Angiotensin production and metabolism in sheep

1. The arterial and central venous concentrations of angiotensin I, II and III have been determined in Na replete and Na depleted conscious sheep. 2. During Na deficiency the arterio-venous ratios of angiotensin I, II and III were 0.48, 1.30 and 1.52 respectively. 3. During infusion of angiotensin II or III, the arterio-venous ratios were 2.1 for angiotensin II and 2.2 for angiotensin III. 4. The blood clearance rate of angiotensin II and III in Na depleted sheep were 135 and 140 l/h respectively; values similar to those found in Na replete animals. 5. The angiotensin III concentration in arterial blood is 42% of that found for angiotensin II. 6. A steady state model of angiotensin production and metabolism has been constructed and shows that 55% of arterial angiotensin II and 40% of angiotensin III are derived in the peripheral vascular bed. These are minimal estimates.