Antioxidant activity of melatonin in mice.

Melatonin (in gum tragacanth as solvent) was administered to mice in the dose range of 100 to 450 mg/kg intraperitoneally. It prevented the increase in plasma glucose resulting from pancreatic toxicity caused by the intravenous administration of alloxan at 40 mg/kg. This action of melatonin was significant and dose-dependent.

Protective effects of gamma-hydroxybutyrate on alloxan induced diabetes in mice.

Gamma-hydroxybutyrate (GHB) administered to mice prior to alloxan antagonizes its diabetogenic action in a dose dependent fashion and up to 96 hours after injection. Results are discussed on the basis of free radical formation by alloxan and of the metabolic property of GHB which is known to increase the rate of operation of the pentose phosphate pathway.

[New route of 2-N-(carboxypropylamino)-2-deoxy-D-glucopyranose synthesis].

A new route to 2-N-(carboxypropylamino)-2-deoxy-D-glucopyranose synthesis is reported, involving the Schiff-base derivative of beta-D-glucosamine with benzyl 4-oxobutyrate. Improvement in the synthesis of benzyl-4-oxobutyrate is also described. Biological compounds action was investigated by evaluating sedative and dopaminergic activities on male mice.

Brain tyrosine increases after treating with prodrugs: comparison with tyrosine.

After mice had been treated with L-tyrosine, O-phospho-L-tyrosine, L-tyrosine methyl ester or N-acetyl-L-tyrosine, tyrosine was assayed by HPLC coupled with fluorometric detection. O-Phospho-L-tyrosine behaved as a tyrosine prodrug after its hydrolysis by acid and alkaline phosphatases. After the intraperitoneal administration of O-phospho-L-tyrosine or the methyl ester, there was a substantial increase in bioavailability in terms of the effect of tyrosine.

Hepatic tyrosine aminotransferase inhibitor affects the bioavailability of exogenous tyrosine.

This study demonstrates the importance of controlling the activity of hepatic tyrosine aminotransferase when tyrosine is administered orally. The specific inhibition of this enzyme is proposed in the clinical use of tyrosine in syndromes related to deficient catecholaminergic transmission.