Melanostatin is an endogenous peptide.1,2 It is formed from pro-neuropeptide Y when pro-neuropeptide Y is cleaved into melanostatin and C-flanking peptide of neuropeptide Y (NPY).2 Melanostatin inhibits α-melanocyte-stimulating hormone (α-MSH) release from primary frog neurointermediate lobes (NILs; ED50 = 100 nM).1 It inhibits thyrotropin-releasing hormone-induced increases in intracellular calcium in primary frog melanotrope cells when used at a concentration of 100 nM. Intracerebroventricular administration of melanostatin (5 or 10 nmol/kg) increases food intake in frog larvae.3 It increases mean blood pressure in normotensive sharks when administered at a dose of 5 nmol/kg.4
References:
[1]. Galas, L., Tonon, M.C., Beaujean, D., et al.Neuropeptide Y inhibits spontaneous α-melanocyte-stimulating hormone (α-MSH) release via a Y5 receptor and suppresses thyrotropin-releasing hormone-induced α-MSH secretion via a Y1 receptor in frog melanotrope cellsEndocrinology143(5)1686-1694(2002).
[2]. Holzer, P., Reichmann, F., and Farzi, A.Neuropeptide Y, peptide YY and pancreatic polypeptide in the gut-brain axisNeuropeptides46(6)261-274(2012).
[3]. Shimizu, S., Azuma, M., Morimoto, N., et al.Effect of neuropeptide Y on food intake in bullfrog larvaePeptides46102-107(2013).
[4]. Preston, E., J?nsson, A.-C., McManus, C.D., et al.Comparative vascular responses in elasmobranchs to different structures of neuropeptide Y and peptide YYRegul. Pept.78(1-3)57-67(1998).