title: The effect of elevated progesterone and pregnancy status on mRNA expression and localisation of progesterone and oestrogen receptors in the bovine uterus.
abstract: To investigate the effects of pregnancy or post-ovulatory progesterone (P(4)) supplementation on the expression of oestrogen and P(4) receptors (ESRs and PGRs) in the bovine uterus, heifers (n=263) were randomly assigned to the following treatments: i) cyclic, normal P(4); ii) cyclic, high P(4); iii) pregnant, normal P(4); and iv) pregnant, high P(4) on days 5, 7, 13 and 16 of pregnancy/oestrous cycle. Elevated P(4) was achieved through P(4)-releasing intravaginal device insertion on day 3 after oestrus, resulting in increased concentrations from day 3.5 to 8 (P<0.05) in the high groups than in the normal groups. Irrespective of treatment, PGR and ESR1 mRNA expressions were highest on days 5 and 7 and decreased on day 13 (P<0.05), while ESR2 mRNA expression increased on day 7 (P<0.05) and similar levels were maintained within the normal P(4) groups subsequently. Expression in the high P(4) groups decreased on day 13 (P<0.05). PGR-AB and PGR-B protein expressions were high in the luminal and superficial glands on days 5 and 7, but by day 13, expression had declined to very low or undetectable levels and high P(4) concentration tended to decrease or decreased significantly (P<0.05) the expression in these regions on days 5 and 7. ESR1 protein expression was high, with no treatment effect. ESR2 protein was also highly expressed, with no clear effect of treatment. In conclusion, early post-ovulatory P(4) supplementation advances the disappearance of PGR protein from the luminal epithelium on days 5 and 7, and decreases ESR2 mRNA expression during the mid-luteal phase, but has no effect on PGR or ESR1 mRNA expression.
authors.affiliation: School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: L A
authors.initials: LA
authors.lastname: Okumu
authors.forename: N
authors.initials: N
authors.lastname: Forde
authors.forename: A G
authors.initials: AG
authors.lastname: Fahey
authors.forename: E
authors.initials: E
authors.lastname: Fitzpatrick
authors.forename: J F
authors.initials: JF
authors.lastname: Roche
authors.forename: M A
authors.initials: MA
authors.lastname: Crowe
authors.forename: P
authors.initials: P
authors.lastname: Lonergan
mesh_terms: D000818:Animals; D002417:Cattle; D015536:Down-Regulation; D047628:Estrogen Receptor alpha / Q000096:biosynthesis; D047629:Estrogen Receptor beta / Q000096:biosynthesis; D030762:Estrous Cycle; D005260:Female; D007150:Immunohistochemistry; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000097:blood*; D011374:Progesterone / Q000097:blood*; D011506:Proteins / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis*; D011960:Receptors, Estrogen / Q000096:biosynthesis*; D011980:Receptors, Progesterone / Q000096:biosynthesis*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014599:Uterus / Q000378:metabolism*
chemical_list: D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D011506:Proteins; D012333:RNA, Messenger; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D011374:Progesterone