title: Effect of follicular aspiration just before ovulation on corpus luteum characteristics, circulating progesterone concentrations and uterine receptivity in single-ovulating and superstimulated heifers.
abstract: The aim of this study was to investigate, in unstimulated and superstimulated heifers, the effect of follicle aspiration just before ovulation on corpus luteum (CL) development, circulating progesterone (P(4)) concentrations and the ability of the uterus to support embryo development. Following follicle aspiration or ovulation timed from GNRH administration, CL development was assessed by daily ultrasonography, and CL function was assessed in terms of the capacity to produce P(4) and the expression of genes involved in steroidogenesis in luteal tissue. The capacity of the uterine environment to support conceptus development was assessed following transfer and recovery of in vitro-produced embryos. Follicular aspiration just before the expected time of ovulation leads to a significant reduction in CL diameter, CL area and area of luteal tissue. This was associated with a decrease in circulating P(4) in both unstimulated and superstimulated heifers. Follicle aspiration leads to a reduction in conceptus length and area on day 14 in unstimulated heifers only. Follicle aspiration leads to a reduction in the expression of LHCGR in luteal tissue from unstimulated heifers compared with those in which the CL formed after ovulation. Superstimulation significantly reduced the expression of STAR in luteal tissue in both ovulated and follicle-aspirated heifers. In conclusion, in stimulated and unstimulated heifers, aspiration of the preovulatory dominant follicle(s) just before expected ovulation interferes with the subsequent formation and function of the CL, in terms of size and P(4) output and this, in turn, is associated with a reduced capacity of the uterus to support conceptus elongation in unstimulated heifers.
authors.affiliation: School of Agriculture and Food Science, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: L
authors.initials: L
authors.lastname: O'Hara
authors.forename: S
authors.initials: S
authors.lastname: Scully
authors.forename: V
authors.initials: V
authors.lastname: Maillo
authors.forename: A K
authors.initials: AK
authors.lastname: Kelly
authors.forename: P
authors.initials: P
authors.lastname: Duffy
authors.forename: F
authors.initials: F
authors.lastname: Carter
authors.forename: N
authors.initials: N
authors.lastname: Forde
authors.forename: D
authors.initials: D
authors.lastname: Rizos
authors.forename: P
authors.initials: P
authors.lastname: Lonergan
mesh_terms: D000818:Animals; D002417:Cattle; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000235:genetics / Q000378:metabolism; D003338:Corpus Luteum / Q000000981:diagnostic imaging / Q000378:metabolism*; D010064:Embryo Implantation; D004624:Embryo Transfer / Q000662:veterinary; D005260:Female; D005300:Fertility Agents, Female / Q000008:administration & dosage; D005307:Fertilization in Vitro / Q000662:veterinary; D005786:Gene Expression Regulation; D007987:Gonadotropin-Releasing Hormone / Q000008:administration & dosage; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism; D006080:Ovarian Follicle / Q000378:metabolism*; D010062:Ovulation Induction / Q000009:adverse effects / Q000662:veterinary*; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D011374:Progesterone / Q000097:blood*; D011375:Progesterone Reductase / Q000235:genetics / Q000378:metabolism; D013251:Steroid Isomerases / Q000235:genetics / Q000378:metabolism; D013396:Suction / Q000009:adverse effects / Q000662:veterinary*; D013480:Superovulation; D013997:Time Factors; D014463:Ultrasonography; D014599:Uterus / Q000378:metabolism*; D000098682:Steroidogenic Acute Regulatory Protein
chemical_list: C021425:3 beta-hydroxysteroid oxidoreductase-delta(5) 3-ketosteroid isomerase; D005300:Fertility Agents, Female; D009097:Multienzyme Complexes; D010750:Phosphoproteins; D000098682:Steroidogenic Acute Regulatory Protein; D007987:Gonadotropin-Releasing Hormone; D011374:Progesterone; D011375:Progesterone Reductase; D002786:Cholesterol Side-Chain Cleavage Enzyme; D013251:Steroid Isomerases