Non-invasive method of obtaining milk from mice using carbetocin, a synthetic analogue of oxytocin

Abstract

IntroductionThe mouse is an important laboratory animal in pharmacological and toxicological research. However, there is a limited ability to analyse the penetration of tested substances in mouse breastmilk, which is technically difficult to obtain in sufficient quantities. The aim of the study is to verify the use of carbetocin for this purpose. MethodsThe effect of carbetocin (20 and 40 μg per animal) was tested in nursing ICR females that had milk collected for 15 min, started 1.5 min after administration. At a higher dose, carbetocin was also tested with a 20-min collection, started 7 min after application. Oxytocin (2 IU per animal) and saline were used as positive and negative controls, respectively. ResultsMilk yield using a lower dose of carbetocin was comparable to oxytocin. However, the duration of action of carbetocin was longer than that of oxytocin. A higher doses of carbetocin resulted in significantly higher milk volumes. DiscussionThe use of carbetocin has proven to be an effective non-invasive method to obtain up to 0.89 g of milk from one mouse in 20 min.