The effect of alpha-MSH on plasma growth hormone, cortisol and TSH in children.

The effect of synthetic alpha-MSH injected intravenously in a uniform dose of 3 mg was studied in 19 prepubertal children. A marked growth hormone (GH) response was seen only in 2 out of 8 constitutionally small children with a normal GH response to insulin and arginine stimulation. Three of of 11 children suffering from hypopituitarism with documented GH and other hormone deficiencies, unexpectedly, showed a significant rise of GH after alpha-MSH: all three had craniopharyngiomas. Alpha-MSH led to an increase of plasma cortisol in all except 3 patients who had secondary adrenal insuffciency. The increase of cortisol after alpha-MSH and after insulin was of the same extent: but the hypoglycemia and stress responsible for the insulin effect were not observed after alpha-MSH. It is possible that alpha-MSH acts by an ACTH-like direct stimulation on the adrenals. There was no effect of alpha-MSH on plasma TSH or on blood glucose.