Methylguanidine

METHYLGUANIDINE (methylguanidin), HN = = C(NH₂)-NH-CH₃, a strongly alkaline, amorphous crystalline mass; found in meat extract (Kutscher, Gulevich), in liver, blood, urine; formed during meat putrefaction (Brieger); contained in cultures of cholera vibrios on meat medium. Obtained artificially by oxidation of creatine or creatinine with mercury oxide or its acetate, with oxalyl-methylguanidine [HN = C(NH₂) N(CH₃) CO-COOH] (Baumann, Ingvaldsen) as an intermediate oxidation product, which is also contained in muscle tissue (Gulevich); it is possible that M. is formed in the body by the same path. Contrary to the opinion of Ewins, Smorodintsev and A. proved that M. is present in the body in an unformed state, and not as an artificial product of chemical processing. Asymmetric dimethylguanidine HN=C(NH₂)-N(CH₃)₂ was also found in urine (Kutscher, Lohmann); after removal of the parathyroid glands, symmetric dimethylguanidine HN = C(NH-CH₃)₂ was also discovered in urine (Koch). These observations, in connection with the toxicity of M. and its derivatives mentioned here, led a number of authors to an as yet insufficiently substantiated assumption that the tetany observed after removal of the parathyroid glands is a consequence of self-poisoning of the body as a result of disruption of its guanidine metabolism. According to Krimberg and Komarov, M. is a hormone that causes the secretion of digestive juices and enhances intestinal peristalsis.