Morphology of female guinea pig Harderian gland during postnatal development - secretory endpieces

The main objective of this study was to investigate the morphological aspects of the development of the Harderian gland (HG) in the female guinea pig. A total number of thirty animals were used and divided according to age into groups, five animals each. Specimens were taken at the following ages; birth, one week, two weeks, three weeks, four weeks and two months postnatal. Histological, histochemical and immunohistochemical techniques were used. The gland was constituted of secretory end pieces and a duct system formed of intra-and extra-parenchymal ducts. At birth, the female guinea pig HG was active in the secretion of lipid and neutral mucin and the differentiation of several populations of cells (light and dark) was possible. However, its histological structure was still incomplete. The lining cells revealed many free ribosomes, a few and small organelles and large irregularly shaped nuclei and numerous mitotic figures. The secretory cells reached maturity by the age of three weeks, but growth in size continued up to the age of two months. They were light or dark; the light cells presented three forms that exhibited different morphological features. All modes of secretion (apocrine, merocrine and holocrine) were detected.