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No conversion of xanthine dehydrogenase to oxidase in canine cerebral ischemia.
Am J Physiol. 1990 Dec; 259(6 Pt 2):H1655-9.AJ

Abstract

Xanthine oxidase (XO) has been implicated as a source of free radicals mediating ischemia-reperfusion injury. Conversion of the non-free radical generating xanthine dehydrogenase (XD) to the free radical producing XO during ischemia has been demonstrated in several tissues. We examined the irreversible conversion of XD to XO in the dog brain after ischemia and after ischemia and reperfusion. Under pentobarbital sodium anesthesia and by use of a cerebrospinal fluid compression model of global cerebral ischemia, dogs were subjected to 30 min of ischemia (n = 8) or 30 min of ischemia and 60 min of reperfusion (n = 8). A cerebral perfusion pressure of 60 mmHg was maintained during reperfusion. Eight control dogs were not subjected to ischemia. After the dogs were killed their brains were rapidly removed and frozen in liquid nitrogen. XO and XD + XO activities were measured with a radioassay utilizing 8-[14C]hypoxanthine and separating substrate and products by thin-layer chromatography. Total XD + XO activity was significantly (P less than 0.05) decreased after ischemia and reperfusion (35.6 +/- 8.0 vs. 60.8 +/- 20.8 nmol.min-1.g protein-1 in controls, means +/- SD) but not after ischemia alone (48.2 +/- 20.4). XO/(XD + XO) was approximately 20% in all three groups. Irreversible XD to XO conversion is not an important mechanism leading to early tissue injury in global cerebral ischemia.

Authors+Show Affiliations

Diving Medicine Department, Naval Medical Research Institute, Bethesda 20889-5055.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

2260692

Citation

Mink, R B., et al. "No Conversion of Xanthine Dehydrogenase to Oxidase in Canine Cerebral Ischemia." The American Journal of Physiology, vol. 259, no. 6 Pt 2, 1990, pp. H1655-9.
Mink RB, Dutka AJ, Kumaroo KK, et al. No conversion of xanthine dehydrogenase to oxidase in canine cerebral ischemia. Am J Physiol. 1990;259(6 Pt 2):H1655-9.
Mink, R. B., Dutka, A. J., Kumaroo, K. K., & Hallenbeck, J. M. (1990). No conversion of xanthine dehydrogenase to oxidase in canine cerebral ischemia. The American Journal of Physiology, 259(6 Pt 2), H1655-9.
Mink RB, et al. No Conversion of Xanthine Dehydrogenase to Oxidase in Canine Cerebral Ischemia. Am J Physiol. 1990;259(6 Pt 2):H1655-9. PubMed PMID: 2260692.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - No conversion of xanthine dehydrogenase to oxidase in canine cerebral ischemia. AU - Mink,R B, AU - Dutka,A J, AU - Kumaroo,K K, AU - Hallenbeck,J M, PY - 1990/12/1/pubmed PY - 1990/12/1/medline PY - 1990/12/1/entrez SP - H1655 EP - 9 JF - The American journal of physiology JO - Am J Physiol VL - 259 IS - 6 Pt 2 N2 - Xanthine oxidase (XO) has been implicated as a source of free radicals mediating ischemia-reperfusion injury. Conversion of the non-free radical generating xanthine dehydrogenase (XD) to the free radical producing XO during ischemia has been demonstrated in several tissues. We examined the irreversible conversion of XD to XO in the dog brain after ischemia and after ischemia and reperfusion. Under pentobarbital sodium anesthesia and by use of a cerebrospinal fluid compression model of global cerebral ischemia, dogs were subjected to 30 min of ischemia (n = 8) or 30 min of ischemia and 60 min of reperfusion (n = 8). A cerebral perfusion pressure of 60 mmHg was maintained during reperfusion. Eight control dogs were not subjected to ischemia. After the dogs were killed their brains were rapidly removed and frozen in liquid nitrogen. XO and XD + XO activities were measured with a radioassay utilizing 8-[14C]hypoxanthine and separating substrate and products by thin-layer chromatography. Total XD + XO activity was significantly (P less than 0.05) decreased after ischemia and reperfusion (35.6 +/- 8.0 vs. 60.8 +/- 20.8 nmol.min-1.g protein-1 in controls, means +/- SD) but not after ischemia alone (48.2 +/- 20.4). XO/(XD + XO) was approximately 20% in all three groups. Irreversible XD to XO conversion is not an important mechanism leading to early tissue injury in global cerebral ischemia. SN - 0002-9513 UR - https://www.unboundmedicine.com/medline/citation/2260692/No_conversion_of_xanthine_dehydrogenase_to_oxidase_in_canine_cerebral_ischemia_ L2 - https://journals.physiology.org/doi/10.1152/ajpheart.1990.259.6.H1655?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -