AREGU February 47/2

Ely, Daniel, Michael Herman, Lawrence Ely, Linda Barrett, and Amy Milsted. Sodium intake is increased by social stress and the Y chromosome and reduced by clonidine. Am. J. Physiol. Regulatory Integrative Comp. Physiol. 278: R407–R412, 2000.—The objectives were to determine 1) if female rats have higher Na intake than males and if social stress increases Na intake, 2) if the sympathetic nervous system (SNS) mediates the stress effects and the gender effect, and 3) if the Y chromosome (Yc) from a hypertensive father increases Na intake. Four rat strains (n 5 10/group) of both sexes were used: 1) Wistar Kyoto normotensive (WKY), 2) an F16 backcross with a Yc from a hypertensive father (SHR/y), 3) spontaneously hypertensive rat (SHR), and 4) an F16 backcross with a Yc from a normotensive father (SHR/a). Females showed greater baseline Na intake than males (hypertensive strains), intruder stress increased Na intake, and clonidine decreased Na intake, but not in WKY or SHR females. SHR/y males had higher baseline Na intake compared with WKY males. In conclusion, the higher Na intake in females during baseline and stress was partially mediated through the SNS in hypertensive strains and the SHR Yc was partially responsible for the increased Na intake in SHR/y and SHR males compared with WKY.