Starfish insulin.

Abstract

Acid–isopropanol extraction of digestive tissue from the starfish (Pisaster ochraceous) yielded material with properties resembling those of insulins from vertebrate species. The starfish extract enhanced glycogen deposition in mouse diaphragm tissue, with a dose–response slope similar to that of crystalline insulin from the ox; this specific effect of the starfish material was significantly reduced by a large excess of guinea pig antiserum to ox insulin, proving that the active starfish substance was insulin. The crude starfish insulin was similar to ox insulin in sensitivity to mercaptoethanol and was able to provoke cutaneous anaphylaxis in guinea pigs passively immunized with antiserum to ox insulin. Pseudoisocyanine-stained sections of starfish digestive tissue revealed metachromatic granules similar to those seen in mammalian β-cells.