The adrenal gland of the African buffalo, Syncerus caffer: A light and electron microscopic study

Although the histology of the adrenal gland of many mammals, particularly domestic animals, is known, the histology of that of the African buffalo, Syncerus caffer, has not been described previously. Tissue from seven male and female adult buffalo was processed for light and electron microscopy. The gland is surrounded by a connective tissue capsule which contains smooth muscle fibres. The cortex of the gland is divided into three distinct zones with the cells of the outer zone being arranged in arcades rather than in glomeruli. The cells of this zona arcuata and of the outer region of the fasciculata have features typical of steroid-producing cells. The inner part of the fasciculata is a broad, less vacuolated and more intensely stained region than the outer region. Cells of the zona reticularis are arranged in freely anastomosing cords and are less vacuolated than the arcuata and the outer part of the fasciculata. The medulla is characterized by two distinct regions: an outer region of cells with granules of varying electron density which do not stain specifically with the Masson-Fontana technique and an inner zone of cells containing intensely electron dense granules which are chromaffin positive. These cells are adrenaline- and noradrenaline-secreting cells, respectively. The structure of the gland is thus typical of that of other mammals.