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Estradiol‐17β‐BSA stimulates Ca 2+ uptake through nongenomic pathways in primary rabbit kidney proximal tubule cells: Involvement of cAMP and PKC
Author(s) -
Han HoJae,
Lee YeuneHee,
Park SooHyun
Publication year - 2000
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/(sici)1097-4652(200004)183:1<37::aid-jcp5>3.0.co;2-n
Subject(s) - protein kinase c , endocrinology , medicine , cycloheximide , stimulation , antiporter , amiloride , chemistry , channel blocker , calphostin c , biology , calcium , signal transduction , biochemistry , sodium , protein biosynthesis , organic chemistry , membrane
The effect of estradiol‐17β‐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 × 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. J. Cell. Physiol. 183:37–44, 2000. © 2000 Wiley‐Liss, Inc.