Organ-culture studies of achondroplastic rabbit cartilage: evidence for a metabolic defect in glucose utilization.

Organ-culture studies were made using cartilage from achondroplastic (dwarf) rabbits (ac/ac) and their phenotypically normal litter-mates. A significantly higher incorporation of C from glucose and galactose was measured in the dwarf; incorporation of S from sulfate and H from thymidine was equal in the two types of explant. Also, CO2 and [ C]lactate production from glucose by the dwarf cartilage was increased. No difference in the ratio of CO2 evolution from [1C]and [6-C]glucose was found between the two cartilage types. Explants of dwarf cartilage utilized more glucose from the medium than did the controls. Radioautographs of tissue sections from the explants showed an increased number of grains from [C]glucose overlying the dwarf cartilage, and this difference was particularly great over the central portions of cartilage. The proportion of C grains from glucose was greater over the dwarf nuclei, less over the dwarf matrix and equal over the cytoplasm of the two tissues. Grain counts of sulfate and of thymidine did not differ in the two types of cartilage.