Blood flow and autoregulation in rat pituitary gland

The authors describe an experimental model that allows dynamic studies of blood flow in the pituitary gland. Twenty-eight male Wistar rats were anesthetized and the pituitary gland was exposed using a parapharyngeal approach. Teflon-coated platinum wire electrodes were placed in the adenohypophysis near the midline and laterally as well as in the parietal cortex and the white matter. Blood flows were measured by the hydrogen clearance method. Baseline values were as follows: 89.9 +/- 22 ml/100 gm/min in the medial adenohypophysis, 55.9 +/- 8 ml/100 gm/min in the lateral adenohypophysis, 59.2 +/- 14 ml/100 gm/min in the parietal cortex, and 28.1 +/- 8.9 ml/100 gm/min in the white matter. Effective autoregulation was demonstrated by altering the blood pressure with metaraminol infusion or blood withdrawal. The range of autoregulation was wider in the adenohypophysis than in the cerebral cortex.