MEASUREMENT OF IMMUNOREACTIVE γ‐MSH IN HUMAN PLASMA

Publisher Website
Google Scholar
Abstract
A radioimmunoassay for immunoreactive γ‐MSH (IR‐γ‐MSH) in human plasma has been developed. The assay is capable of detecting normal basal circulating levels which range from < 20‐100 ng/1 at 0900 h. Plasma levels are raised concomitantly with ACTH during insulin induced hypoglycaemia and CRF stimulation and suppressed with dexamethasone. Chromatographic characterisation of IR‐γ‐MSH in plasma demonstrates a major peak of IR‐γ‐MSH, corresponding to purified glycosylated N‐terminal pro‐opiome‐lanocortin 1‐76, when IR‐γ‐MSH is secreted from the pituitary. In contrast IR‐γ‐MSH produced ectopically appears to be heterogeneous.