Follicular fluid was aspirated from atretic follicles in ovaries colle
cted from slaughterhouse and the concentration of acid and alkaline ph
osphatase measured. Acid phosphatase activities did not differ signifi
cantly in different sizes of atretic follicles while that of alkaline
phosphatase was higher and increased with follicular size. High concen
tration of alkaline phosphatase may be a characteristic of atresia in
large atretic follicles.