Effects of Leptin on Insulin Sensitivity in Normal Rats*

• DOI: 10.1210/endo.138.8.5327
• Publication Date: 2014-01-08T16:09:00Z
• Authors: W. I. Sivitz; S. A. Walsh; D. A. Morgan; M. J. Thomas; W. G. Haynes
• Keywords: Blood Glucose; Epididymis; Leptin; Male; 0301 basic medicine; Glucose Transporter Type 4; Time Factors; Monosaccharide Transport Proteins; Body Weight; Muscle Proteins; Proteins; Infusion Pumps, Implantable; Rats; Rats, Sprague-Dawley; 03 medical and health sciences; Glucose; Adipose Tissue, Brown; Hyperinsulinism; Animals; Insulin; Insulin Resistance; Insulin-Like Growth Factor I

Abstract To determine whether leptin has insulin sensitizing effects in normal rodents, we measured plasma glucose and concentrations male Sprague-Dawley rats treated with or vehicle by continuous sc infusion for 48 h. In additional experiments, examined the acute effect of iv upon sensitivity under conditions clamped glycemia. Subcutaneous was administered at 10.0 1.0 μg/h. avoid confounding differences food intake, both leptin- vehicle-treated were fasted during 48-h period infusion. Infusion leptin, 10 μg/h, significantly reduced insulin. Leptin, also decreased insulin, although on did not achieve statistical significance. Leptin either dose alter body weight epididymal fat mass compared controls. circulating insulin-like growth factor-1 levels. No GLUT-4 content brown observed as a result leptin-treatment. urine osmolality, increased water renal potassium excretion vehicle-infused rats. rats, determined whole utilization hyperinsulinemic clamps performed targets 60 90 mg/100 ml. Glucose 29% last 135 min glycemia ml (P < 0.05) 30% mg/dl 0.01) infused vehicle. summary, fasting presence hyperinsulinemia glucose. These appear dependent altered weight. salt metabolism resulting intake more dilute urine.