| Full text | |
| Author(s): |
Costa, Roberta Ribeiro
[1]
;
dos Reis, Rosana Inacio
[2]
;
Aguiar, Jose Fernando
[1]
;
Varanda, Wamberto Antonio
[1]
Total Authors: 4
|
| Affiliation: | [1] Univ Sao Paulo, Dept Physiol, Sch Med Ribeirao Preto, BR-14049900 Ribeirao Preto, SP - Brazil
[2] Univ Sao Paulo, Dept Biochem & Immunol, Sch Med Ribeirao Preto, BR-14049900 Ribeirao Preto, SP - Brazil
Total Affiliations: 2
|
| Document type: | Journal article |
| Source: | Cell Calcium; v. 49, n. 3, p. 191-199, MAR 2011. |
| Web of Science Citations: | 11 |
| Abstract | |
LH increases the intracellular Ca(2+) concentration ({[}Ca(2+)](i)) in mice Leydig cells, in a process triggered by calcium influx through T-type Ca(2+) channels. Here we show that LH modulates both T-type Ca(2+) currents and {[}Ca(2+)]; transients through the effects of PKA and PKC. LH increases the peak calcium current (at -20 mV) by 40%. A similar effect is seen with PMA. The effect of LH is completely blocked by the PKA inhibitors H89 and a synthetic inhibitory peptide (IP-20), but only partially by chelerythrine (PKC inhibitor). LH and the blockers induced only minor changes in the voltage dependence of activation, inactivation or deactivation of the currents. Staurosporine (blocker of PKA and PKC) impaired the {[}Ca(2+)](i) changes induced by LH. A similar effect was seen with H89. Although PMA slowly increased the {[}Ca(2+)](i) the subsequent addition of LH still triggered the typical transients in {[}Ca(2+)](i). Chelerythrine also does not avoid the Ca(2+) transients, showing that blockage of PKC is not sufficient to inhibit the LH induced {[}Ca(2+)](i) rise. In summary, these two kinases are not only directly involved in promoting testosterone synthesis but also act on the overall calcium dynamics in Leydig cells, mostly through the activation of PKA by LH. (c) 2011 Elsevier Ltd. All rights reserved. (AU) | |
| FAPESP's process: | 06/50954-7 - Ionic currents and receptors in the physiology of excitable and non-excitable cells |
| Grantee: | Wamberto Antonio Varanda |
| Support Opportunities: | Research Projects - Thematic Grants |