EFFECT OF HYPERAMMONEMIA ON BLOOD-GLUCOSE AND PLASMA-INSULIN LEVELS IN SHEEP

The effects of continuous intravenous infusions (6 h) of ammonium chloride (5·6; 11·2; and 16·8 µmol.kg‐1) on plasma glucose and immunoreactive insulin (I.R.I.) levels were studied in three adult sheep. Infusions of 5·6 and 11·2 µmol.kg‐1.min elevated ammonia levels in circulating blood from 100 to 150 and 300, µg. 100ml‐1, respectively, but showed no appreciable effect on plasma glucose and I.R.I. concentrations. Infusion of 16·8 µmol kg‐1.min‐1 resulted in a blood ammonia concentration of about 400 µg.100ml‐1 after six hours of infusion. Blood ammonia returned to normal 1 to 2 hours after the end of infusion. Plasma glucose concentration tended to increase slightly from 65 to 75 mg. 100ml‐1 when 16·8 µmol of NH4Cl were infused kg‐1.min‐1 and remained at the elevated level at least for two additional hours when ammonia infusions were stopped. Plasma I.R.I. tended to decrease from 48 to 38 µU.ml‐1 during the time of the NH4Cl infusion and increased continually to 82µU.ml‐1 when NH4Cl infusions were stopped. It is concluded from the time courses of plasma glucose and plasma I.R.I. that the effect of ammonia infusion on these parameters cannot entirely be explained by a regulatory release of adrenaline. © 1979 The Physiological Society