Atrial natriuretic peptide receptors on the corneal endothelium.
OBJECTIVE
To ascertain whether the corneal endothelium exhibits specific receptors for atrial natriuretic peptide (ANP) and to characterize partially any binding activity.


METHODS
Most experiments employed radioligand-binding techniques to characterize 125I-ANP binding activity. Guanylate cyclase and corneal deturgescence assays were used in an attempt to correlate 125I-ANP binding activity with physiologic processes.


RESULTS
Corneal endothelial cells reversibly bound 125I-ANP with high affinity and exhibited a finite number of 125I-ANP binding sites. These binding sites also bound several ANP fragments but did not show binding affinity for the peptide hormone, vasopressin. Autoradiograms of affinity labeled ANP receptors separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed specifically radiolabeled proteins of several molecular weights in nonreduced samples, but only one major radiolabeled protein of 65 kd when samples were chemically reduced before separation.


CONCLUSIONS
Corneal endothelial cells from several species exhibit specific binding of 125I-ANP. The binding characteristics of these receptors are similar to physiologic ANP receptors identified in other tissues. Several lines of evidence indicate that corneal endothelial ANP receptors are the "clearance" (ANP-C) type.
Walkenbach
R J
RJ
Missouri Lions Eye Research Foundation, Columbia, MO 65201.
Ye
G S
GS
Korenfeld
M S
MS
Boney
F
F
D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000378:metabolism / Q000494:pharmacology; D001667:Binding, Competitive; D002417:Cattle; D002478:Cells, Cultured; D003315:Cornea / Q000166:cytology / Q000502:physiology; D004591:Electrophoresis, Polyacrylamide Gel; D004728:Endothelium, Corneal / Q000187:drug effects / Q000378:metabolism*; D006162:Guanylate Cyclase / Q000378:metabolism; D006801:Humans; D011817:Rabbits; D011869:Radioligand Assay; D017461:Receptors, Atrial Natriuretic Factor / Q000378:metabolism*; D014667:Vasopressins / Q000378:metabolism
D014667:Vasopressins; D009320:Atrial Natriuretic Factor; D006162:Guanylate Cyclase; D017461:Receptors, Atrial Natriuretic Factor