IN-VIVO ESTIMATION OF CEREBRAL BLOOD-FLOW, OXYGEN-CONSUMPTION AND GLUCOSE-METABOLISM IN THE PIG BY [O-15]WATER INJECTION, [O-15]OXYGEN INHALATION AND DUAL INJECTIONS OF [F-18] FLUORODEOXYGLUCOSE

There is a need for suitable non-primate laboratory animals for studie s of brain function by positron emission tomography (PET). To provide a comparative index of the circulatory physiology of the pig, we have applied novel PET tracer methodology to seven anaesthetized pigs, and measured cerebral regional oxygen consumption (CMRO2), cerebral blood flow (CBF), and cerebral glucose metabolism (CMRglc). Blood flow and f low-metabolism couple were estimated for selected cerebral regions of interest. We found an average hemispheric CMRO2 of 171+/-18 mu mol/100 cm(3)/min. Individual hemispheric CBF measurements varied between 33 and 41 ml/100 cm(3)/min, with an average of 37 +/- 3 ml/100 cm(3)/min at an average Pa-CO2 of 4.3+/-0.9 kPa. The blood flow dependency on ar terial P-CO2 was calculated from the results of the carbon dioxide res ponse in two pigs in which the CBF measurements obeyed the equation CB F (ml/100 cm(3)/min)= 8.9 Pa-CO2 (kPa). In each pig, CMRglc was studie d twice with a double-injection FDG method. In the first session, the values of CMRglc averaged 27 +/- 3 and 23 +/- 3 mu mol/100 cm(3)/min, estimated by multilinear and linear regression analysis, respectively. In the second session, the corresponding averages were 27 +/- 3 and 2 4 +/- 3 mu mol/100 cm(3)/min, respectively. The average oxygen extract ion fraction was 0.46 +/- 0.09 and the oxygen-glucose ratio was 6.1 +/ - 0.8. The findings indicate that the pig is suitable for PET studies of cerebral blood flow, cerebral oxygen consumption and glucose metabo lism. (C) 1997 Elsevier Science B.V.