Intramuscular injection of the naturally occurring @entity3774 (PGF2alpha) to sexually mature female @entity1707 induces luteolysis and rapidly elicits a behavioural response consistent with pre-partum nest-building. Intramuscular injection of the synthetic @entity3774 ( @entity2669 ) also induces luteolysis but no nest-building behaviour is observed. The effects of PGF2alpha, but not @entity2669 , on nest-building behaviour may be mediated via peripheral PGF2alpha receptors (FP) or via direct action on central FP receptors. We have previously shown FP receptor mRNA to be localized in porcine paraventricular nucleus (PVN), supraoptic nucleus (SON) and pars dorso-medialis of the suproptic nucleus (SOD), suprachiasmatic nucleus, choroid plexus and anterior and intermediate pituitary lobes. In this experiment, we examined hypothalamic expression of the immediate early genes @entity51876 and @entity26105 mRNA after treatment with @entity3774 or @entity2669 . Twenty-one 8-month-old nulliparous female @entity1707 (gilts) were injected intramuscularly with a luteolytic dose of PGF2alpha (15 mg), @entity2669 (175 microg) or saline control, their behaviour was recorded and they were killed 60 min later. Coronal hypothalamic sections and control ovarian tissues were incubated with 45-mer oligonucleotide probes complementary to porcine @entity51876 and @entity26105 genes using standard in situ hybridization histochemistry techniques. Significantly higher @entity51876 and @entity26105 mRNA expression was found in PGF2alpha-treated compared to saline or @entity2669 -treated @entity1707 in the PVN, SON and SOD. Significantly higher @entity51876 and @entity26105 mRNA expression was found in corpus lutea of PGF2alphaand @entity2669 -treated @entity1707 compared to saline controls. Treatment with PGF2alpha induced nest-building behaviour whereas treatment with @entity2669 and saline did not. This suggests that PGF2alpha, or one of its metabolites, and not @entity2669 , crosses the blood-brain barrier and acts directly on hypothalamic receptors to mediate its effect on nest-building behaviour.

@entity3774 -induced nest-building behaviour is associated with increased hypothalamic XXXX and @entity26105 mRNA expression.

@entity1707 :: ('9823', 'Species') :: ['pigs'] @entity2669 :: ('MESH:D003008', 'Chemical') :: ['cloprostenol'] @entity3774 :: ('MESH:D015237', 'Chemical') :: ['PGF2alpha', 'prostaglandin F2alpha'] @entity51876 :: ('100144486(Tax:9823)', 'Gene') :: ['c-fos'] @entity26105 :: ('396913(Tax:9823)', 'Gene') :: ['c-jun']
@entity51876 :: (100144486(Tax:9823),Gene) :: ['c-fos']
