Calcium and magnesium ATPase activities in women with varying BMIs.
OBJECTIVE
Intracellular calcium (Ca) is increased in obese humans, and magnesium (Mg)-ATPase activity is increased in monosodium glutamate-induced obese rats. The aims of this study were to test the hypotheses that Ca-ATPase activity is negatively correlated with BMI, and that Mg-ATPase activity is positively correlated with BMI and Ca-ATPase activity in obese women.


METHODS
Thirty healthy adult women, with BMIs of 20 to 40, donated a single sample of whole blood and were interviewed as to medical history and family history of obesity. Erythrocyte membranes were isolated and assayed for Ca-ATPase and Mg-ATPase. Weight and height were self-reported. Regression analysis was used to determine relationship between BMI and enzyme activity. Family history of obesity served as a covariant.


RESULTS
Ca-ATPase was negatively correlated with increasing BMI (r = - 0.38, p = 0.02). The relationship between BMI and Ca-ATPase remained valid after controlling for family history of obesity (r = -0.36, p = 0.03). There was a positive correlation between Mg-ATPase activity and Ca-ATPase (r = 0.42, p = 0.024), and this relationship remained valid after controlling for BMI and family history of obesity (r = 0.41, p = 0.03).


CONCLUSIONS
Ca-ATPase activity decreases as BMI increases. Decreased ATPase activity may contribute to increased intracellular calcium, previously reported in obese persons. Further studies are needed to determine whether a drop in Ca-ATPase activity can serve as a marker for the development of obesity.
Nasser
Jennifer A
JA
Department of Food Science, Rutgers University, New Brunswick, NJ, USA. jnasser@att.net
Hashim
Sami A
SA
Lachance
Paul A
PA
D000328:Adult; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D017301:Ca(2+) Mg(2+)-ATPase / Q000097:blood*; D002118:Calcium / Q000097:blood; D000252:Calcium-Transporting ATPases / Q000097:blood*; D004910:Erythrocyte Membrane / Q000201:enzymology; D005260:Female; D006801:Humans; D008875:Middle Aged; D009765:Obesity / Q000201:enzymology; D012044:Regression Analysis
D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases; D002118:Calcium