Variability in Oxytocin Blood Levels in Rats: A Review and Experimental Insights

Oxytocin, often called the "love hormone," is well-known for its roles in childbirth and lactation. Beyond these traditional functions, it plays a vital role in emotional and social behaviors, mood regulation, stress responses, and various physiological processes. Blood oxytocin levels are typically low under basal conditions but increase significantly during labor, breastfeeding, sexual activity, and positive social interactions. However, reported plasma oxytocin levels in humans and rodents vary widely across studies. In this study, we reviewed plasma oxytocin levels in rats from research conducted over the past decade, emphasizing the notable discrepancies observed between studies. Furthermore, we investigated the effects of two anesthetic protocols (inhaled isoflurane and a combination of three anesthetics) and the proteinase inhibitor aprotinin on plasma oxytocin levels in adult male rats. Our findings revealed that neither the anesthetics nor aprotinin significantly affected plasma oxytocin levels. We also discussed potential factors contributing to the marked differences in reported rat blood oxytocin levels.