Measurement of erythrocyte Na,K-ATPase activity in normal pregnant women.
To investigate the peripheral metabolic status during normal pregnancy, we measured the number of erythrocyte Na,K-ATPase units as well as the cation transport activity of the pump from 32 normal pregnant women and 12 normal controls. The number of pump units determined by maximal ouabain binding to erythrocyte in normal pregnancy was significantly higher than that in normal controls (mean +/- SEM: 0.52 +/- 0.03 vs. 0.39 +/- 0.04 pmol/10(9)RBC, P < 0.05). The total cation transport activity of the pump measured by 86Rb uptake also significantly increased during pregnancy (98.9 +/- 6.4 vs. 73.1 +/- 5.4 nmol/10(9) RBC, P < 0.01). However, the mean cation transport activity per pump unit, which was presumed to be an indicator of the peripheral metabolic status, was unchanged in any of three trimesters when compared with that in normal controls. Serum FT4 levels measured by two different methods were significantly lower in the third trimester than in the first trimester (P < 0.01). In conclusion, erythrocyte Na, K-ATPase activity per pump unit is normal in pregnant women, suggesting that the peripheral metabolic status in pregnancy seems to be normal. Increases in both the number and function of the pump may be influenced by factors other than thyroid function.
Yoshimura
M
M
Second Department of Internal Medicine, Kansai Medical University, Osaka, Japan.
Nishikawa
M
M
Ogasawara
H
H
Horimoto
M
M
Yoshikawa
N
N
Sawaragi
I
I
Inada
M
M
D000328:Adult; D006063:Chorionic Gonadotropin / Q000378:metabolism; D004910:Erythrocyte Membrane / Q000201:enzymology; D004912:Erythrocytes / Q000201:enzymology*; D005260:Female; D006801:Humans; D011247:Pregnancy / Q000097:blood*; D012016:Reference Values; D000254:Sodium-Potassium-Exchanging ATPase / Q000097:blood*; D013972:Thyrotropin / Q000097:blood
D006063:Chorionic Gonadotropin; D013972:Thyrotropin; D000254:Sodium-Potassium-Exchanging ATPase