Background :
@EN Adenosine deaminase(ADA) is a purine metabolic enzyme that specifically catalyzes the deamination of adenosine. Adenosine acts directly to stimulate insulin activity via several processes such as glucose transfort, lipid synthesis, pyruvate
dehydrogenase activity, leucin oxidation, and cyclic nucleotide phosphodiesterase activity. Therefore, ADA is suggested to be an important enzyme for modulating the bioactivity of insulin, and its activity is composed of two ADA isoenzymes with
differing properties - ADA1 and ADA2. A previous study that serum levels of ADA, particularly ADA2, were elevated in both insulin dependent diabetes mellitus (IDDM) and non-insulin dependent DM(NIDDM) patients. However the significance of the
elevated
ADA level in diabetes mellitus(DM) is not understood at the present time. The purpose of this study was to determine the correlation of elevated serum ADA and its isoenzyme activities to fasting serum insulin level, glycemic control, and diabetic
chronic complications in NIDDM patients.
@ES Method :
@EN The serum levels of ADA isoenzymes (ADA1 and ADA2) in normal controls(NC, n=29) and NIDDM(NIDDM, n=32) patients were measured by Biancolle ADA kit, ADA1 inhibitor {erythro-9-(2-hydroxy-3-nonyl)-adenine hydrochloride}, and
autoanalyzer(Ciba-Corning
Co., U.S.A.).
@ES Results:
@EN The mean serum levels of ADA in NC and NIDDM patients were 15.7±4.5 and 20.6±6.1 units/L, respectively(p<0.001) and those of ADA2 in NC and NIDDM patients were 12.4±4.2 and 17.0±4.2 units/L respectively(p<0.001). Serum ADA activity in
NIDDM
patients was positively correlated with the fasting serum insulin level(r=0.29, p<0.001), and the HbA1c level(r=0.31, p<0.001). Serum total ADA activities in NIDDM patients without (n=19) and with chronic diabetic complication(n=13) were
19.9±6.3
and
21.7±6.0 units(L(NS) respectively, and those of serum ADA1 and ADA2 in NIDDM patients without and with chronic diabetic complications were 3.3±1.6 and 4.1±2.1 units/L(NS), and 16.6±5.6 and 17.6±4.9 units/L(NS).
@ES Conclusion:
@EN Serum levels of ADA, particularly ADA2 were elevated in NIDDM patients and positively correlated with serum fasting insulin levels and with HbA1c levels. However serum ADA activities were not correlated with diabetic chronic complications.
Measurement of serum ADA activities, especially ADA2 may be important to understand the pathophysiological aspect of NIDDM patients.
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