Haemorrhage-induced secretion of active and inactive renin in conscious and pentobarbitone-anaesthetized sheep.
The response of plasma levels of active and inactive renin to haemorrhage was investigated in sheep with indwelling artery and vein catheters. In conscious animals, loss of 10% of estimated blood volume over a 5 min period increased plasma active renin by a mean of 59%, a surprisingly small change. Plasma inactive renin also increased, but only by 86%. Maximum increases in both forms of renin occurred within 1 h of the haemorrhage. The effects of an equivalent blood loss were investigated in pentobarbitone-anaesthetized sheep maintained in an upright posture using padded slings. Anaesthesia per se had no effect on plasma active or inactive renin. In anaesthetized sheep, 3 h after haemorrhage, plasma active renin had increased by 403% and inactive renin by 299% above control values, but a plateau (maximum) response was not reached during this time. In both conscious and anaesthetized animals the haemorrhage-induced increases in active and inactive renin occurred in parallel. It appears that haemorrhage of this intensity is a comparatively mild stimulus to increase plasma renin concentration in conscious sheep but is much more effective in anaesthetized animals. This may be linked to anaesthetic-induced increases in prostaglandin synthesis within the kidney.
D000768:Anesthesia, General; D000818:Animals; D005260:Female; D006470:Hemorrhage / Q000097:blood*; D007668:Kidney / Q000378:metabolism; D008297:Male; D010424:Pentobarbital / Q000494:pharmacology*; D011311:Pressoreceptors / Q000502:physiology; D011453:Prostaglandins / Q000502:physiology; D012083:Renin / Q000097:blood* / Q000378:metabolism; D012756:Sheep
D011453:Prostaglandins; D012083:Renin; D010424:Pentobarbital