RESUMO
Mesolimbic areas such as nucleus accumbens, amygdala and septal nuclei are known to influence food intake and body weight. However, the reports on gender difference in the neural regulation of obesity and energy homeostasis are incomplete. Therefore, the present study was conducted to assess the effect of lesions of nucleus septal medialis (NSM) and the gender difference of lesion on food intake (FI), body weight (BW), serum lipid profile, thyroid profile, glucose and insulin levels and glucoseinsulin ratio (GIR) in Wistar albino rats. Twenty-four rats were divided equally into control and experimental groups having 6 male and 6 female rats in each group. In the experimental group, bilateral electrolytic lesion of NSM was performed by stereotaxy and post-lesion parameters were recorded. In the control group, sham-lesions of NSM were produced. Following lesion, blood glucose and serum insulin levels were decreased and GIR was increased significantly in female rats, but not in male rats. It was concluded that NSM is involved in energy homeostasis, especially in female rats.
RESUMO
Various brain areas like the ventromedial hypothalamus (VMH) are known to influence food intake and body weight. Though obesity is more common in females, the reports on gender difference in the neural regulation of energy homeostasis are not adequate. Therefore, the present study was conducted to assess the gender difference in the effect of VMH lesion on food intake (FI), body weight (BW), serum lipid profile, thyroid profile, glucose and insulin levels and glucose-insulin ratio (GIR) in Wistar albino rats. Twenty-four Wistar albino rats were divided equally into control and experimental groups with 6 male and 6 female rats in each. In the experimental group, bilateral electrolytic lesion of VMH was performed by stereotaxy and post-lesion parameters were recorded. In the control group, VMH sham lesion was made. Male-female difference in each parameter was determined. Following VMH lesion, FI was increased (females, P<0.01) and BW (males, P<0.05) and GIR decreased in males (P<0.001), which was significantly correlated with BW. T3 was more significantly correlated with FI and BW in females (P<0.000 and P<0.001). Following VMH lesion, male rats exhibited significant weight gain in the absence of proportionate hyperphagia indicating that weight-gain was mainly metabolic in nature. Also, the male rats developed more susceptibility to insulin resistance. The female rats developed resistance to weight-gain inspite of hyperphagia, which could be due to the higher T3 level.
RESUMO
PURPOSE:We performed this study to compare correlation between the indices of insulin resistance using fasting insulin and glucose level and body mass index (BMI), and to determine the clinical usefulness of glucose/insulin ratio (G/I ratio), which is easily available in clinical base. METHODS:Total 119 children with simple obesity, whose BMI is over 95th percentile, were evaluated. We calculated G/I ratio, logInsulin, HOMA-IR, logHOMA-IR, and QUICKI and evaluated their relationship to BMI. RESULTS:Children with high-degree obesity had higher insulin resistance than children with mild to moderate-degree obesity (logInsulin, 1.13+/-.23 vs 1.27+/-.29; logHOMA-IR, 0.46+/-.24 vs 0.61+/-.30; QUICKI, 0.33+/-.03, 0.31+/-.03)(P<0.01), and pubertal children had higher insulin resistance than prepubertal children (G/I ratio, 7.39+/-.07 vs 4.85+/-.29; logInsulin, 1.14+/-.27 vs 1.31+/-.22; logHOMA-IR, 0.47+/-.28 vs 0.65+/-.22; QUICKI, 0.33+/-.03 vs 0.31+/-.02) (P<0.001). BMI had correlation coefficient as -0.436 for QUICKI, -0.432 for G/I ratio, 0.430 for logInsulin, and 0.425 for logHOMA-IR (P=0.000). G/I ratio was well correlated with QUICKI (r=0.901, P=0.000), logHOMA-IR (r=-0.865, P=0.000), and logInsulin (r=0.899, P=0.000). The changes of BMI were correlated with changes of G/I ratio (r=-0.547, P<0.01), QUICKI (r=-0.464, P=0.01), and logHOMA-IR (r=0.429, P<0.05). CONCLUSION: This study revealed that the degree of BMI had statistically significant correlation with insulin resistance, which can be reflected by G/I ratio, logHOMA-IR and QUICKI. G/I ratio was well correlated with logHOMA-IR and QUICKI, which suggests that G/I ratio could be used as an bedside index of insulin resistance. The changes of G/I ratio were more correlated with changes of BMI than those of logHOMA-IR and QUICKI.