30 INSULIN RECEPTORS AS WELL AS INSULIN ARE PRESENT IN SALIVA AND NASAL MUCUS

• Published in: Journal of investigative medicine 2006-03, Vol.54 (2), p.S378-S378
• Main Authors: Henkin, R. I., Velicu, I.
• Format: Article
• Language: English
• ISSN: 1081-5589; 1708-8267
• DOI: 10.2310/6650.2005.x0015.108

We have recently demonstrated insulin presence in saliva and nasal mucus and that levels change in response to physiological and pathological processes. Because of these findings we wished to determine if insulin receptors were also present in saliva and in nasal mucus. We measured insulin receptor concentration (in ng/mL) by colorimetric ELISA 96-plate assay in plasma, saliva, and nasal mucus in fasting and nonfasting states in patients with a variety of diseases. Insulin receptors were present in plasma, saliva, and nasal mucus. In the fasting state in control patients insulin receptor concentration in plasma was 2.3 ± 0.3 (mean ± SEM), whereas in saliva it was 7.1 ± 0.6, significantly higher than in plasma (p < .001). In the fasting state in plasma in patients with controlled diabetes mellitus insulin receptor concentration was 21.0 ± 7.4; in saliva it was 4.0 ± 0.9, significantly lower than in plasma (p < .001). In the nonfasting state plasma insulin receptors in control patients were essentially the same as in the fasting state but in diabetics plasma insulin receptor concentration was decreased in the fasting state; in saliva, in control patients and in diabetics insulin receptor concentration was essentially the same in the fasting or nonfasting state. In nasal mucus in the nonfasting state in control patients insulin receptor concentration was 9.0 ± 1.0, about three times higher than in plasma, slightly higher than in saliva and more than twice as high as compared to diabetics. Insulin concentration relative to insulin receptor concentration in saliva in control patients and diabetics was decreased significantly comparing the nonfasting to the fasting state, whereas insulin itself was increased in both control patients and diabetics. In thin and obese patients there were changes in insulin receptor concentration in plasma, saliva, and nasal mucus relative to their physiological and pathological states. These data demonstrate that both saliva and nasal mucus contain soluble insulin receptors and indicate that these biological fluids can serve as indicators of insulin receptor metabolism. Since these fluids can be obtained with greater ease than can plasma, saliva and nasal mucus can serve as simple, useful, noninvasive indicators of insulin receptor as well as insulin metabolism. This is the first demonstration of insulin receptors in saliva and nasal mucus.