Insulin resistance is associated with hyperleptinemia, whilst exposure of hepatoma cells and isolated adipocytes to high concentrations of leptin has been demonstrated to result in attenuated insulin response and a reduced suppression of gluconeogenesis. To determine the acute metabolic effects of hyperleptinemia, we measured whole body glucose uptake (WBU) and hepatic glucose production rate (HGP) in rats using the euglycemic hyperinsulinemic clamping technique. Anesthetised male rats received recombinant murine leptin (1 microg/min) or vehicle into the jugular vein for 90 min. After 30 min of leptin infusion, insulin was infused to a level of 70 microU/ml and a variable-rate glucose infusion was adjusted to maintain blood glucose levels to 4-4.5 mmol/l. Glucose infusion rates during clamping were not different between leptin-infused and control rats, and there were no significant effects on the HPR or WBU measured using [6-(3)H]glucose under basal or clamped conditions. In summary, our data demonstrate that acute hyperleptinemia in normal weight Wistar rats does not appear to reduce insulin sensitivity, in vivo, or to affect HPR under clamp conditions.

Background C-peptide blood levels can indicate whether or not a person is producing insulin and roughly how much. C-peptide is secreted as a byproduct of the biosynthesis of insulin from proinsulin. C-peptide has proposed biological activity and a well-established diagnostic value. The significance of C-peptide concentration in the plasma and urine in the pediatric population needs further delineation. Aim To determine the significance of plasma C-peptide in obese African American adolescents with mild insulin resistance but no evidence of diabetes. Methods This study included 19 African American adolescents with body mass index (BMI) in at least the 85th percentile evaluated with anthropometric measurements, Homeostatic Model Assessment–Insulin Resistance (HOMA-IR) score, and oral glucose tolerance test (OGTT), and 24-hour urine collections. The study also included an age-matched control group of 15 healthy African American adolescent controls and were not subjected for OGTT. The correlation among BMI, fasting plasma C-peptide concentrations, and 24-hour–urine C-peptide concentrations was calculated. t Tests were conducted to compare plasma C-peptide and 24-hour–urine C-peptide concentrations for the test group and controls. Results Mean HOMA score (3.96 ± 1.84) signified mild insulin resistance among the adolescent test group. The test subjects exhibited adequate glucose tolerance (glucose range, 89.4–122.5 mg/dL) during the OGTT. A significant positive relationship was observed between BMI and fasting plasma C-peptide concentration in the control group (r = 0.537) but not the test group (r = 0.335). An insignificant positive relationship was exhibited between BMI and 24-hour–urine C-peptide concentration in the test group (r = 0.150) and controls (r = 0.254). Conclusions The positive relationship among BMI, plasma C-peptide, and urine C-peptide is worth further evaluation in studies conducting multiple rounds of OGTT with a larger sample of pediatric subjects. The potential diagnostic value of C-peptide may facilitate early detection of insulin resistance in the pediatric population.

A rapid, sensitive, stability indicating, reversed phase HPLC method for the quantitation of Metoclopramide and its related compounds is described. injected on a reverse phase CIS column with a mobile phase of 0.15M ammonium acetate and acetonitrile (80:20) w i t h W detection at 268 nm. The method is highly specific, sensitive and has the ability to separate Metoclopramide narnely, 4-acetylamino-5-chloro-N[2(diethylamino)ethyll-2-methoxybenzamide hydrochloride and 4-amino-5-chloro-2methoxybenzoic acid in quantities of up to 10 ucg/mL. is highly reproducible with average assay recovery of 104.7 2 1.1%.The sample is extracted in methanol and from its related compunds;The method 1365 Copyright 0 1989 by Marcel Dekker, Inc. Drug Dev Ind Pharm Downloaded from informahealthcare.com by McMaster University on 11/03/14 For personal use only.

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