Influence of Parathyroid Extract on the Metabolism of Organic Acids by Bone Slices

Abstract

Slices of femur from rabbits receiving parathyroid extract and slices of bone from control rabbits were incubated in Krebs HCO₃ buffer with various C¹⁴-labeled substrates. Compared to control slices, experimental tissue converted up to two thirds less succinate, citrate, fumarate and glutamate and up to twice as much glucose and lactate to C¹⁴O₂. When hypotonic tris buffer was used, the yield of C¹⁴O₂ from fumarate and citrate was lower than with HCO₃ buffer, and no difference was found between control and experimental slices. In the presence of about 10^-5 M 2,4-dinitrophenol, bone slices produced 2–3 times more C¹⁴O₂ from glucose than when dinitrophenol was absent, and the tissue from parathyroid-treated animals still exhibited the same percentage increase in C¹⁴O₂ yields over the control tissue. With 5 × 1O^-4 M dinitrophenol, however, the yield of C¹⁴O₂ was depressed, and slices from hormone-treated animals produced about the same amount of C¹⁴O₂ as did control tissue. At all concentrations, dinitrophenol inhibited the yield of C¹⁴O₂ from fumarate. The relationship of these data to the possible mode of action of parathyroid extract is discussed. (Endocrinology74: 133, 1964)