Reduced response to phenobarbital by the liver of rats fed a choline-deficient diet

1. The response of the liver to phenobarbital administration was compared in rats fed either laboratory chow, a semipurified choline-supplemented diet or a semipurified choline-deficient diet. 2. The liver contents of proteins, lipids and cytochrome P-450, as well as the activity of aminopyrine and ethylmorphine demethylases, were measured after 5 days of feeding and five daily injections of phenobarbital. Liver sections were examined electron microscopically. 3. In rats fed the choline-supplemented diet, phenobarbital administration caused increases in cellular constituents, enzyme activities and smooth endoplasmic reticulum membranes as great as those seen in rats fed laboratory chow. However, in rats fed the choline-deficient diet, the response of the liver to phenobarbital administration was severely reduced in comparison to that in rats fed the other diets. 4. It is concluded that dietary choline and an adequate synthesis of lecithins are necessary for the induction of microsomal mixed-function oxidases and the concomitant accumulation of smooth endoplasmic reticulum in hepatocytes.

Changes in plasma insulin and glucose tolerance in stable diabetes in a young woman

In a seventeen-year-old woman with a strong family history of diabetes mellitus, changes in glucose tolerance and plasma insulin response to oral glucose were followed from the early stage of diabetes through exacerbations and remissions of the disease. At the first glucose tolerance test which revealed normal fasting and elevated postprandial blood sugar values, the plasma insulin level at thirty minutes was subnormal but the peak level, which was delayed to ninety minutes, was above normal. During the exacerbation when fasting blood sugar values were elevated, insulin response was markedly diminished. In the stage of improvement following treatment with oral drugs and insulin, plasma insulin response to oral glucose improved remarkably. During the course of subsequent exacerbation and improvement, the degree of plasma insulin response changed in a similar inverse manner with the blood sugar level. The observations suggest that the diminished insulinsecretory capacity in severe diabetes does not always indicate irreversible damage of insulin releasing mechanisms.