Glucosamine 6-Phosphate Synthesis in Normal and Neoplastic Rat Tissues

Abstract

The amidotransferase forming glucosamine 6-phosphate is demonstrable in many but not all rat tissues. It is highest in liver after birth and in certain transplanted tumors. All tumors that were examined contained some of the enzyme, but not in amounts that parallel any recognizable tumor characteristics. Comparisons with earlier analyses may point to unresolved analytical discrepancies in certain tissues.

Glucosamine synthetase activity of the colonic mucosa in ulcerative colitis and Crohn's disease.

“…There was more glucosamine synthetase in the colonic mucosa than in several samples of human liver tissue that were assayed by the same method (9-20 ,umol glucosamine synthesised/h/g wet wt compared with 4-10 units in liver tissue). This contrasts with previously reported animal experiments in which the levels of glucosamine synthetase in the intestine were lower than those in the liver (Kaufman et al, 1971;Kikuchi et al, 1971) but those measurements were apparently made on full thickness intestine including the muscle layers. Normal rnflamed mucosa Normal mucosa synthesis.…”

“…1 Glucosamine synthetase levels (in pumol glucosamine synthesised/h/g wet wt) in normal colonic mucosa, obtained from the normal cut ends of25 colectomy specimens (22 removedfor carcinoma of the colon and three for localised diverticulitis), andfrom the rectal biopsies of 20 patients with the irritable colon syndrome. of the colour of glucosamine (Kaufman et al, 1971) but this was ignored and the glucosamine-6phosphate synthesised was expressed as if it were glucosamine in the Morgan-Elson reaction. The units of enzyme activity were umol glucosamine synthesised/h/g wet wt of tissue.…”

“…There is feedback inhibition of glucosamine synthetase by UDP-N-acetylglucosamine (Kornfeld et al, 1964). Glucosamine synthetase has previously been measured in experimental animals, where it has been found principally in liver and also in the stomach and the intestine, but with none detectable in muscle (Kaufman et al, 1971;Kikuchi et al, 1971). There is no published work on its activity in human tissue.…”

UDP-N-acetylglucosamine transferase and glutamine: fructose 6-phosphate amidotransferase activities in insulin-sensitive tissues

“…Early studies utilizing the colorimetric spectrophotometric assay to assess GFA found no significant activity in either heart or skeletal muscle [16,17] but did find as in the present study, that GFA activity was higher in the submandibular gland than in the adult rat liver [16]. The highest GFA activities have been reported in the gut [16].…”

REGULATION OF ENZYMES IN ANIMALS: EFFECTS OF DEVELOPMENT PROCESSES, CANCER, AND RADIATION. Progress Report VI, May 1, 1971--April 30, 1972

“…Almost every enzyme studied in this way reveals problems. Glucosamine synthetase was measured in many tissues (7). It persists in all tumors, but its assay needs improvement.…”