title: Determination of carbon monoxide (CO) in rodent tissue: effect of heme administration and environmental CO exposure.
abstract: Carbon monoxide (CO), produced endogenously during heme degradation, is considered a messenger molecule in vascular and neurologic tissues. To study this role, it is important to determine CO concentration in target tissues pre- and post-perturbations. Here, we describe a sensitive and reproducible method, which is linear and accurate, and provide some examples of its application for quantitation of CO concentrations in tissues pre- and post-perturbations. Tissues from adult rats and mice were sonicated (20% w/w), and volumes representing 0.04-8 mg fresh weight (FW) were incubated at 0 degrees C for 30 min with sulfosalicylic acid. CO liberated into the headspace was quantitated by gas chromatography. Tissue CO concentrations (mean+/-SD, pmol CO/mg FW) were as follows: blood (47+/-10, 45+/-5), muscle (4+/-4, 10+/-1), kidney (5+/-2, 7+/-2), heart (6+/-3, 6+/-1), spleen (11+/-3, 6+/-1), liver (4+/-1, 5+/-1), intestine (2+/-1, 4+/-2), lung (2+/-1, 3+/-1), testes (1+/-1, 2+/-1), and brain (2+/-1, 2+/-0) in untreated rat (n=3) and mouse (n=5), respectively. Between the rat and the mouse, only CO concentrations in the muscle and spleen were significantly different (p0.05). Endogenous CO generation, after administration of heme arginate to mice (n=3), increased CO concentrations by 0-43 pmol/mg FW. Exposure of mice (n=3) to 500 ppm CO for 30 min yielded significantly elevated CO concentrations by 4-2603 pmol/mg FW in all tissues over the native state. While blood had the highest CO concentration for all conditions, muscle, kidney, heart, spleen, and liver, all rich in hemoglobin and/or other CO-binding hemoproteins, also contained substantial CO concentrations. Intestine, lung, testes, and brain contained the lowest CO concentrations.
authors.affiliation: Department of Pediatrics, Division of Neonatal and Developmental Medicine, Stanford University School of Medicine, Stanford, CA 94305-5208, USA. henk.vreman@stanford.edu
authors.forename: Hendrik J
authors.initials: HJ
authors.lastname: Vreman
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Wong
authors.forename: Tomiko
authors.initials: T
authors.lastname: Kadotani
authors.forename: David K
authors.initials: DK
authors.lastname: Stevenson
mesh_terms: D000818:Animals; D001120:Arginine / Q000008:administration & dosage*; D002248:Carbon Monoxide / Q000032:analysis*; D002849:Chromatography, Gas / Q000379:methods*; D004781:Environmental Exposure; D006418:Heme / Q000008:administration & dosage*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D051381:Rats; D017208:Rats, Wistar
chemical_list: D006418:Heme; D002248:Carbon Monoxide; D001120:Arginine; C048849:heme arginate