The effect of maternal starvation on the metabolic response to cold of the newborn rabbit.

Acute starvation of the pregnant rabbit before delivery leads to lipid mobilization, the circulating concentrations of free fatty acids (FFA) increase, and more fatty acids cross the placenta and are stored as triglyceride in fetal tissues, particularly the liver and adipose tissue. Thus the newborns from these unfed does are born with larger fat stores than normal. In this investigation the responses of newborns of unfed and fed does were compared with respect to aspects of the metabolic responses to birth and subsequent cold exposure. It was found that at 2 hr of age the newborns of unfed does had higher circulating concentrations of FFA and triglycerides. The glucose and glycerol concentrations were similar in the two groups, but after 2 hr of cold exposure the newborns of fed does had much higher blood concentrations of both glucose and glycerol. In both, a large increase in FFA concentration was seen. The newborns of unfed and fed does had similar minimal metabolic rates, but the maximal rate of heat production was greater on average by 15% in the newborns of unfed does over the first 3 days of life. Maternal nutrition immediately before delivery has considerable effect on the circulating concentrations of metabolites and the responses to cold of the newborn.