title: Effect of rate of hemorrhage on release of ACTH in cats.
abstract: The effect of rate of blood loss by acute hemorrhage (H) on adrenocorticotropin (ACTH) and cortisol plasma concentrations was assessed in anesthetized cats. Arterial blood was withdrawn at a rapid rate (10% blood vol/min) or at a slow rate (2%/min), and responses were compared across three volumes of H (10, 20, and 30% of blood vol). After rapid rate of H, ACTH increased in proportion to volume of H (r = 0.669, P less than 0.001) with a mean elevation of 124 +/- 27, 267 +/- 102, and 950 +/- 195 pg/ml for 10, 20, and 30% H, respectively. Slow rate of H evoked a significant increase in ACTH that was not proportional to volume of H (r = 0.314, P greater than 0.10), and the mean change during the post-H sampling period was 611 +/- 166, 828 +/- 302, and 1,070 +/- 239 pg/ml for 10, 20, and 30% H, respectively. Control animals showed no change in ACTH to the repeated sampling paradigm. Rapid H evoked an immediate decrease in mean arterial pressure (MAP) with a post-H recovery of MAP inversely proportionate to volume of H (r = -0.552, P less than 0.01). Slow H caused a progressive decrease in MAP with no significant post-H recovery of MAP at any volume of H. Cortisol concentration increased in proportion to volume of H after rapid H (r = 0.515, P less than 0.025), but not after slow H.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000097:blood*; D000818:Animals; D001794:Blood Pressure; D002415:Cats; D005260:Female; D006470:Hemorrhage / Q000097:blood / Q000503:physiopathology*; D008297:Male; D013997:Time Factors
chemical_list: D000324:Adrenocorticotropic Hormone