Effect of acute hyperglycemia on erythrocyte membrane ion transport in offspring of hypertensive parents.
OBJECTIVE
Patients with essential hypertension exhibit several red blood cell (RBC) ion transport abnormalities, insulin resistance (IR) and increased risk of developing type 2 diabetes. The aims of this study were to assess RBC ion transport activities under basal conditions and to test the in vivo effect of acute hyperglycemia on RBC ion transport in the offspring of hypertensive parents (OHP) and healthy controls (C).


METHODS
Activities of Na+-K+ pump, Na+-K+ cotransport, Na+-Li+ countertransport (SLC) and Na+, Rb+ and Li+ leaks were measured before and after a 5-h hyperglycemic (12 mmol/l) clamp (HGC) and compared to values found under euglycemic isovolumic conditions in OHP (n = 12) and C (n = 14). Insulin action was calculated as insulin sensitivity index (M/I) during HGC.


RESULTS
The offspring of hypertensive parents were characterized by lower M/I (0.07 +/- 0.03 versus 0.12 +/- 0.07 mg/kg per min per microU per ml; P < 0.05) and elevated SLC (0.080 +/- 0.004 versus 0.068 +/- 0.003 mmol/h per litre; P < 0.05), as well as by higher Li+ (0.106 +/- 0.004 versus 0.093 +/- 0.003 mmol/h per litre; P < 0.05) and Rb+ leaks (0.160 +/- 0.014 versus 0.120 +/- 0.007 mmol/h per litre; P < 0.05) compared to controls. Acute hyperglycemia did not cause significant changes in any investigated RBC ion transport parameters.


CONCLUSIONS
The offspring of hypertensive parents displayed higher insulin resistance, enhanced activity of SLC and formerly undocumented augmented Li+ and Rb+ leaks. Acute hyperglycemia did not modify any RBC ion transport activities in either offspring of hypertensive parents or controls.
Suchánková
Gabriela
G
Diabetes Center, Institute for Clinical and Experimental Medicine, Czech Academy of Sciences, Prague, Czech Republic. SuchanG@pbrc.edu
Vlasáková
Zuzana
Z
Zicha
Josef
J
Vokurková
Martina
M
Dobesová
Zdena
Z
Pelikánová
Terezie
T
D000208:Acute Disease; D000328:Adult; D004910:Erythrocyte Membrane / Q000378:metabolism*; D015309:Glucose Clamp Technique; D006801:Humans; D006943:Hyperglycemia / Q000378:metabolism*; D006973:Hypertension / Q000378:metabolism*; D008094:Lithium / Q000493:pharmacokinetics; D008297:Male; D010290:Parents; D011188:Potassium / Q000378:metabolism; D011972:Receptor, Insulin; D012413:Rubidium / Q000493:pharmacokinetics; D012964:Sodium / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
D008094:Lithium; D012964:Sodium; D011972:Receptor, Insulin; D000254:Sodium-Potassium-Exchanging ATPase; D012413:Rubidium; D011188:Potassium