Crustacean Neurosecretory Hormones and Physiological Specificity

Abstract

Physiological effects of neurosecretory factors from crustaceans are examined for their hormonal specificity. Hyperglycemic hormone (HGH) from the eyestalk is a polypeptide, molecular weight about 7,000; it may activate phosphorylase and inhibit glycogen synthetase. Four pigmentary effectors (distal retinal pigment, melanophores, erythrophores and leucophores) respond to a peptide hormone (DRPH) having a molecular weight of 2,000. An earlier suggestion (Kleinholz, 1970) that light-adaptation of the distal retinal pigment and dispersion of pigment granules in chromatophores may be regulated by the same hormonal molecule is confirmed by test with synthetic hormone. Concentrators oferythrophore (ECH) and leucophore (LCH) pigments are peptides with respective molecular weights of 1,000 and about 1,500 daltons. Three factors which affect succinate oxidation by mitochondria appear in the three chromatographic zones eluted from G-25 Sephadex which contain DRPH, LCH and ECH, and therefore presumably are of about the same molecular size as the pigment hormones. The second and third of these factors have been shown to be distinctly different from the hormones with which they are initially eluted. Factors influencing hydromineral regulation, molt- and gonad-inhibition, cardiac activity, respiratory rates and lipid metabolism are reviewed.