Amino acids are compatible osmolytes for volume recovery after hypertonic shrinkage in vascular endothelial cells.
The response to chronic hypertonic stress has been studied in human endothelial cells derived from saphenous veins. In complete growth medium the full recovery of cell volume requires several hours and is neither associated with an increase in cell K+ nor hindered by bumetanide but depends on an increased intracellular pool of amino acids. The highest increase is exhibited by neutral amino acid substrates of transport system A, such as glutamine and proline, and by the anionic amino acid glutamate. Transport system A is markedly stimulated on hypertonic stress, with an increase in activity roughly proportional to the extent and the duration of the osmotic shrinkage. Cycloheximide prevents the increase in transport activity of system A and the recovery of cell volume. It is concluded that human endothelial cells counteract hypertonic stress through the stimulation of transport system A and the consequent expansion of the intracellular amino acid pool.
Dall'Asta
V
V
Istituto di Patologia Generale, Università degli Studi di Parma, 43100 Parma, Italy.
Bussolati
O
O
Sala
R
R
Parolari
A
A
Alamanni
F
F
Biglioli
P
P
Gazzola
G C
GC
D000596:Amino Acids / Q000378:metabolism*; D001692:Biological Transport / Q000187:drug effects; D002034:Bumetanide / Q000494:pharmacology; D048429:Cell Size; D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D005973:Glutamine / Q000378:metabolism; D006706:Homeostasis; D006801:Humans; D006982:Hypertonic Solutions; D007700:Kinetics; D011188:Potassium / Q000378:metabolism; D012501:Saphenous Vein; D012964:Sodium / Q000378:metabolism; D013997:Time Factors
D000596:Amino Acids; D006982:Hypertonic Solutions; D005973:Glutamine; D002034:Bumetanide; D003513:Cycloheximide; D012964:Sodium; D011188:Potassium