Oxytocin modulates a wide variety of social behaviors including maternal care, pair bonding, aggression, social memory, social cooperation, social reward, social information processing, and more. My recent paper found that vitamin D may increases the expression of the gene that makes the oxytocin pre-peptide!
Here, researchers found that injecting oxytocin into aging mice was able to repair muscle in the old mice (about 80 percent of what we saw in the young mice).