The measurement and characterisation by high pressure liquid chromatography of immunoreactive α-melanocyte stimulating hormone in human plasma

Abstract

Abstract. Immunoreactive α-MSH was found in human plasma and in normal subjects ranged from < 10–45 pg/ml. Plasma α-MSH concentrations were within the normal range in 13 out of 15 subjects during the last trimester of normal pregnancy and only just outside the normal range in the remaining two. Elevated plasma α-MSH concentrations were found in 6 of the 11 patients with Nelson's syndrome and in 10 of the 11 patients with pituitary dependent Cushing's disease. Separation on high pressure liquid chromatography (HPLC) revealed two major peaks of immunoreactivity. These peaks, which were identified as des-acetyl α-MSH and α-MSH were similar in size in normal subjects and Cushing's disease. In Nelson's syndrome, on the other hand, there was a greater proportion of des-acetyl α-MSH and it is possible that this peptide is secreted from tumour cells of anterior lobe origin. Although there was no correlation between the circulating α-MSH and the degree of pigmentation the high concentrations of plasma immunoreactive α-MSH in Cushing's disease and the HPLC profiles in Nelson's syndrome could provide useful information as to the localization of the defects in these particular disorders.