Monoamine oxidase and semicarbazide-sensitive amine oxidase kinetic analysis in mesenteric arteries of patients with type 2 diabetes.
Monoamine oxidase (MAO, type A and B) and semicarbazide-sensitive amine oxidase (SSAO) metabolize biogenic amines, however, the impact of these enzymes in arteries from patients with type 2 diabetes remains poorly understood. We investigated the kinetic parameters of the enzymes to establish putative correlations with noradrenaline (NA) content and patient age in human mesenteric arteries from type 2 diabetic patients. The kinetic parameters were evaluated by radiochemical assay and NA content by high-performance liquid chromatography (HPLC). The activity of MAO-A and SSAO in type 2 diabetic vascular tissues was significantly lower compared to the activity obtained in non-diabetic tissues. In the correlation between MAO-A (K(m)) and NA content, we found a positive correlation for both the diabetic and non-diabetic group, but no correlation was established for patient age. In both groups, MAO-B (V(max)) showed a negative correlation with age. The results show that MAO-A and SSAO activities and NA content of type 2 diabetic tissues are lower compared to the non-diabetic tissues, while MAO-B activity remained unchanged. These remarks suggest that MAO-A and SSAO may play an important role in vascular tissue as well as in the vascular pathophysiology of type 2 diabetes.
Laboratory of Pharmacology, Faculty of Pharmacy, Coimbra University, Coimbra, Portugal.
S F
SF
Nunes
I V
IV
Figueiredo
J S
JS
Pereira
E T
ET
de Lemos
F
F
Reis
F
F
Teixeira
M M
MM
Caramona
D000368:Aged; D006631:Amine Oxidase (Copper-Containing) / Q000032:analysis / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000201:enzymology*; D005260:Female; D006801:Humans; D007700:Kinetics; D008297:Male; D008638:Mesenteric Arteries / Q000201:enzymology*; D008875:Middle Aged; D008995:Monoamine Oxidase / Q000032:analysis / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism
D006631:Amine Oxidase (Copper-Containing); D008995:Monoamine Oxidase; D009638:Norepinephrine