Recent studies have shown the insulin-like effect of vanadyl sulphate or sodium ortho
(or meta-)vanadate administered orally to rats. Toxicity of these drugs and reluctance
by the animals to drink the solutions and take food, concerning the amelioration of
some diabetes syndrome discussed in 1994 by Domingo et al. (1), McNeill et al. (2)
and Wiliams and Malabu (3), prompted us to investigate a new vanadate complex: disodium
bis(oxalato)oxovanadate(IV), Na2[VO(OX)2] · H2O. The main object of the experiment was to study whether this complex administered
as 3 mmol/l solution in 0.5% NaCl during 7 days could act on the subcellular level
and influence the activity of liver Golgi membrane galactosyltransferase activity.
Free blood sugar level was lowered (but was still higher than in the control group)
in diabetic rats after seven days of vanadate action and was accompanied by lowered,
however not statistically significant, serum triglyceride levels. The yields of isolated
Golgi-rich membrane fractions were about half of the level in diabetic groups (untreated
and treated with vandium) compared with the control groups. Purity of these membrane
fractions, expressed as nmol Gal transferred per mg of proteins and per h, was the
same in four groups investigated and showed the possibility to compare them. Activity
of galactosyltransferase calculated in nmol Gal transferred per 1 g of liver and per
1 h or per whole liver in the same time (as a possibility of glycosylation of the
secretory and membrane glycoproteins) was lower in both diabetic groups. However,
after vanadium treatment (D + V group), the activity was higher than in untreated
diabetic rats (D group) in three of five investigated animals. Vanadyl-oxalate complex
did not normalize in a statistically significant manner the enzyme activity which
was significantly lower in diabetes than in control. This is similar to insulin influence
on the galactosyltransferase activity reported previously by Kaczmarski et al. in
1981 (4) and Kordowiak et al. in 1981 (5).
Key words
Bis(Oxalato)Oxovanadate(IV) - Liver Golgi Galactosyltransferase (GalT) - Streptozotocin-Diabetes
- Vanadium
