Relationship of thyroid hormones with serum fasting insulin and insulin resistance in euthyroid glycemic anomalies

A total of 277 euthyroid subjects,diagnosed as normal glucose tolerant,impaired glucose tolerant,and type 2 diabetic pakistani subjects were sampled and analyzed for metabolites and data was worked out to investigate the relationship of thyroid hormones and insulin resistance in the glycemic anomalies. oral glucose tolerant test (ogtt) was employed to confirm the glycemic status. the subjects were categorized using diabetes expert committee criteria (2003). thyrotropin (tsh),total triiodothyronine (tt3),total thyroxin (tt4) and insulin were assessed by enzyme linked immunoassays (elisa). fasting plasma glucose and hbalc were measured by glucose oxidase and low pressure cat ion exchange chromatography. homeostasis model of assessment (homa-ir) was employed to assess the level of insulin resistance. anthropometric measurement and habits were recorded. younger glucose intolerant subjects were highly hyperinsulinemic and insulin resistant as compared to the diabetic group (p<0.05).serum concentration of tt3 was significantly low in igt and diabetic group as compared to ngt (p<0.05). serum concentration of tsh was significantly higher in igt and diabetic group. a significant inverse correlation of fasting serum insulin and insulin resistance with t3 prevailed in the nomal glucose tolerant subjects (r= -0.45.,r=.345 p<0.05). in multiple regression analysis when insulin was a dependent variable tt4 and tsh were significant predictors of insulin secretions in igt and diabetic groups respectively p<0.05. the homeostatitic relationship of insulin and t3 has been lost with the parallel development of insulin resistance and hyperglycemia in glycemic anomalies. the ratio of insulin and t3 is important in glucose homeostasis. copyright 2011 zoological society of pakistan.