Department of Experimental Medicine, Section of Medical Pathophysiology-Sapienza University of Rome, Rome, Italy.
J Sex Med. 2011 Mar;8(3):696-704. doi: 10.1111/j.1743-6109.2010.02152.x. Epub 2010 Dec 22.
Prolonged tadalafil administration in men with erectile dysfunction is associated with increased testosterone (T): estradiol (E(2)) ratio mainly related to reduction of E(2) levels.
To investigate the presence of phosphodiesterase type 5 (PDE5) isoenzyme in primary human visceral adipocytes and whether different PDE5 inhibitors (PDE5i) could directly modulate aromatase (ARO) expression in differentiated human visceral adipocytes in culture.
PDE5 mRNA and protein expression in primary human visceral adipocytes as well as mRNA and protein expression of ARO, with functional activity after selective PDE5 blockade by tadalafil and sildenafil.
Purified primary human visceral pre-adipocytes were differentiated ex vivo and were exposed to tadalafil or sildenafil (1 µM) for different intervals of time (6-12-24-96 hours). ARO mRNA content and expression were measured by Western Blot and quantitative reverse transcription-polymerase chain reaction (qRT-PCR), respectively. T and E(2) in supernatants were measured by ELISA also in the presence of letrozole.
Differentiated adipocytes were found to express detectable levels of PDE5 transcripts. Acute exposure (6 hours) to both PDE5i tadalafil and sildenafil increased ARO mRNA expression by 4.7- and 2.8-fold, respectively (P < 0.001). ARO mRNA and protein levels were increased by the treatment with PDE5i in a time- and dose-dependent manner. Such effect was mimicked by 8-bromo-cGMP but was lost after 24 and 96 hours; differently, the PDE3B specific inhibitor milrinone (1 µM), displayed no effect. Accordingly, long-term exposure (24 and 96 hours) to PDE5i caused a significant increase in E(2) concentrations in the supernatant (1.7 and 2 fold, respectively; P < 0.001), with a parallel reduction of T (15% and 30%, respectively; P < 0.001). Such effect was reversed by the co-incubation with the specific ARO-inhibitor letrozole.
Our results demonstrate that PDE5 is expressed in human visceral adipocytes and that acute exposure to PDE5i selectively stimulates ARO expression, which is related to a specific PDE5 blockade. We speculate that modulation of ARO activity by PDE5i could be one of the mechanisms responsible, at least in part, for the beneficial effects of PDE5i on endothelial and metabolic functions.
在勃起功能障碍患者中延长他达拉非的给药时间与睾酮（T）：雌二醇（E2）比值的增加有关，主要与 E2 水平的降低有关。
研究磷酸二酯酶 5（PDE5）同工酶在原代人内脏脂肪细胞中的存在情况，以及不同的 PDE5 抑制剂（PDE5i）是否可以直接调节培养的分化人内脏脂肪细胞中的芳香酶（ARO）表达。
原代人内脏脂肪细胞中 PDE5 mRNA 和蛋白表达，以及 ARO 的 mRNA 和蛋白表达，在选择性 PDE5 阻断后具有功能活性他达拉非和西地那非。
体外分离纯化原代人内脏前脂肪细胞并进行分化，然后用他达拉非或西地那非（1μM）处理不同时间（6-12-24-96 小时）。Western Blot 和定量逆转录聚合酶链反应（qRT-PCR）分别测量 ARO mRNA 含量和表达。在存在来曲唑的情况下，也通过 ELISA 测量上清液中的 T 和 E2。
分化的脂肪细胞被发现表达可检测水平的 PDE5 转录物。急性暴露（6 小时）于 PDE5i 他达拉非和西地那非分别使 ARO mRNA 表达增加 4.7-和 2.8 倍（P<0.001）。ARO mRNA 和蛋白水平的增加呈时间和剂量依赖性。这种作用可被 8-溴-cGMP 模拟，但在 24 小时和 96 小时后消失；相反，PDE3B 特异性抑制剂米力农（1μM）则没有作用。因此，长期暴露（24 小时和 96 小时）于 PDE5i 导致上清液中 E2 浓度显著增加（分别增加 1.7 和 2 倍；P<0.001），同时 T 浓度降低（分别降低 15%和 30%；P<0.001）。这种作用可被特异性 ARO 抑制剂来曲唑的共孵育所逆转。
我们的结果表明 PDE5 在人内脏脂肪细胞中表达，急性暴露于 PDE5i 选择性刺激 ARO 表达，这与特定的 PDE5 阻断有关。我们推测，PDE5i 对 ARO 活性的调节可能是 PDE5i 对内皮和代谢功能产生有益影响的部分机制之一。
