Elevation in serum insulin, albumin, and FFA, with gains in liver lipid and protein, induced by glucocorticoid treatment in dogs

Abstract

Administration of methylprednisolone to dogs (4 mg/kg per day, intramuscularly for 17 days) had the following effects. Immunoreactive insulin (IRI) in serum (postabsorptive) rose threefold to a peak in 4 days and later returned to normal. Serum glucose was little altered. The rise in the IRI/glucose ratio suggests that the sensitivity of the insulin release mechanism of the pancreatic beta cells to glucose was increased. Serum albumin rose, concomitantly with IRI, then returned to normal at a slower rate than did IRI. Globulins were not appreciably altered. Free fatty acids (FFA) rose later, during days 7–14. Liver weight increased, owing to gains in total lipid and fat-free solids. The plasma volume percent increased, and polyuria occurred. In response to a glucose load (1 g/kg, intravenously) methylprednisolone caused an augmented rise in serum IRI on days 1 and 4, with a later return to or below normal, and an increase in the rate of disappearance and the apparent volume of distribution of glucose. Cortisone (5 mg/kg per day intramuscularly, for 6 days) exerted similar effects in the dog. The results suggest that an increased insulin secretion was induced by glucocorticoids, and that this effect was involved in enhanced synthesis of liver protein and albumin and in increased rate of uptake of glucose.