Metabolic studies of human bone in vitro. I. Normal bone.

Abstract

The feasibility of studying the cellular metabolic patterns of samples of fresh human bone obtained at biopsy by incubation in vitro was demonstrated. The metabolism in vitro of bone from normal adults remains constant for a sufficient time to allow quantitative estimates of the rates of certain metabolic processes including the biosynthesis of collagen. Metabolic rates in adult human bone samples obtained from a variety of ages and skeletal sites was similar when calculated on the basis of sample deoxyribonucleic-acid (DNA) despite considerable variation in cell content. The following rates of metabolism in the bone of normal adults, per mg of sample DNA/hour, were observed: O2 consumption, 0.47 [plus or minus] 0.09 [mu]mole; lactate production, 0.79 [plus or minus] 0.12 [mu]mole; incorporation of labeled proline into cells, 23.4 [plus or minus] 3.5 mumoles, into collagen, 0.24 [plus or minus] 0.04m[mu]moles; incorporation of labeled glucose into cells, 320.6 [plus or minus] 28.0 m[mu]moles, into collagen, 4.0 [plus or minus] 0.41 m[mu]moles. Metabolic patterns in human bone and of lower mammals (pigs and rats) was compared and their qualitative similarities noted. These similarities to justify the use of information from animal experiments to interpret phenomena observed in human samples. The implications of these observations for investigating the origins of human metabolic bone disease was discussed.