an attempt to explain the reduction in serum cholesterol (chol) levels, 7 dogs were given end-to-side PC anastamoses and 3 had sham operations. Fasting presurgery mean serum chol levels ± 1 SD were 193 ± 29 mg% in control and 196 ± 14 mg% in test dogs. Chol levels were statistically lower (p < .01) 1 month following surgery (controls = 205 ± 27 mg%; tests = 127 ± 21 mg%) and thereafter. The rate of chol synthesis from acetate-214C was measured in vitro on liver biopsies from the same dogs. There were no differences in the fasting rate of chol synthesis in the pre-shunt dogs or at 1 or 4 weeks after surgery. However, fed dogs at 6 weeks had a higher rate of chol synthesis for the controls (1060 ± 325 cpm/μg chol) compared to the tests (599 ± 236 cpm/μg chol). In 7 other dogs, all blood from the portal vein was supplied to the right lobes and from the IVC to the left lobes of the liver. The right lobes had a higher rate of lipid synthesis. In 8 other dogs, the pancreatic blood was supplied to the right lobes and the intestinal blood to the left lobes. The left side now showed a higher rate of lipid synthesis. These studies indicate that, at least in the dog, food or other factors absorbed from the intestine, more than pancreatic hormones, regulate the rate of hepatic chol synthesis.