Regulation of natriuretic peptide (urodilatin) release in a human kidney cell line.
BACKGROUND
To identify the molecular mechanisms underlying the release of a renal natriuretic peptide (NP) we selected a human kidney cell line (HEK 293) that displays several characteristics of distal tubular cells.


METHODS
Cells were exposed to different extracellular and intracellular stimuli, and the effect on NP release was measured with a specific urodilatin radioimmunoassay, as well as with an atrial NP (ANP) radioimmunoassay.


RESULTS
In the absence of stimuli, HEK 293 cells showed a basal release of urodilatin immunoreactivity and ANP immunoreactivity. Raising the osmolality of the secretion medium with sodium chloride and various other osmolytes rapidly increased cellular NP secretion. Elevation of intracellular cAMP levels by forskolin plus 3-isobutyl-1-methylxanthine and administration of phorbol-12-myristate-13-acetate together with the calcium-ionophore A23187 also resulted in respective increases in the amount of secreted peptide. HEK 293 cells exhibit the endogenous expression of both particulate and soluble guanylyl cyclases. In the presence of 8-Br-cGMP, cell cultures showed the enhanced secretion of an ANP immunoreactive peptide only, indicating that guanylyl cyclase activation provoked the secretion of ANP immunoreactivity but not of urodilatin immunoreactivity.


CONCLUSIONS
The human embryonic kidney cell line HEK 293 represents a renal cellular model system in which we have identified a rapid and regulated release of NPs in response to the osmotic effect of increased extracellular sodium chloride and various intracellular stimuli.
Lenz
W
W
Institut für Luft- und Raumfahrtmedizin des Deutschen Zentrums für Luft- und Raumfahrt (DLR), Cologne, Germany.
Herten
M
M
Gerzer
R
R
Drummer
C
C
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D009320:Atrial Natriuretic Factor / Q000378:metabolism*; D000001:Calcimycin / Q000494:pharmacology; D002460:Cell Line; D005576:Colforsin / Q000494:pharmacology; D003470:Culture Media; D000242:Cyclic AMP / Q000378:metabolism; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000096:biosynthesis / Q000494:pharmacology; D006162:Guanylate Cyclase / Q000378:metabolism; D006801:Humans; D007424:Intracellular Fluid / Q000187:drug effects / Q000378:metabolism; D007668:Kidney / Q000187:drug effects / Q000378:metabolism*; D009994:Osmolar Concentration; D010446:Peptide Fragments / Q000378:metabolism*; D011863:Radioimmunoassay; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D003470:Culture Media; D010446:Peptide Fragments; D005576:Colforsin; C016276:8-bromocyclic GMP; D000001:Calcimycin; C056452:Ularitide; D009320:Atrial Natriuretic Factor; D000242:Cyclic AMP; D006162:Guanylate Cyclase; D006152:Cyclic GMP; D013755:Tetradecanoylphorbol Acetate; D015056:1-Methyl-3-isobutylxanthine