CONTROL OF PLASMA-VOLUME EXPANSION IN THE PREGNANT FOOD RESTRICTED RAT

The aim of this study was to define the role of the renin-angiotensin-aldosterone system (RAAS) in reduced plasma volume expansion associated with food restriction imposed during early pregnancy in the rat. Ad libitum fed (C) and food restricted (FR) pregnant and non-pregnant rats and FR sodium-supplemented pregnant rats (FRS) were compared. Total plasma volume at term was higher in C group than in either FR and FRS groups. When values were expressed per 100 g of body wt these inter-group differences disappeared. Plasma renin activity was elevated in pregnant C and FR rats, but values in FRS were within the range of nonpregnant groups. Plasma aldosterone levels were elevated in all pregnant groups. Highest values of this hormone were observed in FR animals. Urinary sodium excretion was five-fold higher in FRS rats than in either C or FR. Non-pregnant C rats excreted twice the amount of sodium of pregnant C while pregnant and non-pregnant FR had a similar urinary sodium excretion. Data indicate that reduced gestational plasma volume expansion associated with food restriction occurs despite an adequate RAAS response. © 1990 Pergamon Press plc.