In vitro secretion and hydroxylation of α-ecdysone as a function of the crustacean molt cycle

Abstract

With the use of an ecdysteroid-specific antiserum, the alterations in the hemolymph titer of molting hormones have been determined during the course of the molt cycle in the crab, Pachygrapsus crassipes. In addition, the in vitro secretory rate of the Y-organ has been determined as a function of the molt cycle. The rate of Y-organ secretion describes a pattern qualitatively similar to that of the hemolymph titer. The ability to hydroxylate the Y-organ secretory product (α-ecdysone) to the predominant circulating form of the molting hormone (β-ecdysone) is concentrated in the mitochondria-enriched fraction of the testes of the crabs, Pachygrapsus crassipes and Cancer antennarius. This hydroxylase activity increases during an induced premolt.