Somatomedin generation by perfused livers.

Abstract

Publisher Summary This chapter discusses somatomedin (SM) generation by perfused livers. In the method described in the chapter, livers of normal and hypophysectomized rats weighing 85–150 gm were used. Livers were perfused with Waymouth's medium in a simple apparatus. Total liver ischemia was less than 10 seconds, and relatively normal lactate pyruvate levels were maintained in the perfusate. The apparatus permits recirculation of medium for any desired period and rapid change of medium. The SM activity on costal cartilages from a single hypophysectomized rat was measured. To establish a baseline against which to measure the effects of added GH, livers from both normal and hypophysectomized rats were perfused for a total of 3 hours with six 30-min changes of medium without added GH. The chapter presents the SO 4 uptake of cartilage incubated in the perfusates of livers of normal and hypophysectomized rats. Results are expressed as the percentage of the SO 4 uptake of cartilage incubated in medium alone. It was found that endogenous SM activity in the perfusates of the livers of normal rats (normal perfusates) was initially much greater than buffer levels and fell gradually to near-buffer levels over the first five medium changes.