Forearm ischaemia as a test of prostacyclin production: studies in normal subjects and in patients with diabetes mellitus.

Plasma levels of 6-oxo-PGF1 alpha, the hydrolysis product of prostacyclin, were significantly reduced in men with proliferative diabetic retinopathy, compared with normal controls. Male diabetics with background or no retinopathy formed an intermediate group with plasma levels of 6-oxo-PGF1 alpha lower than controls and higher than patients with proliferative retinopathy. Forearm ischaemia increased plasma levels of 6-oxo-PGF1 alpha by 30% in normal subjects. The increase occurred during arterial occlusion and was diminished by pretreatment with aspirin. The increase after ischaemia may reflect increased prostacyclin production. In diabetic patients forearm ischaemia produced an increase in plasma 6-oxo-PGF1 alpha similar to that seen in control subjects.