Alkaline Phosphatase in Various Cell Types of the Anterior Pituitary of the Guinea Pig

ONLY small amounts of alkaline phosphatase have hitherto been found in mammalian endocrines. It was, however, possible to demonstrate considerable quantities of this enzyme in the anterior pituitary lobe of both the male and the female guinea pig. After fixation of the glands in 96 per cent alcohol, in 80 per cent alcohol, in acetone or in pyridine-alcohol1, the Gomori technique2 was used. As already known, the nuclei of the anterior pituitary show a positive reaction which, however, has not been localized to any particular cell type3. In order to identify the type of cells containing the phosphatase, every two of four paraffin sections (thickness : 2–4μ) of each gland were examined as to content of phosphatase : the two other sections were stained by Masson‘s trichrome (acid fuchsin, Ponceau 2R and aniline blue) method.