Restitution of blood volume after hemorrhage: inhibition by somatostatin

To determine whether glucagon plays a significant role in the restitution of blood volume after hemorrhage, pentobarbital-anesthetized dogs were treated with somatostatin (SRIF). The administration of SRIF (14 micrograms/kg.h) prevented the increase in osmolality and the complete restitution of plasma protein and blood volume that normally occur after 10% hemorrhage. The intraportal addition of glucagon (20 ng/kg.min) during the initial 4 h after hemorrhage reversed the SRIF-induced block in hyperosmolality and was followed by complete restitution of plasma protein and blood volume. These data suggest that increases in glucagon may be a part of the multi-hormonal response to hemorrhage, and this may be a part of a reflex that mediates the homeostasis of blood volume.