The fate of glucosamine hydrochloride injected intravenously in man.

Glucosamine is known to be a constituent of the numerous mucocomplexes in man. These serve many important functions in the form of intercellular components, cementing substances, lubricants in joint and ocular fluids, and as aids to intestinal motility in the form of mucins of the alimentary tract. However, apart from a few very incomplete early reports on the fate of glucosamine in biological systems, there is little information available on the metabolism of glucosamine in man. This relative lack of knowledge has inspired the present investigation, namely, the development of an intravenous glucosamine tolerance test. The intravenous rather than the oral route was chosen to eliminate any error due to any breakdown or malabsorption of the compound in the alimentary canal, and because of early reports that oral glucosamine caused diarrhoea. Most of the information on the metabolism of glucosamine dates back to the earlier part of this century (Offer and Frankel, 1899; Fabian, 1899; Stolte, 1908). Experiments on human subjects carried out at about that time showed that the excretion of glucosamine into the urine began in the second hour after its ingestion and continued for a long period thereafter. Some conflicting results were obtained at the time. It was not until 1934 that Kawabe, using organic assay, traced the fate of orally and subcutaneously administered glucosamine hydrochloride in normal adult rabbits and found it to be distributed in the liver, kidney, and stomach mucosa as well as in the small intestine and the pancreas. Recently Boas and Foley (1955) injected glucosamine hydrochloride into rats, and found that 80% to 90% disappeared from the blood in 10 minutes. This occurred in the intact animal as well as in one in which the liver or kidney had been excluded from