Variations in the glycosylation of the collagen synthesized by chick embryo cartilage. Effects of development and several hormones.
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abstract
Cartilage from chick embryos was incubated with [14C]lysine and the relative amounts glucosylgalactosyl[14C]hydroxylysine and galactosyl[14C]hydroxylysine in the collagen of the tissue were assayed. The ratio of glucosylgalactosyl[14C]hydroxylysine to galactosyl[14C]hydroxylysine in the collagen synthesized in vitro increased with age when cartilage from 7-, 8-, 9-, and -day-old embryos was compared. The ratio was slightly less with cartilage from 12-day-old embryos than with cartilage from 10-day-old embryos. Cartilage homogenates from 8-day-old embryos were found to contain larger amounts of substrate for collagen glucosyltransferase than cartilage homogenates of 10-day embryos, indicating that the cartilage from the younger embryos contained more protein-bound galactosylhydroxylysine. Also, it was shown that homogenates of 9-day-oldchick embryos contained more collagen glucosyltransferase activity than homogenates of 8-day-old embryos, even though the homogenates contained about the same levels of collagen galactosyltransferase activity. Further experiments indicated that the ratio of glucosylgalactosyl[14C]hydroxylysine to glaactosyl[14C]hydroxylsine in the collagen synthesized by the tissue was decreased by thyroid hormones, hydrocortisone, growth hormone, and -animo-propionitrile. The results emphasize the large heterogeneity of the collagen synthesized by the same tissue under slightly different biological condiotions. 1970.
