title: Modulation of periovulatory endocrine profiles in beef cows: consequences for endometrial glucose transporters and uterine fluid glucose levels.
abstract: In beef cattle, proestrus estradiol and subsequent progesterone (P4) concentrations can regulate the endometrial characteristics and thereby determine maternal receptivity toward the embryo. However, the underlying mechanisms linking periovulatory endocrine profiles to receptivity, which is crucial to obtain pregnancy, need to be elucidated. We hypothesized that the size of the preovulatory follicle (POF) and subsequent circulating P4 concentrations, during early diestrus, modulate endometrial levels of glucose transporter transcripts and proteins, and subsequently affect the luminal glucose availability in the uterus. Therefore, follicle growth of Nelore cows was manipulated, and cows were assigned to 2 experimental groups: (1) large follicle and large corpus luteum (LF-LCL) group with a large POF and corpus luteum (CL); and (2) small follicle and small corpus luteum (SF-SCL) group with a small POF and CL. At day 7 post gonadotropin-releasing hormone induced ovulation (gonadotropin-releasing hormone treatment = day 0), animals were slaughtered (n = 18 per group), and uterine tissues and washings were collected for characterization of glucose transporters and glucose levels, respectively. The diameter of POF was larger (P < 0.05) in the LF-LCL cows compared with their SF-SCL counterparts (12.8 ± 0.4 vs 11.1 ± 0.4 mm). Furthermore, CL size (17.49 ± 0.88 vs 14.48 ± 0.52 mm) and circulating P4 concentrations at day 7 (4.5 ± 1.0 vs 3.3 ± 1.1 ng/mL, P < 0.05) were significantly higher in the LF-LCL cows compared with the SF-SCL cows. No differences (P > 0.05) were detected in gene expression patterns of SLC2A1, SLC2A3, SLC2A4, SLC2A5, SLC5A1, ATP1A2, ATP1B2, and SLC37A4. However, the protein abundance of endometrial SLC2A1was increased in the LF-LCL group compared with the SF-SCL group (P < 0.05). SLC2A1 and SLC2A4 protein products were mainly identified at the endometrial luminal and glandular epithelium membranes as well as in the endometrial stroma. Glucose concentrations in uterine washings were similar between groups. In conclusion, we provided information on the potential link between endocrine profiles and glucose transport pathways in the bovine endometrium. More specifically, our data reveal that the size of the POF, and subsequent P4 concentrations, do not functionally affect the main endometrial glucose transporter pathways or uterine fluid glucose concentrations during diestrus.
authors.affiliation: Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, Pirassununga, São Paulo, Brazil.
authors.forename: M R
authors.initials: MR
authors.lastname: França
authors.affiliation: Veterinary Medicine, Federal University of Pampa, Uruguaiana, Rio Grande do Sul, Brazil.
authors.forename: F S
authors.initials: FS
authors.lastname: Mesquita
authors.affiliation: Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, Pirassununga, São Paulo, Brazil.
authors.forename: E
authors.initials: E
authors.lastname: Lopes
authors.affiliation: Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, Pirassununga, São Paulo, Brazil.
authors.forename: G
authors.initials: G
authors.lastname: Pugliesi
authors.affiliation: Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, Pirassununga, São Paulo, Brazil.
authors.forename: V
authors.initials: V
authors.lastname: Van Hoeck
authors.affiliation: Department of Genetic and Evolution, Federal University of São Carlos, São Carlos, São Paulo, Brazil.
authors.forename: M R
authors.initials: MR
authors.lastname: Chiaratti
authors.affiliation: College of Animal Science, University of São Paulo State, Dracena, São Paulo, Brazil.
authors.forename: C B
authors.initials: CB
authors.lastname: Membrive
authors.affiliation: Department of Surgery, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, São Paulo, Brazil.
authors.forename: P C
authors.initials: PC
authors.lastname: Papa
authors.affiliation: Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, Pirassununga, São Paulo, Brazil. Electronic address: binelli@usp.br.
authors.forename: M
authors.initials: M
authors.lastname: Binelli
mesh_terms: D000818:Animals; D001826:Body Fluids / Q000737:chemistry*; D002417:Cattle / Q000097:blood / Q000502:physiology*; D003338:Corpus Luteum / Q000502:physiology; D004717:Endometrium / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology; D005947:Glucose / Q000737:chemistry*; D051246:Glucose Transport Proteins, Facilitative / Q000378:metabolism*; D006080:Ovarian Follicle / Q000502:physiology; D010060:Ovulation / Q000097:blood / Q000502:physiology*; D011247:Pregnancy; D011374:Progesterone
chemical_list: D051246:Glucose Transport Proteins, Facilitative; D011374:Progesterone; D005947:Glucose
keywords: Bovine; Ovary; Solute carrier protein; Uterus