Carbohydrate metabolism and concentration profiles of solutes in the canine lumbar intervertebral disc

Utilization of glucose and oxygen by the cells as well as concentration profiles of solutes were studied in the canine intervertebral disc. Cell metabolism in this avascular tissue, being predominantly anaerobic, was found to be dependent on oxygen tension (this being especially pronounced in the region of 0.13-0.4 kPa (1-3 mmHg). A high production rate of lactic acid was found in the nucleus pulposus, whereas towards the periphery of the annulus fibrosus this rate gradually decreased. In the centrally located areas of the disc tissue, far away from the blood circulation, the highest concentrations of lactic acid were found. For the normal disc the energy demands seem to be met as even small amounts of oxygen account for a large energy source, whereas the cellular requirements are balanced up predominantly by glucose. In regions with extremely low oxygen tensions large amounts of glucose are consumed, but an additional potential energy pool of glycogen seems to be available.