Variations of lacrimal fluid peroxidase activity in female and male rats

Previous research from this laboratory showed that human lacrimal fluid per oxidase has cyclic variations during the menstrual cycle, correlated with p lasma levels of 17 beta -oestradiol. In the present investigation, variatio ns of enzyme activity and total protein content during the oestrous cycle o f young adult female rats are analysed. Effects from circadian rhythm and a gender-related influence are also examined. In female rats, as in women, l acrimal fluid peroxidase activity shows cyclic variations; in fact, it sign ificantly (p < 0.05) changes during the different phases of the oestrous cy cle. In contrast, in males such variations do not occur. Thus, we suggest t hat gender seems to exert a significant influence on the secretion of this specific tear protein, probably by a direct effect of oestrogens. Copyright (C) 2001 S. Karger AG, Basel.