Infant-directed behaviour in the naturally paternal male dwarf hamster, Phodopus campbelli, is neither activationally nor organizationally regulated by activity at the progesterone receptor

dc.contributor.authorThorpe, Joelleen
dc.contributor.departmentBiologyen
dc.contributor.supervisorWynne-Edwards, Katherine E.en
dc.date2009-09-04 13:23:18.733
dc.date.accessioned2009-09-04T19:09:13Z
dc.date.available2009-09-04T19:09:13Z
dc.date.issued2009-09-04T19:09:13Z
dc.degree.grantorQueen's University at Kingstonen
dc.descriptionThesis (Master, Biology) -- Queen's University, 2009-09-04 13:23:18.733en
dc.description.abstractPhodopus campbelli is a naturally biparental dwarf hamster with males so paternal they will act as midwives during the birth of their litter. The hormonal regulation of parental behaviour has been well established in many species. However, to date, no causal mechanism for the extensive paternal behaviour displayed by male P. campbelli has been discovered. Recently, activity at the progesterone receptor has been shown to inhibit infant-directed behaviour in male mice. Therefore, the first study in this thesis was carried out to determine if antagonism of the progesterone receptor (PR) would enhance infant-directed care behaviour in naïve P. campbelli males. Despite detectable serum progesterone concentration in males, PR antagonism did not alter progesterone concentration, nor did it alter infant-directed behaviour in males with antagonized PR in adulthood. A slight increase in the latency to retrieve a pup seen in males with antagonized PR during adolescence suggests that there may be a developmental effect of PR activity on infant-directed behaviour in adulthood. Neonatal male rats express high levels of PR in brain regions important for parental behaviour. Since hormones can act very early in life to organize adult behaviour, the second study was carried out to determine if progesterone acting much earlier than adolescence is important in the regulation of paternal behaviour in P. campbelli adulthood. Males were treated daily for the first week of life with transdermal progesterone, which increased neonatal serum progesterone concentration fivefold. Despite the significant increase in progesterone (and therefore presumably activity at the PR), male behaviour in three different stages of adulthood (sexually naïve, during the birth of the male’s first litter, and in new fatherhood) towards pups was not altered. Measures of paternal contribution such as pup weight throughout the lactational period were altered by progesterone treatment during the neonatal period, but litter quality was ultimately high in both groups. Therefore, activity at the PR in adulthood, puberty, or during the neonatal period does not inhibit paternal behaviour in the naturally biparental hamster, P. campbelli. Thus, progesterone and its receptor do not organizationally or activationally regulate paternal behaviour in P. campbelli.en
dc.description.degreeM.Sc.en
dc.format.extent5600390 bytes
dc.format.mimetypeapplication/pdf
dc.identifier.urihttp://hdl.handle.net/1974/5135
dc.language.isoengen
dc.relation.ispartofseriesCanadian thesesen
dc.rightsThis publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.en
dc.subjectprogesteroneen
dc.subjectdwarf hamsteren
dc.subjectRU486en
dc.subjectpaternal behaviouren
dc.titleInfant-directed behaviour in the naturally paternal male dwarf hamster, Phodopus campbelli, is neither activationally nor organizationally regulated by activity at the progesterone receptoren
dc.typethesisen
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