da Rosa Luciana Abreu, Escott Gustavo Monteiro, Cavalari Fernanda Carvalho, Schneider Clara Maria Müller, de Fraga Luciano Stürmer, Loss Eloísa da Silveira
Laboratório de Endocrinologia Experimental e Eletrofisiologia, Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Brazil.
Laboratório de Endocrinologia Experimental e Eletrofisiologia, Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Brazil.
Steroids. 2015 Jan;93:32-8. doi: 10.1016/j.steroids.2014.10.007. Epub 2014 Nov 20.
The intratesticular testosterone concentration is high during the early postnatal period although the intracellular androgen receptor expression (iAR) is still absent in Sertoli cells (SCs). This study aimed to evaluate the non-classical effects of testosterone and epitestosterone on calcium uptake and the electrophysiological effects of testosterone (1μM) on SCs from rats on postnatal day (pnd) 3 and 4 with lack of expression of the iAR. In addition, crosstalk on the electrophysiological effects of testosterone and epitestosterone with follicle stimulating hormone (FSH) in SCs from 15-day-old rats was evaluated. The isotope (45)Ca(2+) was utilized to evaluate the effects of testosterone and epitestosterone in calcium uptake. The membrane potential of SCs was recorded using a standard single microelectrode technique. No immunoreaction concerning the iAR was observed in SCs on pnd 3 and 4. At this age, both testosterone and epitestosterone increased the (45)Ca(2+) uptake. Testosterone promoted membrane potential depolarization of SCs on pnd 4. FSH application followed by testosterone and epitestosterone reduced the depolarization of the two hormones. Application of epitestosterone 5 min after FSH resulted in a delay of epitestosterone-promoted depolarization. The cell resistance was also reduced. Thus, in SCs from neonatal Wistar rats, both testosterone and epitestosterone act through a non-classical mechanism stimulating calcium uptake in whole testes, and testosterone produces a depolarizing effect on SC membranes. Testosterone and epitestosterone stimulates non-classical actions via a membrane mechanism, which is independent of iAR. FSH and testosterone/epitestosterone affect each other's electrophysiological responses suggesting crosstalk between the intracellular signaling pathways.
尽管生后早期睾丸内睾酮浓度较高，但支持细胞（SCs）中仍不存在细胞内雄激素受体表达（iAR）。本研究旨在评估睾酮和表睾酮对钙摄取的非经典作用，以及睾酮（1μM）对出生后第3天和第4天缺乏iAR表达的大鼠SCs的电生理作用。此外，还评估了睾酮和表睾酮与促卵泡激素（FSH）对15日龄大鼠SCs电生理作用的相互影响。利用同位素（45）Ca（2+）评估睾酮和表睾酮对钙摄取的影响。使用标准单微电极技术记录SCs的膜电位。在出生后第3天和第4天的SCs中未观察到与iAR相关的免疫反应。在这个年龄段，睾酮和表睾酮均增加了（45）Ca（2+）摄取。睾酮促进了出生后第4天SCs的膜电位去极化。FSH作用后再给予睾酮和表睾酮可降低这两种激素的去极化作用。FSH作用5分钟后给予表睾酮导致表睾酮促进的去极化延迟。细胞电阻也降低。因此，在新生Wistar大鼠的SCs中，睾酮和表睾酮均通过非经典机制刺激整个睾丸的钙摄取，且睾酮对SCs膜产生去极化作用。睾酮和表睾酮通过一种独立于iAR的膜机制刺激非经典作用。FSH与睾酮/表睾酮相互影响对方的电生理反应，提示细胞内信号通路之间存在相互作用。
