Endocrine Abstracts

Endocrine-disrupting chemicals (EDCs) are structures similar to steroids hormones which can interfere with hormone synthesis and normal physiological functions of male and female reproductive organs. EDCs tend to bind to steroid hormone receptors. Sex steroid hormones influence calcium signaling of the cardiac muscle in early embryo-development. Progesterone (P4) has been reported to affect both blood pressure and other aspects of the cardiovascular system. To confirm the affect of progesterone (P4), octyl-phenol (OP) and bisphenol A (BPA) on early differentiation of mouse embryonic stem (ES) cells into cardiomyocytes, the hanging-drop method was performed to form embryoid bodies. The mouse embryoid bodies (mEB) were suspended, attached onto 6 well plates and cultured in differentiation medium containing steroid-free FBS without LIF. P4, OP and BPA were treated at two days after attachment and media were replaced every two days. To investigate the calcium signaling, the mRNA level of calcium channel genes such as Trpv2 and contraction-related genes such as Ryr2, Cam2 and Mlck3 was analysed. In addition, mifepristone (RU486), which is a synthetic steroid that has an affinity for PR, was used to confirm the impact of P4 through PR. To determine if RU486 is capable of attenuating the inhibition effect, RU486 was applied for one day starting on day 11. Trpv2, Ryr2, Calm2 and Mlck3 decreased in the P4-treated group. RU486 treatment led to recovery of the decreased of cytosolic calcium-related genes in parallel with a reduction in the of PR. Treatment of OP and BPA were alter the of calcium channel and muscle-contraction related genes. These findings maybe be useful for screening EDCs during cardiac developmental process.