Abstract
Abstract: :
Purpose: Our previous studies have identified insulin in tears and insulin receptor in the human ocular surface and evaluated the influence of insulin on glucose metabolism of rat cornea. To investigate the regulatory mechanisms of insulin secretion in the ocular surface, the present study examined the insulin secretion time-course in rat tear film under glucose intravenous stimulation. Methods: Blood and tears were collected from Wistar male rats, 8 weeks old (n= 16), following a 12-hour fast and 5, 15, 30 and 60 minutes after intravenous glucose injection (1.0 g/kg of body weight). The samples were analyzed by radioimmunoassay for insulin level determination. Results: The insulin level in the tear film rose 500% after glucose stimulation and the peak was reached between 15 and 30 min. later, in contrast with blood insulin level that reached its highest point in between 5 and 15 min. Conclusion: These findings suggest that insulin secretion in the tear film is influenced by systemic conditions and may follow insulin blood levels.
Keywords: 376 cornea: tears/tear film/dry eye • 452 lacrimal gland