Cerebrovascular integrity in protein-deprived rats

Protein-deprivation does not increase the permeability of the blood-brain barrier in rats aged 3.5--12 months. PA, the product of cerebrovascular permeability (P) to 14C-sucrose and of cerebral capillary surface area (A), is very low in mature rats that have been maintained either on an 8% or 25% casein diet, and equals about 8 X 10(-6) sec-1 in both groups. There is a tendency for the calculated distribution volume of 14C-sucrose within the brain to decline in protein-deprived rats. Conscious, partially immobilized, protein-deprived rats have the same mean blood pressure, heart rate, arterial plasma pH and adreno-sympathetic response to stress (as measured by plasma norepinephrine and epinephrine concentrations) as do normally fed animals.