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Lacrimal fluid peroxidase activity during the menstrual cycle
F G Marcozzi1, F Madia, G Del Bianco
1Dip. Biologia di Base ed Applicata, Coppito1, Università de L'Aquila, Aquila, Italy.
Current Eye Research
|March 1, 2000
Summary
Human tear peroxidase activity fluctuates with the menstrual cycle, correlating with 17 beta-estradiol levels. Saliva peroxidase showed no such changes, suggesting a potential link to ocular disease predilection.
Area of Science:
- Ophthalmology
- Endocrinology
- Biochemistry
Background:
- Peroxidase enzymes play crucial roles in ocular surface defense.
- Hormonal fluctuations during the menstrual cycle can influence physiological processes.
- Understanding tear composition changes is vital for diagnosing and managing ocular conditions.
Purpose of the Study:
- To investigate peroxidase activity in human tears across different menstrual cycle phases.
- To compare tear peroxidase activity with salivary peroxidase activity.
- To explore the relationship between tear peroxidase and hormonal variations, specifically 17 beta-estradiol.
Main Methods:
- Collected tear and saliva samples from 10 healthy women over at least two menstrual cycles.
- Monitored menstrual and ovulation periods using body temperature and hormone level measurements.
- Assessed peroxidase activity using the Nbs-SCN method and protein content via the Bradford method.
Main Results:
- Tear peroxidase activity was significantly higher during preovulatory and luteal phases compared to menses (p < .05).
- A strong positive correlation was observed between lacrimal fluid peroxidase activity and plasma 17 beta-estradiol levels (p < .001).
- Salivary peroxidase activity did not exhibit estrogen-related cyclic variations.
Conclusions:
- Human tear peroxidase activity exhibits cyclic variations linked to the menstrual cycle.
- These variations appear to be influenced by 17 beta-estradiol plasma levels.
- Estrogen regulation of lacrimal peroxidase may contribute to the higher incidence of certain ocular diseases, like keratoconjunctivitis sicca, in females.