Oxytocin signaling involves which G protein?

Oxytocin signaling primarily involves the Gq protein, which plays a crucial role in mediating the cellular responses to this hormone. When oxytocin binds to its receptor on target cells, it activates the Gq protein. This activation leads to the stimulation of phospholipase C (PLC), which catalyzes the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) into inositol trisphosphate (IP3) and diacylglycerol (DAG).

The resultant IP3 then triggers the release of calcium ions from the endoplasmic reticulum, increasing intracellular calcium levels. This rise in calcium concentration is critical for various biological processes, including muscle contraction during childbirth and milk ejection during breastfeeding. Meanwhile, DAG can activate protein kinase C (PKC), further contributing to the signal transduction pathway.

Essentially, the Gq protein plays an integral role in the oxytocin signaling pathway by facilitating the rise in intracellular calcium and activating other signaling cascades, which are fundamental to the physiological functions that oxytocin regulates.