title: Sodium-lithium countertransport and blood pressure in healthy blood donors.
abstract: Studies finding an increased maximal rate of Na-Li countertransport in red blood cells from persons with essential hypertension and their normotensive offspring have raised the possibility that Na-Li countertransport may serve as a marker for the genetic predisposition to hypertension. We studied Na-Li countertransport in 238 randomly selected blood donors representative of the population of Rochester, Minnesota. The mean value (+/- SD) for Na-Li countertransport in units of mmoles of lithium efflux per liter of red blood cells per hour was 0.29 +/- 0.12. The distribution of Na-Li countertransport values among the donors was continuous. An analysis for multimodality, however, detected significant evidence of bimodality with 72% of the population predicted to belong to the lower mode with a mean of 0.24 mmol/L red blood cells per hour and 28% of the population to belong to the upper mode with a mean of 0.42 mmol/L red blood cells per hour. There was a positive association between Na-Li countertransport and blood pressure; after adjustment for weight and age, Na-Li countertransport predicted approximately 3% of the variation in blood pressure. Persons belonging to the upper mode of the Na-Li countertransport distribution may be at increased risk of acquiring elevated blood pressure as they age.
mesh_terms: D000328:Adult; D001782:Blood Donors; D001794:Blood Pressure; D004912:Erythrocytes / Q000378:metabolism; D005260:Female; D006801:Humans; D006973:Hypertension / Q000235:genetics*; D008094:Lithium / Q000097:blood*; D008297:Male; D008875:Middle Aged; D012964:Sodium / Q000097:blood*
chemical_list: D008094:Lithium; D012964:Sodium