α-MSH Peptides Research Articles

Some aspects of the relationship between chemical structure and melanocyte-stimulating properties of several peptides related to adrenocorticotropin

The melanocyte-stimulating activity of several synthetic peptides whose amino acid sequences correspond to partial structures of ACTH has been determined. The duration of the response of frog melanocytes to these pepetides in vivo was studied, and two. ACTH and a synthetic nonadecapeptide, were found to have longer-lasting effects than native melanotropins. Heating with NaOH solution prolonged the melanocyte-expanding response to α-MSH and larger peptides. This treatment also incresed the potency of ACTH and of two synthetic peptides, a decapeptide and a nonadecapeptide. Evidence to suggest that the N-terminal serine may be implicated in the potentiating action of NaOH is presented.

On the presence in hog hypothalamus of 3-corticotropin releasing factor, alpha- and beta-melanocyte stimulating hormones, adrenocorticotropin, lysine-vasopressin and oxytocin.

Extracts of hog hypothalamus were chromatographed on carboxymethylcellulose. The following substances were tentatively identified in the effluents based on elution volumes and biological activities: oxytocin, β-MSH, αMSH, lysine vasopressin, β-CRF, an αMSH-like or ACTH-like peptide and ACTH.