An endogenous peptide that stimulates lanthanum-resistant calcium uptake in vascular tissue.

A recent report has described the preparation of an extract from hemolyzed erythrocytes that has a stimulatory effect on lanthanum-resistant calcium uptake by vascular tissue in vitro and a hypertensive effect when injected into normotensive rats. The compound having a stimulatory effect on calcium uptake was further fractionated by molecular sieve and ion exchange chromatography, precipitation with CaCl2, high voltage paper electrophoresis, and high performance liquid chromatography (HPLC). HPLC yielded only a single fraction containing biological activity.

The effect of AMP on inhibition of muscle phosphorylase a by glucose derivatives.

Kinetic studies of the inhibition of rabbit muscle phosphorylase a D-glucan:orthophosphate alpha-D-glucosyltransferase (EC 2.4.1.

Regulation of the dephosphorylation of glycogen phosphorylase a and synthase b by glucose and caffeine in isolated hepatocytes.

Synergistic regulation of glycogen phosphorylase a by the competitive inhibitors glucose and caffeine in vitro indicates a possible physiological role for the negative effector site which binds caffeine (nucleoside site). In intact viable hepatocytes glucose promotes the phosphorylase a to be conversion by phosphorylase phosphatase. This conversion is considered to be a necessary prelude to the activation of glycogen synthase by phosphatase and of importance in hepatic regulation of glucose homeostasis.