Regional blood flow, capillary permeability, and glucose utilization in two brain tumor models: preliminary observations and pharmacokinetic implications.

Regional quantitative autoradiographic measurements of blood flow, capillary permeability, and glucose utilization were made in rats harboring an intracerebral Walker 256 metastatic tumor or a well-differentiated oligodendroglioma. Distinct differences were observed between the two brain tumor models; regional differences within the metastatic tumor appeared to be partly related to tumor size. The pharmacokinetic implications of these physiological measurements with respect to drug delivery to tumor tissue are discussed. The interrelationship of commonly used parameters to quantitate transport across the blood-brain barrier--permeability coefficient, permeability-surface area product, transfer constant, extraction fraction, equilibrium half-time, and blood flow--and their relevance to effective brain tumor chemotherapy are demonstrated.