title: Estradiol-17beta-BSA stimulates Ca(2+) uptake through nongenomic pathways in primary rabbit kidney proximal tubule cells: involvement of cAMP and PKC.
abstract: The effect of estradiol-17beta-BSA (E(2)-BSA) on Ca(2+) uptake and its related signal pathways were examined in the primary cultured rabbit kidney proximal tubule cells. E(2)-BSA (10(-9) M) significantly stimulated Ca(2+) uptake from 2 h by 13% and at 8 h by 35% as compared to control, respectively. This stimulatory effect of E(2)-BSA was not inhibited by tamoxifen (10(-8) M, an intracellular estrogen receptor antagonist), actinomycin D (10(-7) M, a transcription inhibitor), and cycloheximide (4 x 10(-5) M, a protein synthesis inhibitor). However, E(2)-BSA-induced stimulation of Ca(2+) uptake was blocked by methoxyverapamil (10(-6) M, an L-type calcium channel blocker) and 5-(N-ethyl-N-isopropyl)-amiloride (10(-5) M, a Na(+)/H(+) antiporter blocker). These results suggest that E(2)-BSA stimulates Ca(2+) uptake through nongenomic pathways. Thus, we investigated which signal pathways were related to E(2)-BSA-induced stimulation of Ca(2+) uptake. 8-Br-cAMP (10(-6) M) alone increased Ca(2+) uptake by 22% compared to control. When E(2)-BSA combined with 8-Br-cAMP, Ca(2+) uptake was not significantly stimulated compared to E(2)-BSA. SQ 22536 (10(-6) M, an adenylate cyclase inhibitor) and myristoylated protein kinase A inhibitor amide 14-22 (10(-6) M, a protein kinase A inhibitor) blocked E(2)-BSA-induced stimulation of Ca(2+) uptake and E(2)-BSA also increased cAMP generation by 26% of that of control. In addition, TPA (0.02 ng/ml, an artificial PKC promoter) stimulated the Ca(2+) uptake by 14%, and the cotreatment of TPA and E(2)-BSA did not significantly stimulate Ca(2+) uptake compared to E(2)-BSA. E(2)-BSA-induced stimulation of Ca(2+) uptake was blocked by U 73122 (10(-6) M, a phospholipase C inhibitor) or bisindolylmaleimide I (10(-6) M, a protein kinase C inhibitor). Indeed, E(2)-BSA stimulated PKC activity by 26%. In conclusion, E(2)-BSA (10(-9) M) stimulated Ca(2+) uptake by nongenomic action, which is mediated by cAMP and PKC pathways.
authors.affiliation: Department of Veterinary Physiology, College of Veterinary Medicine, Hormone Research Center, Chonnam National University, Kwangju, Korea. hjhan@chonnam.chonnam.ac.kr
authors.forename: H J
authors.initials: HJ
authors.lastname: Han
authors.forename: Y H
authors.initials: YH
authors.lastname: Lee
authors.forename: S H
authors.initials: SH
authors.lastname: Park
mesh_terms: D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D000584:Amiloride / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D003513:Cycloheximide / Q000494:pharmacology; D003609:Dactinomycin / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004958:Estradiol / Q000494:pharmacology*; D004963:Estrenes / Q000494:pharmacology; D004966:Estrogens, Conjugated (USP) / Q000494:pharmacology; D005711:Gallopamil / Q000494:pharmacology; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D007700:Kinetics; D008297:Male; D010281:Parathyroid Hormone / Q000494:pharmacology; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism; D011760:Pyrrolidinones / Q000494:pharmacology; D011817:Rabbits; D012710:Serum Albumin, Bovine / Q000494:pharmacology*; D013629:Tamoxifen / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D000889:Anti-Arrhythmia Agents; D004791:Enzyme Inhibitors; D004963:Estrenes; D004966:Estrogens, Conjugated (USP); D010281:Parathyroid Hormone; D010726:Phosphodiesterase Inhibitors; D011760:Pyrrolidinones; C043090:estradiol-bovine serum albumin; D013629:Tamoxifen; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; C017759:9-(tetrahydro-2-furyl)-adenine; D003609:Dactinomycin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D012710:Serum Albumin, Bovine; D005711:Gallopamil; D004958:Estradiol; D000584:Amiloride; D003513:Cycloheximide; D000242:Cyclic AMP; D011493:Protein Kinase C; D000225:Adenine; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium; C039614:ethylisopropylamiloride