Tadalafil modulates aromatase activity and androgen receptor expression in a human osteoblastic cell in vitro model.
Level 5 - mechanism / opinion, no new human data
In vitro bench study using a cell line
PubMed 26134065 · doi:10.1007/s40618-015-0344-1
What was done
Human osteoblast-like cells (SAOS-2) were treated in vitro with varying concentrations of tadalafil (10^-8 to 10^-7 M) across multiple time points. The researchers assessed cell viability and measured mRNA and protein expression levels of phosphodiesterase type-5 (PDE5), aromatase, androgen receptor (AR), and estrogen receptor alpha (ERα), as well as testosterone concentrations in culture supernatants.
What was found
Tadalafil exposure increased SAOS-2 cell proliferation. Increasing concentrations of tadalafil (10^-8 to 10^-7 M) decreased PDE5 and aromatase mRNA and protein expression, which was accompanied by increased testosterone levels in the supernatant. Tadalafil also increased total AR mRNA and protein expression and decreased ERα expression, yielding an increased AR/ER ratio. The abstract reports directional changes and concentration ranges but does not report exact numerical values, effect sizes, or confidence intervals.
Why it matters
This study provides an in vitro mechanistic basis showing that PDE5 inhibitors may directly influence local steroidogenesis and favor androgenic over estrogenic signaling in bone-derived target cells.
Limits
The study is restricted to an in vitro model using a single osteoblast-like cell line (SAOS-2), which may not reflect human in vivo physiology or tissue pharmacokinetics. The abstract lacks quantitative effect estimates, standard deviations, and exact statistical test metrics. No clinical or animal in vivo outcomes were evaluated.
Cited by
- partial Tadalafil upregulates either the sensitivity or the number of androgen receptors, enhancing the body's response to circulating testosterone.