Storey, A.E., Ralph, T. M., & Evans, J. H. (1999). Does prolactin determine when lactating voles return to their pups? Poster presented at the meeting of the Society for Neuroscience, Miami Beach, USA, November.


We examined whether prolactin depletion affected maternal behavior more when females were in large enclosures, where they experienced less attracting stimulation from the more distant pups when they left the nest to forage. Following injection with 150 mg/kg cysteamine hydrochloride, females in large enclosures spent significantly less time with pups compared to drug-treated females in regular sized cages. Compared to controls, drug-treated females in large enclosures spent more time away from pups each time they left the nest, but when they returned, average nest bout duration was not significantly shorter. These results suggest that prolactin may be involved in attracting the foraging female back to the nest to interact with pups. Prolactin depletion affected maternal behavior more on pup Day 2 than on Day 12, consistent with previous research that hormones are more important before the transition to the pup-maintained phase of pup rearing. Thus, prolactin may play a role in establishing a pattern of alternation between nest visits and foraging bouts early in lactation.