Mobilization of intracellular calcium by glucagon and cyclic AMP analogues in isolated rat hepatocytes

Abstract

Separate or combined addition of cyclic AMP-dependent and Ca²⁺-linked hormones to isolated rat hepatocytes suspended in a low Ca²⁺ medium reduced the total cellular Ca. When the hormones were administered together, their effects were not additive. This suggests that both types of hormones mobilize Ca²⁺ from a common intracellular pool. In the presence of 1.8 mM extracellular Ca²⁺, the Ca²⁺ influx counterbalanced or even exceeded the hormone-induced Ca²⁺ loss, depending on the ability of the hormones to stimulate the Ca²⁺ influx.