Studies on the carbohydrate metabolism of sheep. IX. Metabolic effects of glucose and glycerol in undernourished pregnant ewes and in ewes with pregnancy toxaemia

Abstract

The rate of utilization of injected glucose by fasted pregnant ewes or ewes with pregnancy toxaemia is much more rapid than by fasted non-pregnant ewes. An apparent relation between the rate of utilization and the number of fetuses was observed; much of the injected glucose may be removed by the foetus(es).

The pronounced rise in blood glucose recorded after lambing and when foetuses apparently died in utero is also considered to reflect sudden cessation of high foetal demands for glucose.

Intravenous administration of glucose consistently reduced blood ketones in ewes with a moderate hyperketonaemia and showing no clinical signs of pregnancy toxaemia. Ketones declined in ewes fasted 1–3 days as soon as blood glucose began to increase at lambing. In ewes with pregnancy toxaemia there was usually no reduction of ketones in response to injected glucose; blood acetic acid levels, if previously high, did not decline; blood citric acid failed to increase.

Glycerol given per os to ewes with pregnancy toxaemia always caused a rapid decline in blood ketones, and in acetic acid if the latter was previously high; a, pronounced increase in blood citric acid always occurred. These changes were recorded although no clinical improvement was observed.

Glucose administered parenterally over 48 hr appeared to be less efficiently utilized by ewes with pregnancy toxaemia than by fasted pregnant ewes showing no clinical signs. Blood ketones declined to normal levels within 48 hr; in probable contrast to fasted ewes, this is considered to have occurred in the ewes with pregnancy toxaemia only because hyperglycaemia was continuously maintained.

These results are considered to support the hypothesis that gluoose metabolism is depressed in ewes with pregnancy toxaemia and that the metabolic abnormalities are consistent with those characteristic of a diabetic-like syndrome.