APOCRINE SECRETION IN THE INFRAORBITAL GLAND OF THE JAPANESE SEROW, CAPRICORNIS-CRISPUS - A SCANNING ELECTRON-MICROSCOPIC STUDY

The infraorbital gland of the Japanese serow was examined under the scanning electron microscope to clarify the nature of apocrine secretion. The size and number of apocrine blebs on secretory cells varied markedly from cell to cell; as the size of blebs increased, their numbers decreased. After pinching off of blebs, crown-shaped structures were retained on the remaining apical surface of secretory cells. Detached free blebs in the lumen were spherical in shape with smooth surfaces. Secretory cells having blebs of similar size formed small clusters in tubules, and these clusters consisted of cells without blebs, cells with small blebs, cells with medium-sized blebs and cells with large blebs. The present evidence obtained by scanning electron microscopy is very much in harmony with results obtained at the light-microscopic level in terms of the sizes and numbers of blebs during apocrine secretion. Moreover, our evidence suggests the capacity for production of variously sized blebs in secretory cells and the presence of segmentary differences, in terms of apocrine activity, in tubules.