Study of insulin to glucagon ratio and its correlation with thyroid hormones in streptozotocin induced type 2 diabetes.

Abstract

A number of endocrine hormones play a significant role in glycemic control of the body. Insulin and glucagon are two contrasting hormones which work in close association to maintain a normal fuel balance. Thyroid hormones also have a key role in regulating blood glucose levels. Several studies have suggested that type 2 diabetes mellitus (T2DM) have increased incidence of thyroid abnormalities. Objectives: To determine correlation between insulin to glucagon ratio and thyroid hormones levels in the two groups. Study Design: Randomized Control Trial. Settings: Physiology Department of Army Medical College, Rawalpindi and National Institute of Health (NIH), Islamabad. Period: 6 months (from 1^st January 2017 to 30^th June 2017). Material & Methods: A sample of sixty apparently healthy Sprague Dawley rats was selected randomly. It was divided into two groups i.e control and diabetic. It was ensured that all the rats were euglycemic and euthyroid at the start of the study by investigating serum thyroid stimulating hormone (TSH) and serum glucose levels. The control group was given with normal pellet diet whereas, STZ induced rats were fed on high fat diet while. The control group were injected with saline injection intraperitoneally after 2 weeks, while low dose of streptozotocin was injected to diabetic rats. The induction of diabetes mellitus was affirmed by checking plasma glucose levels and homeostatic model for insulin resistance (HOMA-IR). The specific diet was continued for another five weeks in both the groups. The terminal sample was investigated for plasma glucose using glucose oxidase method and serum insulin, TSH, T3 and T4 levels using ELISA technique. Results: The serum insulin and glucose levels were elevated in diabetic group as compared to the control group. HOMA-IR was also raised significantly in the diabetic group. The serum TSH and T4 levels were considerably higher (p˂0.001) while serum T3 was comparable in both the groups. There was no correlation between Insulin to Glucagon Ratio and TSH, T3 and T4 both in control and diabetic groups. Conclusion: Serum glucose, serum insulin and HOMA-IR were raised in the diabetic group. Serum TSH and T4 levels were also increased while no change in serum T3 levels. IGR and thyroid hormones were not correlated in either group.