Relative Contribution of Nuclear and Membrane Progesterone Receptors in Respiratory Control

Progesterone is a steroid hormone whose physiological effects can affect various systems, including reproductive, immune and cardiorespiratory systems. In fact, there are growing evidences proving that progesterone is potent respiratory stimulant with therapeutic value for sleep-disordered breathing. However there is no clear understanding of how progesterone mediates its stimulant respiratory effects and alleviates apnea. Mechanistically, it was demonstrated that this hormone elicits some of its respiratory effect via the classical mechanism of the nuclear progesterone receptor (nPR), a transcription factor belonging to the super family of steroid hormone receptors. Moreover, experimental results indicate that activation of alternative non-genomic (i.e. non-nuclear) signaling pathways such as the membrane progesterone receptors (mPR) could have a key role in the regulation of the respiratory control system. We provide preliminary results suggesting an important role of mPRβ on respiratory control and ventilatory response to hypoxia in adult female mice.