Our data clearly demonstrate that the postchallenge alteration of vascular function in patients with impaired glucose tolerance is caused by the acute elevation of glycaemia but not mediated by ADMA.

Background and Purpose-The C825T dimorphism of the gene encoding the human G protein ␤3 subunit (GNB3) is associated with hypertension and obesity. Although these findings suggest an association with insulin resistance and atherosclerosis, this hypothesis has yet been tested only partially. Methods-To investigate this hypothesis, the C825T dimorphism was determined in a population of 932 middle-aged white subjects of middle European (Austrian) origin. Insulin sensitivity was measured with the short insulin tolerance test; intima-media thickness of the carotid artery and morphological plaque burden were measured by ultrasound. Results-Insulin sensitivity was found to be significantly lower in carriers of the T allele (3.55Ϯ1.27 versus 3.92Ϯ1.30%/min, Pϭ0.012) in the group of male subjects with abdominal body fat distribution (waist-to-hip ratio Ͼ0.9). No effect was observed in women or men with a waist-to-hip ratio Ͻ0.9. Advanced carotid artery plaques were more frequent (odds ratio, 1.606; 95% confidence interval, 1.002 to 2.575; Pϭ0.04) in carriers of the T allele regardless of sex. No effect was observed with regard to carotid artery intima-media thickness. Conclusions-In summary, our results demonstrate that the GNB3 825T allele is associated with reduced insulin sensitivity in men with abdominal fat distribution and with more advanced carotid atherosclerosis in middle-aged white men and women.

Our results suggest that there is no association of the Glu298Asp polymorphism with coronary or carotid atherosclerosis or forearm vascular reactivity in these populations recruited in a country with a rather high risk for atherosclerosis. We suggest additional investigations to be performed in populations at different risk for coronary events to further elucidate the possible contribution of this polymorphism to vascular disease.

Compared to conventional human premixed insulin the prandial therapy with biphasic insulin aspart results not only in an improvement of glucose tolerance but also in a significant reduction of postprandial hyperlipemia.