Elevation of glucosamine 6-phosphate synthetase activity in Bleomycin-induced pulmonary fibrosis in hamsters.

The single intratracheal instillation of bleomycin sulfate (0.5mg (potency) per 100g body weight) in hamsters rapidly increased the activity of glucosamine 6-phosphate synthetase (EC 2.6.1.16) of the lung, a major regulatory enzyme for the synthesis of acidic glycosaminoglycan (AGAG). The activity increased as early as day 2, reached maximum level at day 10, then decreased and returned to the control level at day 45. The content of AGAG was also in creased by bleomycin treatment, but the increase of AGAG followed the elevation of the enzyme activity. These results suggest that the early elevation of glucosamine 6-phosphate synthetase activity is closely related to the accumulation of AGAG in the fibrosing lung caused by bleomycin.