Influence of Vitamin D and Starvation on Cartilage Glycogen and Serum Calcium and Phosphate

Summary

Glycogen content of the rachitic rat tibial epiphyseal cartilage is determined during healing induced by vitamin D or starvation. Rachitic rat cartilage contained 8.61 μmoles glycogen per gram net weight of tissue. Following a single dose of vitamin D (4000 I.U.) the glycogen content was not significantly altered at 24 hours, but was decreased to 6.16, 5.50 and 4.45 μmoles at 48, 72 and 96 hours respectively. Fasting caused a rapid decrease in the glycogen content to 4.45 and 2.50 μmoles at 24 and 48 hours respectively. Vitamin D treated rat cartilage oxidized glucose to a greater extent than the corresponding untreated controls. It is suggested that glucose and glycogen metabolism stimulates the formation of calcifiable matrix by the cartilage cell. Fasting for 48 hours caused a marked fall in serum calcium and a rise in serum phosphorus level.