Correlation between change in serum homocysteine levels during hyperinsulinemia and insulin sensitivity.

OBJECTIVE: To study the correlation between the changes in homocysteine (Hcy) levels during hyperinsulinemia and insulin sensitivity. MATERIAL AND METHOD: Forty-five subjects who underwent hyperinsulinemic euglycemic clamp were studied. Twenty-five subjects had normal glucose tolerance, seven had impaired glucose tolerance, and 13 had type 2 diabetes mellitus. Serum Hcy was measured before (Hcy 0) and at 120 minutes (Hcy 120) of glucose clamp. The change in Hcy levels during hyperinsulinemia was expressed as absolute difference between Hcy 0 and Hcy 120 (deltaHcy) and percentage difference over Hcy 0 (%deltaHcy). Insulin sensitivity index (ISI) was used to correlate with variables of interest. RESULTS: The ISI was not correlated with Hcy 0 and Hcy 120 but was correlated with deltaHcy and %deltaHcy. The deltaHcy and %deltaHcy were not significantly different between subjects with normal and abnormal glucose tolerance, whereas they were significantly different between subjects whose ISI were above and below the mean value. CONCLUSION: Although the change in Hcy levels during hyperinsulinemia was correlated with insulin sensitivity, the Hcy levels per se were not found to be correlated with insulin sensitivity. The change in Hcy levels during hyperinsulinemia was significantly different in subjects whose ISI was above and below the mean value but not in subjects with normal and abnormal glucose tolerance. This indicated that insulin resistance, not the glucose tolerance status, affected Hcy metabolism.

Screening for microalbuminuria in type 2 diabetes: a reconsideration.

To study the effect of timing of urine collection in determination of microalbuminuria in type 2 diabetic patients, timed urine (night time and daytime) as well as spot urine (first morning and random morning) samples were collected from 44 type 2 diabetic patients, 21 with normoalbuminuria and 23 with microalbuminuria. The methods of spot urine albumin expression for microalbuminuria were also compared between albumin concentration (AC) and albumin to creatinine ratio (ACR). Night time albumin excretion rate (AER) was 16 per cent lower and daytime AER was 13 per cent higher than 24-h AER (p<0.001). Forty-one (93%) of both night time and daytime urine samples had results corresponding with 24-h AER. For the spot urine, expression as AC showed a slightly stronger correlation with 24-h AER than expression as ACR. The levels of albumin in random morning urine samples were 50 and 35 per cent significantly higher than those in first morning urine samples when expressed as AC and ACR, respectively. In conclusion, because of low diurnal variation of AER, either daytime or night time urine could be used for screening of microalbuminuria in type 2 diabetes. Since mean albumin levels obtained from random morning urine were higher than those obtained from first morning urine, the cut-off level should be set higher in random morning urine in order to give comparable sensitivity in predicting microalbuminuria. The spot urine, either first morning or random morning urine, had a good correlation with the 24-h AER whether expressed as AC or ACR. Given the cost of the latter, the authors suggested measuring spot urine AC instead of ACR for screening of microalbuminuria in type 2 diabetes.