Relationship of adipokine to insulin sensitivity and glycemic regulation in obese women: The effect of body weight reduction by caloric restriction
Authors: Velojic-Golubovic Milena , Dimic Dragan , Antic Slobodan , Radenkovic Sasa , Djindjic Boris , Jovanovic Miodrag 
Published: March 2013

Bacground/Aim. Visceral fat is highly active metabolic and endocrine tissue
which secretes many adipokines that act both on local and systemic level. It
is believed that adipokines and "low-grade inflammatory state" represent a
potential link between obesity, metabolic syndrome, insulin resistance and
cardiovascular disease. Leptin and adiponectin are considered to be the most
important adipokines with the potential metabolic and cardiovascular effects.
Body weight loss improves insulin sensitivity and decreases risk for most
complications associated with obesity. The aim of this study was to determine
the effects of moderate loss of body weight on the level of leptin and
adiponectin, insulin sensitivity and abnormalities of glycoregulation in
obese women, to determine whether and to what extent the secretory products
of adipose tissue, leptin and adiponectin contribute to insulin sensitivity,
as well as to assess their relationship and influence on glycemia and
insulinemia during the period of losing body weight using a calorie
restricted diet. Methods. The study involved 90 obese female subjects (BMI ??
30 kg/m2) of different age with weight loss no less than 5% during a
six-month period by application of restricted dietary regime. The calorie
range was between 1,100-1,350 kcal. Serum levels of leptin and adiponectin,
fasting glucose, fasting insulinemia, and Homeostasis Model Assessment of
Insulin Resistance (HOMA-R) index were determined in all the subjects
initially and after weight reduction. The presence of glycemic disorders was
assessed on the basis of oral glucose tolerance test - OGTT. Results.
Applying a 6-month restrictive dietary regime the subjects achieved an
average weight loss of 8.73 ? 1.98 kg and 8.64 ? 1.96%, which led to the
reduction of fasting glycemia, fasting insulinemia and HOMA-R index at the
maximum level of statistical significance (p < 0.001). The achieved reduction
led to a statistically significant decrease of leptin level and increase of
adiponectin level (p < 0.001). The correction of the established pre-diabetic
disorders of glycoregulation was not statistically significant. There was a
statistically significant correlation between the anthropometric parameters,
leptin, adiponectin, fasting glycemia, fasting insulinemia and HOMA-R index.
There was a positive correlation between leptin, fasting insulinemia and
HOMA-R, as well as a statistically significant negative correlation between
adiponectin, fasting insulinemia and HOMA-R index (p < 0.01). Conclusion.
Body weight increase and central fat accumulation lead to changes in serum
levels of leptin and adiponectin, reduction of insulin sensitivity and
development of glycemic dysregulation. Secretory products of adipose tissue,
leptin and adiponectin contribute to the genesis of these disorders. The
obtained results show that the effect of adiponectin on insulin sensitivity
is more significant. The analysis of the effects of weight loss on the
investigated parameters shows that moderate weight reduction by restrictive
dietary regime lead to changes of investigated parameters at the maximum
level of statistical significance. Such results emphasize the importance of
weight reduction in obese persons, as well as the need for consistent
implementation of restricted dietary regime in the process of treatment of
obesity.