Localization, synthetic regulation, and biology of renal atriopeptin-like prohormone.
We recently demonstrated the synthesis and secretion of an atriopeptin (AP)-like prohormone in rat neonatal and adult cortical kidney cell cultures. However, these cultures contained proximal as well as distal tubular epithelial cells; thus characterization of the peptide synthetic cell was not possible. Also, by immunohistochemical techniques, we localized this AP-like prohormone to the distal cortical nephron in adult rat kidney. In this study, we examined further details of the kidney cortical cell type that expresses and secretes this AP-like peptide in adult renal cortical cell cultures, its regulation by adenylate cyclase via adenosine 3',5'-cyclic monophosphate (cAMP) generation, and its ability to stimulate guanylate cyclase. Tubular fragments were derived from cortical tissue of adult Sprague-Dawley rats and separated into four fractions on Percoll density gradient. Cell cultures generated from fraction 3 secreted 5- to 10-fold the amount of this renal peptide compared with fractions 2 and 4. Further cell culture characterization was performed by agonist-stimulated cAMP formation, kallikrein localization, and prostaglandin E2 formation. From these analyses, it was determined that tissue band 3 was enriched for distal cortical connecting tubules. To further evaluate whether mammalian distal nephron synthesizes an AP-like protein, we determined that two immortalized mouse cell lines, derived from either the distal convoluted tubule or cortical collecting tubule, synthesized a radiolabeled AP after being pulsed with [35S]-methionine.(ABSTRACT TRUNCATED AT 250 WORDS)
Department of Pharmacology, Washington University School of Medicine, St. Louis 63110.
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D
Ritter
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J
Chao
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Needleman
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Tetens
J E
JE
Greenwald
D000818:Animals; D000831:Animals, Newborn; D009320:Atrial Natriuretic Factor / Q000378:metabolism / Q000502:physiology*; D002478:Cells, Cultured; D006162:Guanylate Cyclase / Q000378:metabolism; D006325:Heart Atria; D007610:Kallikreins / Q000378:metabolism; D007668:Kidney / Q000166:cytology / Q000378:metabolism*; D007679:Kidney Medulla; D007685:Kidney Tubules, Collecting / Q000201:enzymology; D007686:Kidney Tubules, Distal / Q000378:metabolism; D009206:Myocardium / Q000201:enzymology; D011498:Protein Precursors / Q000378:metabolism / Q000502:physiology*; D014018:Tissue Distribution
D011498:Protein Precursors; D009320:Atrial Natriuretic Factor; D007610:Kallikreins; D006162:Guanylate Cyclase