AJP - Regulatory, Integrative and Comparative Physiology, Vol 255, Issue 5 851-R854, Copyright © 1988 by American Physiological Society
Evaluation of a blood sample-transfusion protocol in rats: blood gases, renin, and ACTH
H. Raff
Endocrine Research Laboratory, St. Luke's Medical Center, Milwaukee, Wisconsin 53215.
The present study evaluated a protocol for drawing large volumes of blood
over an acute time frame in conscious cannulated rats with blood from
cannulated donor rats simultaneously infused to maintain isovolemia. During
time control (n = 6), three successive 1.5-ml blood samples were drawn at
10-min intervals with equal volumes of donor blood infused simultaneously.
One milliliter of blood was drawn quickly and saved for analysis followed
by an additional 3 ml of blood withdrawal to total a 15-ml/kg hemorrhage.
Two subsequent 1.5-ml samples were replaced with autologous (hemorrhage)
blood. During hypoxia inspired O2 was decreased to 10% after the first
sample-transfusion. The sampling-transfusion protocol (time control) had no
effect on blood pressure (MAP), hematocrit (Hct), blood gases, renin, or
adrenocorticotropic hormone (ACTH). Hemorrhage resulted in a significant
decrease in MAP, Hct, base excess, and arterial PCO2 and an increase in
arterial PO2, renin activity, and ACTH. Ten percent O2 resulted in
significant hypoxemia, respiratory alkalosis, and a small degree of
hypotension at the 20-min sample with no change in renin and a moderate
increase in ACTH. The consistency of the results with previous studies
confirms the utility and efficiency of large sample-transfusion protocols
for the study of blood gas and endocrine dynamics in conscious rats.
