Abstract
Prostaglandins E and F have been shown to be present in breast milk in over 100 times the concentrations found in adult plasma. The ratio of the concentration of the principal circulating metabolite of prostaglandin F (13, 14-dihydro-15-ketoprostaglandin F) to prostaglandin F itself is low (0.3 to 0.5, compared with 15.8 in adult plasma), implying that prostaglandins may have a relatively long half-life in milk. In addition inactive metabolites of thromboxane A2 and prostacyclin are also found in significant amounts. It is speculated that milk prostaglandin play a role in modulating neonatal physiology--for example, gut motility.