Increase in gamma-glutamyltransferase level and development of established cardiovascular risk factors and diabetes in Japanese adults.

Background: We investigated the predictive value of changes in serum gamma-glutamyltransferase (GGT) for the development of cardiovascular disease (CVD) risk factors in Japanese.

Methods: A total of 1514 adult participants in a general health examination program were followed for 3 years until January, 2006. The subjects were divided into two groups according to whether their serum GGT level had decreased (< or =0 U/L) or increased (> or =1 U/L) from the baseline level of GGT during the study period.

Hepatic steatosis rather than visceral adiposity is more closely associated with insulin resistance in the early stage of obesity.

The aim of the present study was to investigate the specific relationship between hepatic steatosis and insulin resistance in the early stage of obesity. Among general health examinees who received an ultrasound scanning, 131 subjects without fatty liver (non-FL group) and 142 subjects with fatty liver (FL group) were selected so that both groups were matched for age, sex, body mass index, and % body fat. The FL group was then subdivided into 2 groups according to the severity of steatosis by ultrasound.

[Glucagon-like peptide-1(GLP-1)].

Glucagon-like peptide-1(GLP-1), an intestinal hormone secreted by L cells in response to luminal nutrients(carbohydrate and fat), enhances glucose-induced insulin secretion. Impairment of glucose-induced insulin secretion in patients with type 2 diabetes can be restored to near-normal by GLP-1 administration. In addition, GLP-1 possesses multiple biological effects which are favorable for the treatment of type 2 diabetes: inhibition of glucagon secretion, slowing of gastric emptying, reduction of appetite and food intake, upregulation of genes essential for insulin secretion(glucokinase, GLUT-2 etc), and beta cell proliferation and differentiation.

Adenosine triphosphate-sensitive potassium (K(ATP)) channel activity is coupled with insulin resistance in obesity and type 2 diabetes mellitus.

ATP sensitive potassium (K(ATP)) channels reside in the plasma membrane of many excitable cells such as pancreatic beta-cells, heart, skeletal muscle and brain, where they link cellular metabolic energy to membrane electrical activity. They are composed of two subunits, K+ ion selective pore (Kir) and sulfonylurea receptor (SUR). In addition to the central role of pancreatic beta-cell K(ATP) channels in glucose-mediated insulin secretion, several lines of evidence support the hypothesis that K(ATP) channels modulate glucose transport in the insulin target tissues.