The in Vivo and in Vitro Biosynthesis of Lung Tissue Glycopeptides

The biosynthesis of lung tissue glycopeptides in normal and vitamin A-deficient conditions was studied. Parallel to the change in the differentiative pattern in vitamin A deficiency there was a drastic decrease in the incorporation of glucosamine tagged with carbon 14 (¹⁴C) into a fucosecontaining glycopeptide. An anaplastic benzo[a]pyrene-induced tumor of the lung, transplanted in hamsters treated with excess retinoic acid, showed an increased glucosamine ¹⁴C incorporation into glycoproteins when incubated in vitro. Normal lung tissue was not affected by excess retinoic acid in its glycoprotein biosynthetic capacity.