Alkaline phosphatase in the cytoplasmic droplet of mammalian spermatozoa

The presence ofacid and alkaline phosphatase has been demonstrated biochemi-cally in bull spermatozoa (Roussel & Stallcup, 1966), and lysosomal acid phosphatases have been shown to occur in the cytoplasmic droplet of bull and ram spermatozoa (Dott & Dingle, 1968). Both types of phosphatases have also been shown histochemically in the spermatozoa of bulls (Krause, 1969) and several other mammalian species (Wislocki, 1949; Bern, 1949). Allison & Hartree (1969) have referred to acid phosphatase being concentrated in the acrosome of vertebrate and invertebrate spermatozoa but there appears to be no comprehensive information about the localization of alkaline phosphatase in spermatozoa. The present paper reports on such a localization in rabbit epidiy-mal spermatozoa. During an investigation into the histochemistry of the rabbit epididymis, it was noticed that the cytoplasmic droplets of epididymal spermatozoa reacted positively when stained with Gomori's method, using sodium-\g=b\glyceryl-phos-phate as the substrate. The reaction depended upon the pH being strongl