Plasma cholesterol levels in eviscerated rats.

Eviscerated rat models with a functional liver in which the kidneys or pancreas could be left in situ or removed were used. We found that removal of the gastrointestinal tract leaving the liver and kidneys intact resulted in a significant elevation above normal of the plasma cholesterol. In the absence of the liver, esterified cholesterol is decreased. The presence or absence of the kidneys plays no role here; esterification of cholesterol is primarily a liver function. The elevation in total cholesterol levels after removal of the gastrointestinal tract and pancreas is probably due to a lack of insulin action on peripheral tissues. This elevation in cholesterol is similar to that seen in genetic, surgical and chemical diabetes. Complete restoration of plasma cholesterol patterns to intact animal levels was seen only when the pancreas, liver and kidneys were left functional in the eviscerated rat. These data indicate that in this experimental model the absence of the intestinal tract per se does not significantly modify plasma cholesterol levels and that the critical regulators of cholesterol metabolism appear to be the liver and the endocrine pancreas.

Plasma cholesterol levels in eviscerated rats.

Eviscerated rat models with a functional liver in which the kidneys or pancreas could be left in situ or removed were used. We found that removal of the gastrointestinal tract leaving the liver and kidneys intact resulted in a significant elevation above normal of the plasma cholesterol. In the absence of the liver, esterified cholesterol is decreased. The presence or absence of the kidneys plays no role here; esterification of cholesterol is primarily a liver function. The elevation in total cholesterol levels after removal of the gastrointestinal tract and pancreas is probably due to a lack of insulin action on peripheral tissues. This elevation in cholesterol is similar to that seen in genetic, surgical and chemical diabetes. Complete restoration of plasma cholesterol patterns to intact animal levels was seen only when the pancreas, liver and kidneys were left functional in the eviscerated rat. These data indicate that in this experimental model the absence of the intestinal tract per se does not significantly modify plasma cholesterol levels and that the critical regulators of cholesterol metabolism appear to be the liver and the endocrine pancreas.

Effect of corticosteroids on arachidonate induced mortality in male and female mice.

Sodium arachidonate (50 mg/kg) given intravenously to male and female mice induces pulmonary emboli followed by respiratory distress and cyanosis. Female mice are significantly more resistant to this treatment than male mice. Cortisone pretreatment for four days to intact mice (10 mg/kg/day/4 days) had a significant protective effect in both males and females against arachidonate toxicity, eliminating the sex difference previously observed. Adrenalectomy four days before arachidonate infusion increased the sensitivity to SA and resulted in 100% mortality in both sexes. Pretreatment of adrenalized animals with cortisone significantly reduced to some degree the mortality rate in both sexes. Castration of male and female mice three weeks before adrenalectomy did not affect the mortality rate seen following adrenalectomy alone. In conclusion, exogenous cortical steroids augment the resistance of even intact mice and are absolutely necessary for survival in adrenalectomized animals. The observed sex differences in untreated intact animals is not seen after treatment with cortisone or adrenalectomy.