- The androgenic gland has been described in a variety of crustacean species—isopods, amphipods and decapods. It has been shown to play a role in the regulation of male differentiation and in the inhibition of female differentiation. Upon its application for endocrine manipulation, it inhibits female characteristics. Recently, the androgenic hormone from the isopod Armadillidium vulgare was purified and characterized on the basis of a morphological bioassay. The hormone is a glycosylated protein composed of two peptide chains connected each to the other by two disulfide bridges. The pro-hormone consists of the same two chains connected by a third peptide in a complex that resembles the insulin super family hormones. The study of the androgenic gland in decapods lags behind that in the isopods, and a decapod androgenic hormone has yet to be identified. In this review, five decapod species are described as models, in which the androgenic gland exerts morphological, anatomical, physiological and behavioral effects. These models could serve as the basis of possible bioassays for the study of the structure and mode of action of the androgenic hormone in decapod crustaceans.