Alterations in glycosaminoglycan metabolism in β-aminopropionitrile-treated chick embryos

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Abstract
1. Na235SO4, [1-14C]glucosamine and [1-14C]acetate were used as precursors of the sulphated glycosaminoglycans to study the biochemical effect of β-aminopropionitrile in chick embryos. The incorporation of all three precursors was decreased in the treated embryos between days 7 and 10 of embryonic development. No inhibition of incorporation of these precursors occurred between days 16 and 20 of embryonic development at the dosages of β-aminopropionitrile used. 2. β-Aminopropionitrile treatment also decreased the amount of N-acetylhexosamines in the chick embryo and decreased the percentage of the hexosamine esterified by nucleotides. Respiration was decreased by homogenates prepared from treated embryos. Likewise, UDP-xylosyl- and UDP-galactosyl-transferase activities were decreased in treated embryos and cartilage from embryos and growing chicks. 3. The data suggest that β-aminopropionitrile, in addition to the known lathyrogenic activity, either is or gives rise to a potent metabolic poison that interferes with basic cellular metabolism. The results are consistent with a decreased rate of ATP generation as an explanation for the decrease in glycosaminoglycan synthesis.