POSITIVE INOTROPIC ACTION OF INSULIN ON PIGLET HEART

Google Scholar
  • 1 January 1975
    • journal article
    • research article
    • Vol. 48  (5) , 353-360
Abstract
Piglets of 1 day-12 wk of age were prepared for evaluation of myocardial contractility by measurement of left ventricular dP/dt max [maximum change of pressure with time] under constant hemodynamic conditions. Practolol (1 mg/kg) was given to each animal to provide .beta. adrenergic blockade. In 12 piglets given crystallin insulin (40 units), arterial glucose fell from 102 to 22 mg% after 75 min. This was accompanied by an increase of dP/dt max to 138% of initial values within 30 min. The positive inotropic effect persisted for the duration of the study. Eight control animals and 2 piglets given glucagon (50 .mu.g/kg) showed no significant change. After the 75-min study period, each animal was made hypoxic by ventilation with N2. The time of onset and severity of hypoxic left heart failure in piglets given insulin did not differ from control animals. Insulin augments myocardial contractility in the piglet and this property is independent of adrenergic mechanisms or glucagon contamination. Insulin administration apparently does not diminish cardiac depression engendered by acute hypoxia.