title: Gastrointestinal and renal excretion of potassium in African-Americans and White Americans.
abstract: OBJECTIVE
  Several studies have confirmed the remarkable observation that cumulative urinary potassium (K(+)) excretion is less in African-Americans than White Americans even when identical amounts of potassium are provided in the diet. This study was designed to examine whether this decrease in urinary potassium could be compensatory to an increase in gastrointestinal excretion of potassium in African-Americans.
  
  
  METHODS
  Twenty-three young, healthy, normotensive participants of both sexes and races were placed on a fixed diet of 100 mEq per day of K(+) and 180 mEq per day of sodium (Na(+)) for 9 days. All urine and stool were collected daily and analyzed for electrolytes. Blood was obtained for determination of electrolytes, blood urea nitrogen (BUN), creatinine, glucose, insulin, renin, and aldosterone at the beginning and at the end of the study period.
  
  
  RESULTS
  Cumulative urinary excretion of K(+) was significantly less in African-Americans (609 ± 31 mEq) compared with White Americans (713 ± 22 mEq, P = 0.015). There was no significant racial difference, however, in the cumulative gastrointestinal excretion of K (105 ± 11 versus 95 ± 9 mEq, P = 0.28) in African-Americans versus White Americans, respectively.
  
  
  CONCLUSIONS
  The racial difference in urinary K(+) handling manifested by decreased excretion of K(+) in African-Americans cannot be attributed to an increase in net gastrointestinal excretion of this cation.
authors.affiliation: Division of Nephrology/Hypertension, Department of Medicine, The Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611-3008, USA. rrosa@northwestern.edu
authors.forename: Robert M
authors.initials: RM
authors.lastname: Rosa
authors.forename: Ernest
authors.initials: E
authors.lastname: De Jesus
authors.forename: Kevin
authors.initials: K
authors.lastname: Sperling
authors.forename: Annie
authors.initials: A
authors.lastname: Suh
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Gmurczyk
authors.forename: Kevin A
authors.initials: KA
authors.lastname: Myrie
authors.forename: Karol
authors.initials: K
authors.lastname: Rosner
authors.forename: Edgar
authors.initials: E
authors.lastname: Lerma
authors.forename: William
authors.initials: W
authors.lastname: Yu
authors.forename: Richard
authors.initials: R
authors.lastname: Breuer
authors.forename: James B
authors.initials: JB
authors.lastname: Young
mesh_terms: D000293:Adolescent; D000328:Adult; D001741:Black or African American; D000450:Aldosterone / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D005260:Female; D041981:Gastrointestinal Tract / Q000378:metabolism*; D006801:Humans; D007328:Insulin / Q000097:blood; D007668:Kidney / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000652:urine*; D012083:Renin / Q000097:blood; D044465:White People; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D007328:Insulin; D000450:Aldosterone; D012083:Renin; D011188:Potassium