Changes in calcium response to hormones in single hepatocytes during culture

Abstract

Many hormones and growth factors exert their actions on liver by generating certain compounds termed second messengers. Recently, it has become clear that Ca²⁺ can also act as a second messenger, and some hormones exert their actions through Ca²⁺. The increase in intracellular Ca²⁺ causes a very large number of cellular changes. To clarify the significance of Ca²⁺ signalling in hepatocytes, we measured Ca²⁺ response to hormones in primary cultured hepatocytes. There was remarkable Ca²⁺ response to vasopressin and phenylephrine early after seeding, but the Ca²⁺ response weakened, delayed and disappeared during culture. It is known that the numbers of V₁-vasopressin and α₁-adrenergic receptors on the surface of hepatocytes decrease during culture. This decrease in receptor numbers will reduce Ca²⁺ response in hepatocytes, and this change in signal transductian will induce the alteration of the generation of physiological response in growth and differentiation.