[Role of Na(+)-glucose cotransport in fluid absorption across alveolar epithelium in isolated rat lungs].
To evaluate the role of Na(+)-glucose cotransport in fluid absorption across alveolar epithelial walls in isolated rat lungs, we measured the inhibitory effects of amiloride (a Na+ channel blocker) and phlorizin (a Na(+)-glucose cotrasport blocker) on the fluid absorption rate in fluid-filled lungs. Amiloride (10(-5)-10(-4) M) reduced alveolar fluid absorption by 30%. This value was similar to that obtained in the presence of 10(-3) M phlorizin. The coefficient of Na(+)-glucose cotransport was estimated to be 2.5. The strong correlation between Na+ escape and fluid absorption (r = 0.907) was not affected by phlorizin. These findings suggest that the impact of Na(+)-glucose cotransport was similar to that of Na+ transport alone, and that glucose molecules transported by Na(+)-glucose cotransport do not play an important role in alveolar fluid absorption across rat alveolar epithelium.
Suzuki
S
S
Department of Thoracic Surgery, Tohoku University.
Noda
M
M
Sugita
M
M
Tanita
T
T
Ono
S
S
Sakuma
T
T
Koike
K
K
Fujimura
S
S
D000042:Absorption; D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D066298:In Vitro Techniques; D008297:Male; D009004:Monosaccharide Transport Proteins / Q000502:physiology*; D010695:Phlorhizin / Q000494:pharmacology; D011650:Pulmonary Alveoli / Q000378:metabolism*; D051381:Rats; D015222:Sodium Channels / Q000187:drug effects
D009004:Monosaccharide Transport Proteins; D015222:Sodium Channels; D000584:Amiloride; D010695:Phlorhizin