HYDROLASES OF ANTERIOR SEGMENT TISSUES IN THE NORMAL HUMAN, PIG AND RAT EYE - A COMPARATIVE-STUDY

The distributions of the hydrolases acid and alkaline phosphatase (AP and ALP), N-acetyl-beta-D-glucosaminidase (NAG), beta-glucuronidase (b eta-Gluc), beta-galactosidase (beta-Gal), non-specific esterase (UE), dipeptidylpeptidases II and IV (DPPII and DPPIV), aminopeptidases M an d A (APM and APA), and gamma-glutamyltransferase (GGT) were investigat ed in the human, pig and Lewis rat normal anterior segment by histoche mical methods. The distribution of the above hydrolases, particularly that of proteases, varied between ocular tissues and between the three species. Lysosomal hydrolases together with GGT and ALP were consiste ntly active in the corneal epithelium, stroma and endothelium in all t hree species; the corneal distribution and activity of beta-Gal, APM, APA and DPPIV, however, displayed interspecies variation. The angular tissues showed similarities for most hydrolases with the exceptions of beta-Gal, UE, APM, APA and DPPIV. In all eyes examined strong ciliary epithelial activity for AP, beta-Gal, UE, GGT and ALP was observed in the pars plicata; only the pig eye also displayed strong DPPIV activi ty in this area. Regional differences in hydrolase distribution in the iris were observed in all species. A post-mortem freezing delay of lo nger than 24 h resulted in a decrease in hydrolase activity.