Epidermal growth factor regulates Ca2+ uptake in primary cultured renal proximal tubule cells: involvement of cAMP, PKC and cPLA2.
Epidermal growth factor (EGF) is known to play an important role in modulating renal transport functions. Thus, we investigated the effect of EGF on Ca(2+) uptake and its related signals in the primary cultured rabbit renal proximal tubule cells. EGF (50 ng/ml, 1 h) stimulated Ca(2+) uptake. Its effect was blocked by AG 1478 (an EGF receptor antagonist), genistein or herbimycin A (tyrosine kinase inhibitors). EGF increased intracellular cAMP level and SQ 22536 (an adenylate cyclase inhibitor), Rp-cAMP (a cAMP analogue), or PKI (a protein kinase A inhibitor) blocked the EGF-induced stimulation of Ca(2+) uptake. EGF-induced stimulation of Ca(2+) uptake was also blocked by neomycin or U-73122 (phospholipase C inhibitors), staurosporine, H-7, or bisindolylmaleimide I (protein kinase C inhibitors), nifedipine or methoxyverapamil (L-type Ca(2+) channel blockers). It increased IPs formation by 167 +/- 5% compare to control within 90 s. On the other hand, EGF increased [(3)H]-arachidonic acid release, which was significantly blocked by PKC inhibitors. In addition, PGE(2), one of cyclooxygenase metabolites, and 5,6-EET, one of cytochrome P-450 metabolites, increased Ca(2+) uptake. These results suggest that cAMP, PLC/PKC, and PLA(2) are involved in EGF-induced stimulation of Ca(2+) uptake.
Han
Ho Jae
HJ
Department of Veterinary Physiology, College of Veterinary Medicine, Biotechnology Research Institute, Chonnam National University, Gwangju, Korea. hjhan@chonnam.ac.kr
Park
Soo Hyun
SH
Lee
Yun Jung
YJ
D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism; D016227:Benzoquinones; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism*; D002132:Calcium Radioisotopes; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D007687:Kidney Tubules, Proximal / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D047029:Lactams, Macrocyclic; D008297:Male; D010741:Phospholipases A / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011809:Quinones / Q000494:pharmacology; D011817:Rabbits; D017828:Rifabutin / Q000031:analogs & derivatives
D016227:Benzoquinones; D002132:Calcium Radioisotopes; D004791:Enzyme Inhibitors; D047029:Lactams, Macrocyclic; D011809:Quinones; D017828:Rifabutin; D016718:Arachidonic Acid; D004815:Epidermal Growth Factor; C020754:herbimycin; D000242:Cyclic AMP; D011493:Protein Kinase C; D010741:Phospholipases A; D002118:Calcium