Arginine is a physiological precursor of endothelium-derived nitric oxide.

ATP dose dependently stimulated the formation and release of nitric oxide (NO) from perfused rabbit aorta. L-Canavanine, an inhibitor of various L-arginine-utilizing enzymes, abolished basal and ATP-induced NO formation and release. ATP increased the accumulation of presumably NO-derived NO2- in the medium of primary cultures of bovine aortic endothelial cells. 15NO, 15NO2- and 15NO3- formation was found when L-[guanido-15N2]arginine was added to the culture medium. We conclude that the terminal guanidino nitrogens of L-arginine are the physiological precursors of endothelium-derived NO.

[Occurrence of carbon monoxide, carbon dioxide and nitrogen oxides during the use of gas stoves]. / Auftreten von Kohlenmonoxid, Kohlendioxid und Stickstoffoxiden beim Betrieb von Gasherden.

The concentrations of carbon monoxide, carbon dioxide, nitrogen monoxide and nitrogen dioxide arising from gas burning have been measured under experimental and field conditions. In the test room propane, butane and town-gas have been burned, whereas in the apartments investigated only town-gas has been used. The most important influence on the concentration of the four substances arises from the changes in the burning conditions of the flame. Laboratory experiments have been carried out in the test room with open flames and with an aluminum block or a kettle on the flame. The following results have been obtained: (a) for CO the lowest concentration is obtained with open flames irrespective of the type of gas burned. Higher concentrations have been found with aluminum blocks, whereas the highest concentrations were associated with the use of kettles and pots, (b) the experimental conditions have only a small influence on the CO2 concentration, (c) NO concentrations are influenced by the gas type and by the experimental conditions. They are low with kettles but high with open flames, (d) NO2 concentrations are less influenced by the experimental conditions than are NO concentrations. The results of more than 1000 paired determinations of NO2 in kitchen and other rooms are presented. The concentrations which have been measured using diffusion tubes according to Palmes which were exposed for 48 h, were highest in kitchens of dwellings fully equipped with gas devices (heating, cooking, warming water). The mean value of the concentrations was about 50 micrograms/m3, whereas the mean for dwellings without any gas device has been found to be lower than 20 micrograms/m3.