1伪,25-Dihydroxyvitamin D3 Signaling Pathways on Calcium Uptake in 30-Day-Old Rat Sertoli Cells

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• 作者：Leila Zanatta ; Ariane Zamoner ; Renata Gon莽alves ; Ana Paula Zanatta ; H茅l猫ne Boura茂ma-Lelong ; Serge Carreau ; F谩tima Regina Mena Barreto Silva
• 刊名：Biochemistry
• 出版年：2011
• 出版时间：November 29, 2011
• 年：2011
• 卷：50
• 期：47
• 页码：10284-10292
• 全文大小：427K
• 年卷期：v.50,no.47(November 29, 2011)
• ISSN：1520-4995

文摘

1伪,25-Dihydroxyvitamin D₃ (1,25D₃) is the active metabolite of vitamin D₃ and the major calcium regulatory hormone in tissues. The aim of this work was to investigate the mechanism of action of 1,25D₃ on ⁴⁵Ca²⁺ uptake in Sertoli cells from 30-day-old rats. Results showed that 10^鈥? and 10^鈥?2 M 1,25D₃ increased the rate of ⁴⁵Ca²⁺ uptake 5 and 15 min after hormone exposure and that 1伪,25(OH)₂ lumisterol₃ (JN) produced a similar effect suggesting that 1,25D₃ action occurs via a putative membrane receptor. The involvement of voltage-dependent calcium channels (VDCC) in 1,25D₃ action was evidenced by using nifedipine, while the use of Bapta-AM demonstrated that intracellular calcium was not implicated. Moreover, the incubation with ouabain and digoxin increased the rate of ⁴⁵Ca²⁺ uptake, indicating that the effect of 1,25D₃ may also result from Na⁺/K⁺-ATPase inhibition. In addition, we demonstrated that the mechanism underlying the hormone action involved extracellular signal-regulated kinase (ERK) and protein kinase C (PKC) activation in a phospholipase C-independent way. Furthermore, a local elevation of the level of cAMP, as demonstrated by incubating cells with dibutyryl cAMP or a phosphodiesterase inhibitor, produced an effect similar to that of 1,25D₃, and the inhibition of protein kinase A (PKA) nullified the hormone action. In conclusion, the stimulatory effect of 1,25D₃ on ⁴⁵Ca²⁺ uptake in Sertoli cells occurs via VDCC, as well as PKA, PKC, and ERK activation. These protein kinases seem to act by inhibiting Na⁺/K⁺-ATPase or directly phosphorylating calcium channels. The Na⁺/K⁺-ATPase inhibition may result in Na⁺/Ca²⁺ exchanger activation in reverse mode and consequently induce the uptake of calcium into the cells.