Effects of oxytocin outside pregnancy.

For a long time, oxytocin was regarded as a pregnancy hormone released by the hypophysis to stimulate labour and milk ejection. In the present survey, data have been collected from the literature to show the spectrum of the hitherto known functions of oxytocin outside pregnancy. It is now known that oxytocin receptors can occur almost ubiquitously in the organism, that oxytocin is also formed outside of the brain and that oxytocin has functions in a number of organs. In the first part of the survey, stimuli that contribute to an increase in oxytocin release are compiled. In the second part, details are given on the individual oxytocin targets. Although the majority of findings are based on the results of animal experiments, there are already a number of studies that indicate similar effects of oxytocin in humans. According to the current state of knowledge, oxytocin appears to be involved in functions in the following organs: male and non-pregnant female reproductive tract, pancreas, cardiovascular system, kidney, brain and breast. There are indications that oxytocin may also have actions in other organs. There continues to be a considerable need for research into oxytocin in order to better understand the physiological and pathophysiological actions and to be able to derive possible therapeutic uses. Further light on the spectrum of functions of oxytocin may be cast by the possibility of the use of oxytocin antagonists. Copyright 2003 S. Karger AG, Basel