Vascular transport of insulin to rat cardiac muscle. Central role of the capillary endothelium.

AUTOR(ES)

Bar, R S

RESUMO

Using intact, beating hearts, we have assessed the interaction of insulin with capillary endothelium and the subsequent appearance of insulin in cardiac muscle. Rat hearts were perfused with 125I-insulin (10(-10) M) alone or in combination with unlabeled insulin (10(-9)-10(-5) M). 125I grains (shown to represent greater than 90% intact insulin) over both capillary endothelium and cardiac muscle decreased in a dose-dependent manner when hearts were co-perfused with labeled insulin and increasing concentrations of unlabeled insulin. Perfusion of 125I-desoctapeptide (DOP) insulin, a low affinity insulin analogue, with unlabeled insulin (10(-9)-10(-5) M) had no effect on the appearance of 125I-DOP insulin over microvessel endothelium and muscle. When capillary receptors were first destroyed by trypsin treatment or blocked by anti-receptor antibodies, the appearance of 125I-insulin in cardiac muscle decreased proportional to the inhibition of insulin binding to the capillary receptors. We conclude that insulin binding to capillary endothelial receptors is a central step in the transport of intravascular insulin to rat cardiac muscle.

Documentos Relacionados

• The role of vesicles in the transport of ferritin through frog endothelium.
• Role of actin and myosin in the control of paracellular permeability in pig, rat and human vascular endothelium.
• The vascular endothelium. A new horizon.
• Vascular cell adhesion molecule 1: contrasting transcriptional control mechanisms in muscle and endothelium.
• Desialation of transferrin by rat liver endothelium.