Fig 1.

A comparative depiction of average urinary excretion rates of cations (Na, K, Ca and Mg), urine volumes and urine osmolalities in blacks and whites. Na excretion rates are the same in the two race groups, but K, Ca and Mg excretion rates are lower in blacks, consistent with a more active NKCC2 in TAL. Urine (U) volumes are smaller and urine osmolalities are higher in blacks, again consistent with NKCC2 being more active in blacks. Na excretion is the same in the two groups, pointing out similar dietary intakes of Na. Overall, however, blacks may retain more Na, but after coming into balance, excretion begins to equal intake