HISTOCHEMICAL SURVEY OF THE ANTERIOR SEGMENT OF THE NORMAL HUMAN FETAL AND ADULT EYE

The distributions of the lysosomal enzymes [acid phosphatase (AP), N-a cetyl-beta-D-glucosaminidase (NAG), beta-glucuronidase (beta-Gluc), be ta-galactosidase (beta-Gal), dipeptidylpeptidase-H (DPP II)] and of th e membrane-bound proteases [aminopeptidase M (APM), aminopeptidase A ( APA), gamma-glutamyltransferase (GGT), dipeptidylpeptidase IV (DPP IV) ] were investigated in the normal human adult and foetal anterior segm ent by histochemical methods. The distribution of these hydrolases var ied between ocular tissues. The most active enzymes in the adult corne al epithelium and endothelium were AP, beta-Gluc, NAG, beta-Gal and GG T; in the keratocytes, APM, APA, beta-Gluc and GGT predominated. The a dult trabecular meshwork cells were stained by AP, beta-Gluc, NAG, AP GGT, DPP II and DPP IV. The enzymes AP, beta-Gluc, APM and APA, howeve r, displayed greater activity in the endothelium of Schlemm's canal. T he adult ciliary epithelium stained strongly for all lysosomal hydrola ses; GGT was the most active protease here. Differences in enzyme acti vity were noted in some tissues when foetal and adult anterior segment s were compared. There appeared to be a decrease in the activity of so me enzymes with age and post-mortem delay greater than 24 h. The funct ion(s) of each enzyme and their possible roles in the respective tissu es are discussed.