Turkish Journal of Endocrinology and Metabolism, (2005) 2 : 55 - 58 55 ORIGINAL ARTICLE Relation Between Leptin and Insulin in Patients with Type 2 Diabetes Mellitus Javad Mohiti * Doudi Qujuq** * Yazd Diabetes Research Center, Shahid Sadoughi University of Medical Science, Yazd, IRAN. ** Baboul university of medical science, Babul ,Iran Leptin and insulin are reported to control glucose metabolism therefore, a relationship between these two hormones should reveal the metabolic effect of these hormones on glucose metabolism. In this study, the relationship between leptin and insulin was evaluated in obese diabetes type 2, BMI>30 kg/m2 (group A), and non- obese diabetes type 2 patients, BM<25kg/ m2 (Group B). Study design: 49 subjected were studied. Of these, 32 subjects (4 male and 28 female) were (group A) and 17 subjects (8 male and 9 female) were (group B) and analyzed for Leptin, Insulin, and HbA1c. Results: The results obtained showed leptin, insulin and HbA1c levels of 5.16± 1.2 μg/ L and 21.8±11.2 μg/L, 6.75±1.2 μIu/ml and 10.4 μIu/ml and %9.38 ± 0.56 and %8.76 ± 0.36 in groups B and groups A, respectively. Discussion: The results of this study show that plasma concentrations increased with the percentage of body fat and to body mass index. Plasma leptin in obese diabetes, in comparison to non-obese diabetes individuals, was four times higher (p=0.001). Statistical analysis indicates a direct correlation between fasting blood leptin and insulin (r=0.290 p=0.005) in group B, while this correlation is reverse in group A. Key words: leptin,insulin,diabetes,obesity, Resistance, HbA1c Introduction Leptin, a 16 kDa circulating hormone produced and released primarily by adipose tissue. Leptin exerts a regulatory control mechanism on food intake via inhibition of neuropeptide Y and increases the basal metabolism rate with selectively promoting fat metabolism. (1) Leptin has two types of receptors; the long form and humorous short form. At the beginning direct leptin actions were thought to be exclusively confined to the central nervous system (CNS). It is now clear that there are multiplicities of peripheral target organs such as the pancreas, skeletal muscle, liver and gastrointestinal system (2,3). Leptin appears to play a range of roles as a growth factor in a number of different cell types, such as a mediator of energy expenditure and most importantly to interact with other hormonal mediators and regulators of energy and metabolism such as insulin, glucagon, growth hormone and glucocorticoids (5,6,7). A large body of evidence indicates that leptin along with insulin exert an inhibitory effect on food intake, and an activation effect on the regulation of thermogenesis within the central nervous system (4,14). Leptin and insulin function as a critical signal to the brain in the long-term regulation of energy homeostasis (14,16). The exact relationship between leptin and insulin is not clear and is sometimes controversial (8,9). Some researchers failed to show a direct effect of leptin on the energy homeostasis (10), while other studies focused on the relationship between leptin and insulin, which share many properties as adiposity signals. Although insulin is secreted from pancreatic beta cells rather than from adipocytes, the secretion of both Correspondence address: Javad Mohiti Corresponding author: Javad Mohiti, Yazd diabetes Research Center, Joomhori Avenue, Yazd, IRAN. E-mail : mohiti_99@yahoo.com Tel: +98 351 822 61 28 Tel: 09 133 52 81 32 Fax: +98 351 525 83 54