title: Leptin and leptin receptor gene expression in the canine corpus luteum during diestrus, pregnancy and after aglepristone-induced luteolysis.
abstract: Leptin (LEP) and leptin receptor (LEP-R) expression was shown to change throughout the luteal phase in several species and may be involved in steroid hormone production. In the bitch, leptin but not LEP-R protein was detected in the non-pregnant corpus luteum (CL). Until now, no further information has been available on their expression levels and role in CL function. Our objective was to compare time-related changes in luteal LEP and LEP-R mRNA levels during the non-pregnant luteal phase, pregnancy and after aglepristone treatment in mid-gestation. CLs were collected by ovariohysterectomy at different time points: day (d) 5, 15, 25, 35, 45, 65 after ovulation (p.o.) in non-pregnant bitches; pre-implantation, post-implantation, mid-gestation, during prepartum luteolysis; 24 and 72 h after aglepristone injection. Non-pregnant LEP expression was lowest on d5 p.o., increased thereafter and fell again on d45 (P ≤ 0.04). LEP-R expression was not altered (P = 0.07). In pregnant bitches, neither LEP nor LEP-R mRNA levels varied over time (P = 0.201 and P = 0.150, respectively). Aglepristone treatment caused substantial downregulation of luteal LEP expression by 72 h post-treatment (P ≤ 0.01). However, LEP-R expression did not follow the same course (P = 0.193). Our results indicate that both LEP and LEP-R mRNA are present in the canine CL during the non-pregnant luteal phase and pregnancy. LEP expression changes significantly over time in non-pregnant dogs and after aglepristone administration and thus, it may play a role in luteal steroidogenesis and regression.
authors.affiliation: Vetsuisse Faculty, Clinic for Reproductive Medicine, University of Zurich, Zurich, Switzerland. obalogh@vetclinics.uzh.ch
authors.forename: O
authors.initials: O
authors.lastname: Balogh
authors.forename: M P
authors.initials: MP
authors.lastname: Kowalewski
authors.forename: I M
authors.initials: IM
authors.lastname: Reichler
mesh_terms: D000818:Animals; D004031:Diestrus / Q000502:physiology; D004285:Dogs / Q000502:physiology*; D004963:Estrenes / Q000494:pharmacology*; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology*; D020738:Leptin / Q000235:genetics / Q000378:metabolism*; D003341:Luteolysis / Q000187:drug effects*; D011247:Pregnancy; D054411:Receptors, Leptin / Q000235:genetics / Q000378:metabolism*
chemical_list: D004963:Estrenes; D020738:Leptin; D054411:Receptors, Leptin; C419063:aglepristone