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The number of goblet cells in the small intestine decreased in the vitamin A-deficient rat. Incorporation of 14C-d-glucosamine into a fucose-containing glycopeptide declined markedly. Ultracentrifugation of this glycopeptide in H2O gave only a single component, with a sedimentation value of 3.6 S, whereas, in 0.1 mphosphate buffer (pH 7.5) two components appeared, with much higher sedimentation constants (6.2 S and 7.2 S).

In vivoand in vitroexperiments demonstrated that rat liver cells are able to synthesize a double-labeled mannolipid from [3H]retinol and GDP-[14C]mannose. The double-labeled mannolipid was purified by DEAE-cellulose, silicic acid, and thin-layer chromatography, and shown to contain retinol and mannose in a molar ratio in the range of 1:1.

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.