Zink im Augenhintergrund des Seehundes

Abstract

The choroid membrane of carnivores, such as the dog, fox, cat, etc., contains a high concentration of Zn, which is localized in the tapetum lucidum cellulosum. In the dog and the fox the Zn occurs in combination with cysteine; this association does not hold in the case of the cat. Herbivores possess the tapetum lucidum fibrosum which contains no abnormal amounts of Zn. The Zn content of seal eyes is here investigated. In these eyes the tapetum is particularly well developed. It was found that the lens, vitreous body, retina and iris contained no abnormal amounts of Zn. The tapetum however contained exceptionally large quantities, the fundus of a single eye containing up to 10 mg Zn. The zinc was in combination with cysteine, and a complex of Zn-cysteine-water 1:1:1 was isolated. The Zn content of the tapetum reached 14.6% of the dry weight. No other organic ligands with Zn were detected.