Decrease in serum dopamine-beta-hydroxylase activity during oral glucose tolerance test
Obermann, Z.; Herzberg, M.
Israel Journal of Medical Sciences 14(7): 798-800
1978
ISSN/ISBN: 0021-2180 PMID: 681172 Document Number: 130134
The enzyme dopamine-.beta.-hydroxylase (D.beta.H), which converts dopamine to norepinephrine, is released into the blood, together with catecholamines, from the adrenal medulla and from sympathetic nerve endings. The effect of hyperglycemia and hyperinsulinemia following an oral glucose tolerance test on the activity of the D.beta.H was studied in diabetic and nondiabetic subjects. The changes in blood D.beta.H activity after oral glucose load in the diabetic subjects were shown. There was a significant decrease in D.beta.H activity in these patients 30-180 min after glucose intake. In the nondiabetic control subjects, only a small decrease in D.beta.H activity was noted at 30 min, but the difference from the zero time value was not statistically significant. The findings demonstrate a negative correlation between rising blood glucose levels and serum D.beta.H activity in diabetic patients. Determination of serum D.beta.H activity may be more useful in assessing the influence of glucose levels on norepinephrine release from the sympathetic nervous system than the cumbersome methods used for direct estimation of circulating catecholamines.