A Comparison of the β-Melanocyte-Stimulating Hormone and Corticotropin Response to Hypoglycemia

Abstract

Immunoreactive human β-melanocyte-stimulating hormone (β-MSH) has been measured in extracted plasma using a rabbit antiporcine β-MSH antiserum. An excellent correlation (r = 0.95) was observed between the logarithm of the plasma concentration of immunoreactive plasma corticotropin (ACTH) and β-MSH in 21 patients with chronically elevated ACTH levels due to either adrenal insufficiency or Cushing's Disease. This relationship between plasma ACTH and β-MSH levels was obtained irrespective of whether the patients were receiving adrenal glucocorticoids. However a group of 15 patients with a normal ACTH response to insulin induced hypoglycemia failed to show a comparable increase in plasma β-MSH during this test. It is concluded that there is a good correlation between plasma ACTH and β-MSH in conditions associated with chronic abnormalities of the glucocorticoid feedback system. However, with the radioimmunoassay methods employed no such correlation could be observed during the acute period of ACTH release which follows insulininduced hypoglycemia.