The leydig cell in larval amphibian epidermis. Fine structure and function

Abstract

Abstract The large, presumably mucus and/or fluid secreting cells of Leydig have been studied in the epidermis of the newt, Taricha torosa , by light and electron microscopy. Mitotic activity in visibly differentiated Leydig cells results in their increasing numbers so that by mid‐larval stages they comprise the major cellular component of tailfin skin. Subsequently, the number of these cells diminishes as the epidermis thickens; their final disappearance coincides with metamorphosis and epidermal cornification. During the course of larval life, clear vesicles within Leydig cell cytoplasm accumulate granular material and, in time, assume the morphology of typical mucous aggregates. Concomitantly, the cytoplasm progressively becomes clear in appearance and nearly devoid of organelles. The surface of larval skin is normally provided with a thin mucous coat by continual production on the part of apical epidermal cells. When this surface is exposed to air, observation over a period of time reveals that the outer mucous coat hardens rapidly. There is no indication that additional fluid or mucus is provided to the drying surface from Leydig cells. Rather, light and electron micrographs of epidermis after various degrees of desiccation suggest that Leydig cells do respond to drying, but do so by adding fluid and perhaps mucous material to subsurface, extracellular compartments of the epidermis. The concept that Leydig cells provide an internal fluid reserve is discussed in relation to epidermal development and prevailing physiological and structural evidence bearing on intercellular compartments.