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Prostaglandin F 2α ‐Induced Nest‐Building Behaviour is Associated with Increased Hypothalamic c‐ fos and c‐ jun mRNA Expression
Author(s) -
Walton S. L.,
Burne T. H. J.,
Gilbert C. L.
Publication year - 2002
Publication title -
journal of neuroendocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.062
H-Index - 116
eISSN - 1365-2826
pISSN - 0953-8194
DOI - 10.1046/j.1365-2826.2002.00831.x
Subject(s) - prostaglandin f2alpha , luteolysis , endocrinology , medicine , supraoptic nucleus , hypothalamus , estrous cycle , biology , c fos , corpus luteum , pars tuberalis , intramuscular injection , prostaglandin , gene expression , pituitary gland , ovary , hormone , biochemistry , gene
Intramuscular injection of the naturally occurring prostaglandin F 2α (PGF 2α ) to sexually mature female pigs induces luteolysis and rapidly elicits a behavioural response consistent with pre‐partum nest‐building. Intramuscular injection of the synthetic prostaglandin F 2α (cloprostenol) also induces luteolysis but no nest‐building behaviour is observed. The effects of PGF 2α , but not cloprostenol, on nest‐building behaviour may be mediated via peripheral PGF 2α 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 c‐ fos and c‐ jun mRNA after treatment with PGF 2α or cloprostenol. Twenty‐one 8‐month‐old nulliparous female pigs (gilts) were injected intramuscularly with a luteolytic dose of PGF 2α (15 mg), cloprostenol (175 µg) 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 c‐ fos and c‐ jun genes using standard in situ hybridization histochemistry techniques. Significantly higher c‐ fos and c‐ jun mRNA expression was found in PGF 2α ‐treated compared to saline or cloprostenol‐treated pigs in the PVN, SON and SOD. Significantly higher c‐ fos and c‐ jun mRNA expression was found in corpus lutea of PGF 2α and cloprostenol‐treated pigs compared to saline controls. Treatment with PGF 2α induced nest‐building behaviour whereas treatment with cloprostenol and saline did not. This suggests that PGF 2α , or one of its metabolites, and not cloprostenol, crosses the blood–brain barrier and acts directly on hypothalamic receptors to mediate its effect on nest‐building behaviour.