l homocysteine/hypoxia

Myocardial hypoxia is thought to be an important stimulus for increasing interstitial adenosine concentration. The adenosine hypothesis of coronary control was investigated during steady-state hypoxia by making measurements of coronary venous and epicardial well adenosine concentrations in

This study was conducted to elucidate the role of S-adenosyl-L-homocysteine (SAH) hydrolase, 5'-nucleotidase and adenosine kinase in the production and removal of adenosine in the isolated guinea pig heart during normoxic (95% O2) and hypoxic (30% O2) perfusion. Using an adenosine kinase inhibitor

[35S]L-Homocysteine thiolactone ([35S]L-HCTL) was synthesized and its biodistribution evaluated as a potential brain radioprotective agent and as a tissue hypoxia marker. Drug uptake in mouse brain exceeded that in s.c. tumor 3 h post injection only. Multiple indicator dilution experiments in the

Hydrogen sulfide (H(2)S) is enzymatically generated in mammalian tissues from either L-cysteine or L-homocysteine. H(2)S possesses multiple biological activities, including regulation of vascular tone and blood pressure. Hydrogen sulfide produced in endothelial cells, vascular smooth muscle cells,

In order to quantify adenosine production from the transmethylation pathway [S-adenosylmethionine (AdoMet)----S-adenosylhomocysteine (AdoHcy) in equilibrium adenosine + L-homocysteine] in the isolated guinea-pig heart under basal conditions (normoxic perfusion with 95% O2) and during elevated

To assess the concentration of free intracellular adenosine in the heart the kinetic properties of cytosolic S-adenosylhomocysteine (SAH) hydrolase were utilized at elevated levels of L-homocysteine (adenosine + L-homocysteine in equilibrium with SAH + H2O). Global hypoxia was induced in the

S-Adenosylhomocysteine hydrolase of mammalian hearts from different species is exclusively a cytosolic enzyme. The apparent Km for the guinea-pig enzyme was 2.9 microM (synthesis) and 0.39 microM (hydrolysis). Perfusion of isolated guinea-pig hearts for 120 min with L-homocysteine thiolactone (0.23