Hormonal and substrate responses during recovery from hypoglycaemia in man during beta₁‐selective and non‐selective beta‐adrenergic blockade

Abstract

Recovery from acute hypoglycaemia induced by the injection of insulin has been examined in six human subjects under control conditions, under non-selective beta blockade (propranolol) and under selective beta 1 blockade (metoprolol). The normal blood glucose recovery was biphasic with an initial rapid and a slower subsequent phase of recovery. The early recovery mechanism was unaffected by either form of beta blockade, but with propranolol the late phase of recovery was significantly prolonged. Rises in blood lactate and plasma free fatty acids following hypoglycaemia were markedly reduced by propranolol but to a much lesser degree with metoprolol. The counterregulatory hormonal responses of glucagon, cortisol and growth hormone were augmented appropriately for the prolonged hypoglycaemia associated with propranolol. Non-selective beta adrenergic blockade with propranolol is associated with an impairment of the late phase of blood glucose recovery from hypoglycaemia. The possible mechanisms of this impairment are discussed.

Dopamine Versus Epinephrine for Cardiovascular Support in Low Birth Weight Infants: Analysis of Systemic Effects and Neonatal Clinical Outcomes

“…Although blood lactate concentration is used as a marker of anaerobic respiration resulting from cellular hypoxia, a poor correlation between common acid-base parameters and blood lactate concentrations has been found in critically ill neonates. 38 On the other hand, epinephrine infusion produces major effects on carbohydrate metabolism and a rise in plasma lactate mediated by ␤ 2 -adrenoceptor stimulation, 39,40 causing increased skeletal muscle glycogenolysis together with hepatic glycogenolysis and gluconeogenesis. Therefore, the increase in blood glucose concentration, greater demand for insulin therapy despite similar carbohydrate delivery, and increase in blood lactate levels in epinephrine-treated infants found in this study could be also attributed to ␤ 2 -adrenoceptor stimulation.…”

Vessel wall stiffness in type 1 diabetes and the central hemodynamic effects of acute hypoglycemia

“…When the R occurred, the clock timer was reset to zero, and all subsequent measurements were timed relative to this point. This accommodates the variable time interval that occurs among individuals in the development of the R using the insulin infusion technique (9). As soon as R had occurred, the insulin infusion was discontinued, and hypoglycemia was reversed using an intravenous infusion of 20% dextrose to restore normoglycemia.…”

Modest decrements in plasma glucose concentration cause early impairment in cognitive function and later activation of glucose counterregulation in the absence of hypoglycemic symptoms in normal man.

“…2 and 3, Tables I and III). Finally, although lactate may be potentially oxidized by the brain (36) and changes in its plasma concentration might affect cerebral function, it is unlikely that this substrate contributed to the onset of the increased latency of the P300 wave, because plasma lactate concentration does not change in an early phase of hypoglycemia, but increases only in the recovery phase (37).…”