1. Plethysmographic blood flow records made after venous occlusion of the forearm showed a biphasic response which was first vasodilator and then vasoconstrictor. 2. The myogenic nature of the vascoconstrictor phase was confirmed in eight subjects after total autonomic blockade with atropine, propranolol, phentolamine and guanethidine. 3. Forearm venous blood demonstrated a rise in hydrogen ion concentration and a fall in oxygen tension during venous occlusion, which may contribute to the vasodilatation phase.
1. Oral glucose-tolerance tests (100 g) were carried out in six patients with stable well-compensated cryptogenic cirrhosis and in 12 control subjects. 2. In confirmation of previous studies, patients with cirrhosis had high post-glucose serum insulin levels and were glucose intolerant (mean incremental glucose area 954 ± 186 compared with 482 ± 35 mmol 3 h −1 1 −1 in controls; P <0.05) 3. Forearm arteriovenous differences of glucose and forearm blood flows were measured to estimate the proportion of the glucose load metabolized in peripheral tissues. Values in cirrhotic patients and control subjects (5614 ± 1630 compared with 5344 ± 672 μmol of glucose min −1 1 −1 of forearm in 3 h) were similar despite higher glucose levels and sustained high insulin levels in the cirrhotic patients. 4. Peak lactate concentrations after glucose were of similar magnitude in the two groups (0.66 ± 0.12 compared with 0.62 ± 0.75 mmol/l) but in the patients with cirrhosis the peak occurred later and was more sustained. 5. The glucose intolerance of cirrhosis is primarily due to impaired hepatic retention of the glucose load. Insulin resistance in peripheral tissues-5-also be important since the higher insulin concentrations found in cirrhotic patients failed to enhance peripheral glucose uptake.