NaCl preference increases during pregnancy and lactation: assessment usingbrief access tests

Pregnancy and lactation are characterized by increases in NaCl intake, as d etermined by long-term consumption tests, which cannot examine the relative contribution of taste and postingestive factors to this phenomenon. Conseq uently, in this study, changes in NaCl preference during pregnancy and lact ation were studied in nulliparous Long-Evans rats using a brief access test (lickometer). In Experiment 1, rats were maintained on a Na+ -adequate die t (0.03% Na+), habituated to lickometer testing, and subsequently assessed during pregnancy and lactation with three 30-s exposures to each of seven t aste solutions: 0.075 M sucrose (base), 0.089 M NaCl in base, 0.158 M NaCl in base, 0.281 M NaCl in base, 0.5 M NaCl in base, 0.158 M NaCl and 0.281 M NaCl. Results indicated higher lick rates to the 0.5 M NaCl in base, 0.158 M NaCl and 0.281 M NaCl solutions during late pregnancy and late lactation (Day 13 and beyond). In Experiment 2, a comparison of two diets differing in sodium content (0.03% a vs. 0.3% Na+) determined that these changes in N aCl preference during pregnancy and lactation were unrelated to dietary sod ium. Thus, the apparent increase in NaCl preference during pregnancy and la ctation, independent of dietary sodium, suggests that this change in prefer ence is not in response to physiological sodium need. (C) 2001 Elsevier Sci ence Inc. All rights reserved.