EFFECT OF α-MSH ON PLASMA GROWTH HORMONE (GH), TSH AND CORTISOL IN CHILDREN

Abstract

The effect of α-MSH was studied in 19 prepubertal children (mean age 6.85 yrs) with small stature. The tests have been performed in order to rule out GH deficiency. α-MSH was injected intravenously (3 mg during 1–2 min.). Blood samples were taken at 0, 15, 30, 45 and 60 min. In addition, all children had arginine and insulin tolerance tests. GH and TSH were determined by RIA, cortisol by protein binding assay. Results : α-MSH was well tolerated, no untoward or stress reactions could be observed. A normal GH response to α-MSH was seen only in 2 out of 8 children with constitutional small stature and otherwise normal GH secretion. 3 of 11 children suffering from hypopituitarism with documented GH and other hormonal deficiencies, unexpectedly, showed a small but significant rise of GH after α-MSH; all 3 had craniopharyngeoma. α-MSH led to a clear cut increase of cortisol in all but 3 patients with secondary adrenal insufficiency requiring steroid replacement therapy. In each single child, the rise of cortisol after α-MSH and after insulin was of equal size suggesting a common mechanism of action. However, hypoglycemia and stress, as seen in the insulin tolerance test, has not been observed after α-MSH. There was no effect of α-MSH on plasma TSH.