UC Davis

The mammary gland (MG) is a remarkable tissue that undergoes a number of stages ofepithelial growth and differentiation and is regulated by hormones such as prolactin (PRL). Recent research has found that binucleated cells (BNC) in the MG of mice form at the time of late gestation and remain until the termination of lactation, although their functional purpose is unknown. In order to improve the understanding of their development pattern, we aimed to quantify the abundance of BNC in the MG of primiparous pigs (n=4) from late gestation day 90 through lactation day 21. Further, we used hyperprolactinemic primiparous gilts (n=4) treated with the dopamine antagonist domperidone (DOM) to test the latter’s effect on the abundance of BNC within the MG during the same period. The cellular architecture was assessed by three-dimensional confocal microscopy and immunofluorescent staining. Our results indicate that BNC abundance increased during the gestation-lactation window to reach maximal levels on day 21 of lactation. We also found that DOM-treated gilts had a significantly greater incidence of BNC compared to controls (p < .05) and that on lactation day 21 there was a statistically greater number of BNCs in DOM-treated sows (p < .05). These findings demonstrate that not only do BNCs exist in the porcine MG but, that they may play a functional role during lactogenesis.