Joseph B. Foley

Effects of Growth, Fasting, and Trauma on the Concentrations of Connective Tissue Hexosamine and Water

Summary 1. The concentrations of hexosamine and water in connective tissue decrease with growth in the rat. There is a high degree of correlation between the concentrations of water and hexosamine in normal connective tissue. 2. Most traumatic agents (physical and chemical) effect a local non-specific increase in hexosamine and water concentrations. The degree of change of each of these constituents varies with the agent administered. Fasting does not influence this increase in hexosamine in response to local trauma, or the hexosamine concentration in untraumatized connective tissue. 3. Changes in the concentration of connective tissue hexosamine were not detectable following systemic stress (fracture).

Regulation of connective tissue hexosamine levels by the anterior pituitary and thyroid glands.

Summary 1. A decrease in the concentration of hexosamine in orbital connective tissue is observed with increasing age in normal rats but is abolished following thyroidectomy. It can be reversed, however, by the administration of thyroxin. The concentration of connective tissue hexosamine in hypophysectomized rats is similar to controls of the same age and is unaffected by either small or large doses of thyroxin. Growth hormone, on the other hand, produces an increase in the amounts of connective tissue and hexosamine with no change in the concentration of hexosamine. 2. It is suggested that the concentration and amount of hexosamine in orbital connective tissue in the rat is determined by a balance between the production of hormones of thyroid and anterior pituitary (growth hormone). 3. The response of rat orbital connective tissue to thyroidectomy or to the administration of pituitary extract appears to be less sensitive than that in the guinea pig.

Hypoglycemic Effect of D-Ribose in Man

Summary Infusion of D-ribose into normal man causes a marked decrease in blood glucose level which is not associated with significant elevation of blood pyruvate level or large decreases in serum inorganic phosphate concentration. Though the exact mechanism of this hypoglycemia is obscure the data appear to exclude increased peripheral glucose utilization and renal glucosuria as explanations of the ribose effect.†

Synthesis of hexosamine in the rat.

Summary 1. The relationship of carcass hexosamine concentration to age in growing rats showed that a marked decrease occurs between 10 and 80 days of age. 2. Hexosamine synthesis within the rat was demonstrated by means of balance studies on fasted animals and on animals fed diets containing very small or moderate amounts of hexosamine. 3. Supplementation of diets with moderate amounts of glucosamine-HCI had no effect on hexosamine levels in the carcass or excreta. 4. Hexosamines were demonstrated to occur in a number of semi-purified dietary proteins.

Fate of intravenously administered glucosamine in the rat.

Summary 1. Following the intravenous administration of glucosamine-HCl to the rat, 80-90% disappears from the blood within the first 10 minutes, in intact animals, as well as those in which the liver or kidneys have been excluded from the general circulation. 2. No destruction is evident when glucosamine is incubated with whole blood for 10 minutes. Glucosamine is destroyed, however, under neutral or alkaline pH conditions after a more prolonged period of time. 3. Intravenously administered glucosamine-HCl becomes rapidly distributed in all tissues of the body, with the greatest concentration increases appearing in the kidneys, liver, and intestines. In total amount, however, most of the administered dose is found in muscle, connective tissue, blood and liver. 4. Approximately 50% of intravenously administered glucosamine-HCl is destroyed in the body in a period of less than 1 hour.