Glucose production by deconvolution in intravenous and oral glucose tolerance tests: role of output variable

Effects of kisspeptin on pathogenesis and energy metabolism in polycystic ovarian syndrome (PCOS)

Kisspeptin has been shown to participate in the regulation of pituitary hormone secretion and energy metabolism. In PCOS patients, there are disorders in pituitary hormone secretion and energy metabolism. The aim of this study was to investigate the serum kisspeptin and its relationship with abnormal metabolism in PCOS. This restrospective case-control study included 73 cases with PCOS and 63 control cases. All subjects were divided into obese and nonobese groups based on BMI. The serum kisspeptin levels, Cor, DHEA-S, plasma concentrations of glucose were tested. We found that the level of kisspeptin in PCOS group was higher than it in control group. The kisspeptin levels in nonobese PCOS group increased most obviously over than the other groups. The kisspeptin levels of all the subjects were positively correlated with LH levels, negatively correlated with the glucose-AUC, the insulin-AUC, and triglyceride levels. The findings of this study suggest that kisspeptin may play an important role in ovulation disorders in PCOS patients through regulating the level of LH and it could regulate the body's energy metabolism by regulating glucose and lipid metabolism.

NEFA minimal model parameters estimated from the oral glucose tolerance test and the meal tolerance test

The kinetics of nonesterified fatty acid (NEFA) metabolism in humans requires quantification to facilitate understanding of diseases like type 1 and 2 diabetes, metabolic syndrome, and obesity, and the mechanisms underpinning various interventions. Oral glucose tolerance tests (OGTT) and glucose meal tolerance tests (MTT) are potentially useful procedures for enabling quantification of NEFA kinetics because they both cause transitory, but substantial, declines and then rebounds in plasma NEFA concentrations in response to physiologically relevant increases in plasma glucose. The Boston MINIMAL model of NEFA kinetics was developed to analyze data from the intravenous glucose tolerance test (IVGTT), but in this work, we present for the first time its application to modeling NEFA data from both OGTT and MTT studies. This model enables estimation of SFFA (micromol.l(-1).min(-1)) (a parameter describing the maximum rate of lipolysis), and KFFA (%/min) (a parameter related to NEFA oxidation rate). The model could well describe the trajectories of NEFA concentrations following an OGTT (R2 in excess of 0.97) but was not as successful with the MTT (R2>0.65). Model parameters derived from analysis of OGTT and MTT data were well identified with coefficients of variation generally less than 15%. Type 2 diabetes, body mass index, and dietary treatment (high-fat vs. high-glycemic-index diets) were all shown to have significant effects on model parameters. Modeling plasma NEFA concentrations over 24 h has helped to identify and quantify the extent that periprandial NEFA peaks and nocturnal elevation in plasma NEFA can be accounted for by our model.