Carbonic anhydrase in the vitreous body.

REVIEWS of some recent literature concerning the biochemistry of the vitreous body contain no references to the presence of enzymes (Bellows, 1952, 1953; von Sallmann, 1953, 1954; McLean, 1954). However, the possibility of the existence of enzymes in the vitreous body has not been overlooked. Lepine (1870) reported that the vitreous of dogs, rabbits, and frogs contained a substance which caused hydrolysis of starch, and Michel and Wagner (1886) mentioned that they had looked for "fibrinferment" in the vitreous but had found no evidence of its presence. Leber (1903) reported the presence in the vitreous of an amylase, and Lo Cascio (1922) found an amylase, catalase, and enzymes catalysing proteolysis, the reduction of methylene blue, and the hydrolysis of glyceryl monobutyrate; and, recently, anabolic enzymes have been demonstrated in the vitreous by Zeller (cited by Schwartz and Leinfelder, 1955). Bakker (1941) reported briefly that the vitreous body of some mammals contains a minute amount of carbonic anhydrase. The occurrence of this enzyme in ocular tissues has become of great interest since Becker (1954) demonstrated that the systemic administration of a carbonic anhydrase inhibitor (acetazoleamide, Diamox) often reduces the intra-ocular pressure in both normal and glaucomatous eyes. Carbonic anhydrase is known to occur in the lens (Bakker, 1939, 1941), in the ciliary body and iris (Wistrand, 1951; Gloster and Perkins, 1955), and in the retina (Leiner, 1940; Bakker, 1941; Kauth and Sommer, 1953). The experiments described in this paper were carried out to determine the carbonic anhydrase content of the vitreous of the rabbit and to investigate the relative amounts of the enzyme in the peripheral and central regions of the vitreous body.