Cardiovascular and endocrine responses to feeding in the young calf.

Abstract

There was a substantial increase in both heart rate and mean aortic blood pressure during feeding in these animals. This occurred within the 1st few seconds and persisted throughout the period of ingestion. The concentrations of glucose, insulin and gastrin in arterial plasma rose abruptly during, or immediately after, feeding and elevated values persisted for at least 2 h. A transient increase in glucagon concentration was also observed. Feeding appeared to produce no immediate rise in enteroglucagon concentration. The adrenal output of glucocorticoids rose transiently in response to feeding but that of catecholamines was unaffected. Cardiovascular responses to feeding were also examined in other species. In unweaned kids the changes were essentially similar to those observed in the calf but were less pronounced. In lambs a persistent hypertension occurred which was associated with a brief initial tachycardia. In adult dogs ingestion of solid food also caused tachycardia and although the aortic blood pressure rose for a short period at the beginning of feeding, hypotension developed thereafter. The possibility that the cardiovascular and endocrine responses, which occurred during or immediately after feeding, were mediated by the autonomic nervous system was discussed.