Correlation between the Sex Hormone Binding Globulin Level and level of Insulin Resistance in Obese Prepubertal Children

Seenivasan, V (2006) Correlation between the Sex Hormone Binding Globulin Level and level of Insulin Resistance in Obese Prepubertal Children. Masters thesis, Madras Medical College, Chennai.


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INTRODUCTION: Insulin resistance is defined as an impaired ability of plasma insulin at usual concentrations to adequately promote peripheral glucose disposal, suppress hepatic glucose output and inhibit very low density lipoprotein (VLDL) output. Insulin resistance results in compensatory increase in insulin secretion. The resulting hyperinsulinemia overcomes the insulin resistance for sometime and keeps the blood sugar in normal range. However when relative beta cell insufficiency (insulin secretion insufficient for the level of hyperglycemia) also sets in, overt diabetes develops. Metabolic syndrome also known as Syndrome X is associated with increased risk of coronary heart disease and stroke. The features of metabolic syndrome include abdominal obesity, hyperinsulinemia, dyslipidemia, type 2 diabetes mellitus, and hypertension1. The core feature is elevated insulin levels which develops early in the course of disease. AIM OF THE STUDY: To correlate the level of sex hormone binding globulin with level of insulin resistance and (or) hyperinsulinemia in obese prepubertal children. DISCUSSION: The plasma SHBG concentration, originally considered to be under the direct regulation of sex hormone levels, is now considered to be under multi factorial regulation. Indeed, the basal production of SHBG seems to be steroid independent and more related to general metabolic factors and nutritional status58,59. In this sense some hormones such as growth hormone, insulin like growth factor (IGF)-I and insulin may play a more active role in the regulation of SHBG levels60. Recently, there has been increased interest in the role played by insulin in this multi regulation. It is now known that insulin has an inhibitory effect on synthesis of SHBG. By using cultured HepG2 cells, it has been found that insulin is potent inhibitor of basal production of SHBG. This action may by a direct mechanism or by indirectly increasing free fraction of IGF1. Any way, the relationship between insulin and SHBG is widespread phenomenon in adults61 and is present even in neonates62. Therefore, evidence suggests that it is a more physiological process than was originally thought63. Thus SHBG level could be a general marker for hyperinsulinemic insulin resistance. This would explain the observation that a low serum SHBG level is a strong predictor for development of NIDDM. Though numerous adult studies have already established negative correlation between insulin resistance and sex hormone binding globulin level, prepubertal period is ideal time to test the relationship. During pubertal progression, there are dynamic changes in the level of insulin resistance. Insulin resistance increased immediately at the onset of puberty (T2) but returns to near prepubertal level by the end of puberty (T5). Its peak occurs at T3 in both sexes64. Girls are more insulin resistant than boys at all pubertal stages. CONCLUSION: There is a strong negative correlation between SHBG and insulin resistant status. Low SHBG concentration is a stable integrated marker of insulin resistance and therefore has the characteristics to be potentially used as a surrogate measure of insulin resistance. Currently it is cost effective and also avoids the ordeals of measuring fasting insulin indices. For the time being the utility of SHBG estimation is limited to serial monitoring of insulin resistance in individuals on treatment after the presence of insulin resistance is established by conventional means. An extensive study with large sample size with cases and control is needed to determine the cut off value of SHBG for insulin resistance. With ethnic predisposition and drastic changes in life style there is spiralling incidence of metabolic syndrome in Indian population. Studies in the direction of searching such a useful surrogate marker of insulin resistance syndrome will have great impact in combating this epidemic.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Correlation ; Sex Hormone Binding Globulin Level ; Insulin Resistance ; Obese Prepubertal Children
Subjects: MEDICAL > Paediatrics
Depositing User: Ravindran C
Date Deposited: 20 Apr 2018 05:32
Last Modified: 20 Apr 2018 05:32

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