Trequinsin (hydrochloride)

Trequinsin hydrochloride (HL 725) is a PDE inhibitor, CatSper channel activator, and sperm potassium channel modulator. Trequinsin hydrochloride targets PDE3 with an IC₅₀ of <1 nM. Trequinsin hydrochloride enhances currents and elevates intracellular calcium and cGMP levels via direct activation of the CatSper channel, while inhibiting the outward current conductance of sperm potassium channels. Without inducing premature acrosome reaction, Trequinsin hydrochloride significantly enhances sperm hyperactivated motility, forward motility, and the ability to penetrate viscous media. Trequinsin hydrochloride exerts age-specific positive inotropic and positive lusitropic effects on rabbit ventricular papillary muscles. Trequinsin hydrochloride has been used in studies on the mechanisms underlying male infertility (e.g., asthenozoospermia)^[1][2]. In Vitro:Trequinsin hydrochloride (40 μM; 82 min) induces a high-magnitude increase in intracellular calcium in pooled capacitated human donor sperm, equivalent to 91% of the response evoked by 10 μM Progesterone (HY-N0437)^[1].
Trequinsin hydrochloride (0.1-30 μM) induces a concentration-dependent increase in intracellular calcium in capacitated human donor sperm with an EC₅₀ of 3.43 μM, exhibits efficacy equivalent to progesterone at 10 μM, and cross-desensitises with PGE₁ but not progesterone^[1].
Trequinsin hydrochloride (10 μM; 120 min) significantly and sustainably increases hyperactivated motility in capacitated human donor sperm (80% density gradient centrifugation fraction) without altering total or progressive motility^[1].
Trequinsin hydrochloride (10 μM; 120 min) significantly increases progressive motility in poor-motility human donor sperm (40% density gradient centrifugation fraction) under both capacitating and non-capacitating conditions, and increases hyperactivated motility under capacitating conditions^[1].
Trequinsin hydrochloride (10 μM; 120 min) increases hyperactivated motility in the majority of capacitated human patient sperm samples, with no effect on total or progressive motility in most cases^[1].
Trequinsin hydrochloride (10 μM; 20 min) does not induce premature acrosome reaction in capacitated human donor sperm^[1].