Effects of bleeding on mitochondrial ultrastructure in the avian kidney

Three levels of hypovolemia were produced in awake and anesthetized domestic chickens by withdrawing 2.5, 5.0, or 10.0 ml blood per kg body weight. A commercial indirect blood-pressure monitor was unable to detect significant differences between hemorrhaged birds and age-matched controls. Perfusion-fixed kidney samples from unanesthetized birds had mitochondrial low-amplitude swelling in proximal tubular epithelial cells. This response was slight at the lowest bleeding level but was definite at the middle and marked at the highest bleeding levels.