The influence of thyroid function on the diabetogenic action of triamcinolone in man. Glucose, insulin and growth hormone patterns after on oral glucose load

In vitro evidence that hypothyroidism modifies glucocorticoid receptors

We have previously reported that hypothyroidism is accompanied by modifications of the cytosolic rat liver glucocorticoid receptors. In the present study we have used molybdate, which stabilizes the glucocorticoid receptor from hypothyroid rats, allowing its characterization. We confirm a decrease in the number of glucocorticoid binding sites in the liver of hypothyroid rats as compared to that in normal rats (8000 per cell versus 23,000 per cell for normal rats). At 22 degrees C and in the absence of molybdate, thermal activation shows the same kinetics in both complexes from normal and hypothyroid rats, though activated hormone-receptor complexes from hypothyroid rats are progressively degraded (t 1/2 = 230 min). At the same temperature the dissociation rate of native complexes from hypothyroid rats is slower (k-1 = 8 X 10(-3) min-1) than normal (k-1 = 16 X 10(-3) min-1). Competitive dissociation studies using [3H]dexamethasone indicate that native complexes from hypothyroid rats show altered affinities for agonist and antagonist. Hypothyroidism decreases the number of rat liver glucocorticoid receptors and alters their properties, as evidenced by their greater instability and differences in steroid binding. These effects may be due to regulating factors and/or slight, probably post-transcriptional, modifications of the binding protein.

Erythrocytes within pancreatic B-cells of corticosteroid-treated mice

An ultrastructural study of the endocrine pancreas of female ICR mice that received 21 daily injections of the synthetic glucocorticoid, Triamcinolone diacetate (8 mg/kg b.wt) revealed some examples of microhaemorrhage within islets of Langerhans, extravasation of erythrocytes, and the presence of erythrocytes within B-cells, where they undergo degradation to form myelin-like configurations.