The ultrastructure and the hormonal control of product synthesis in the hedonic glands of the red‐spotted newt Notopthalmus viridescens

Abstract

AbstractThe ultrastructure and the hormonal regulation of hedonic glands in male and in female red‐spotted newts have been studied throughout the year and under various experimental conditions. Hedonic glands are simple, alveolar, merocrine glands that contain a single layer of secretory epithelial cells surrounded by a discontinuous layer of myoepithelial cells. Although hedonic glands from both sexes are alike in form, females have only about a third as many as do males. While newts are in breeding conformation during the fall, winter, and spring, large quantities of a glycoproteinaceous product are sequestered within the lumina of their hedonic glands. During those seasons the secretory cells are cuboidal and contain abundant rough endoplasmic reticulum with dilated cisternae and active Golgi complexes. Secretory granules are numerous in the apical cytoplasm and appear to be attached to microfilaments and microtubules. During the summer months, secretory cells are quiescent and assume a columnar configuration, reducing the lumen to negligible proportions. Rough endoplasmic reticulum is sparse, residual secretory granules contain small vacuities, and lipid droplets and glycogen aggregates occur. Hedonic glands of newts in breeding conformation regress to the summer state within three to four weeks under laboratory conditions. In laboratory‐conditioned, gonadectomized male newts hedonic glands remain unchanged after treatment with saline, prolactin, or testosterone but are transformed to the breeding state by treatment with prolactin and testosterone in combination. Hedonic glands from ovariectomized females respond similarly to prolactin in combination with testosterone, but fail to respond to prolactin with estradiol.