The hexose monophosphate shunt mechanism was found to be a (and probably the) major pathway for in vivo bovine cerebral glucose oxidation. Isotope studies showed a 6.5:1 (5.0-7.2:1) ratio for the contributions of glucose C-1 and C-6, respectively, to cerebral CO2. HTO production from glucose-6-T paralleled C-14-O2 produced from glucose-6-C-14.
Arterially isolated brain perfusion was accomplished with fresh homologous arterial blood, utilizing calves as experimental animals. Albumin-I-131 leakage studies and perfusion angiography confirmed the completeness of cerebral arterial isolation during perfusion of a single common carotid artery at +20 mm. Hg pressure above systemic arterial pressure. Plastic injection models of the bovine cephalic arterial tree demonstrated anastomoses adequate to permit the necessary flow alterations.