RECENT DATA ON GROUP OF MELANOTROPIC AND LIPOTROPIC HORMONES (MSH-LPH) AND ON BRAIN MORPHINOMIMETRIC PEPTIDES (ENDORPHINS)

Abstract

Human .beta.-MSH was responsible for the hyper-pigmentation observed in some syndromes associated with ACTH hypersecretion. .beta.-LPH was a pituitary polypeptide, containing the entire sequence of .beta.-MSH in its fragment 37-58, and the physiological role of which remained unknown. .alpha.-MSH and CLIP (corticotropin-like intermediary peptide) were thought to be specific of certain species possessing a distinct pituitary pars intermedia. Recent data give new insight upon some of these conceptions. .beta.-MSH seems not to exist in man; it is almost established now that plasma immunoreactive .beta.-MSH (IR-.beta.-MSH) is in fact .beta.- and/or .gamma.-LPH. In chronic renal failure plasma IR-.beta.-MSH is elevated because of a decreased plasma disappearance rate, whereas ACTH is normal. Good evidence suggests that both LPH and ACTH are synthesized in the same pituitary cell within a common polypeptide precursor. Endogenous peptides with morphinomimetic activity (endorphins) have been isolated from brain and hypophysis; they are all made up of different fractions of .beta.-LPH-C-terminal fragment 61-91. It is likely that they represent a new class of brain neurotransmitters involved in some functions of the CNS, structural similarities suggest that .beta.-LPH may be the biosynthetic precursor of endorphins. However, such a hypothesis remains to be clearly demonstrated.