Kinetic arguments for the existence of a single form of intestinal ornithine decarboxylase during the postnatal development of normal and sparse-fur mutant mice and after EGF treatment

The Km for ornithine is remarkably constant during the course of postnatal development in both normal and spf mutant mice even if a large but transient increase in ornithine decarboxylase (ODC) activity is noted. Four hours after EGF injection (4 μg/g b.wt) to 17-day-old normal and spf mice, a marked stimulation of ODC activity is observed but Km remains unaffected. These data argue against the existence of multiple forms of ODC in the intestinal mucosa of mice.