title: Ovulation rate and its relationship with follicle diameter and gene expression of the LH receptor (LHR) in Nelore cows.
abstract: The objective was to determine the relationship among the diameter of ovarian follicles, ovulation rate, and gene expression of the LH receptor (LHR) in Nelore cattle. In Experiment 1, ovulation was synchronized in 53 Nelore cows. Three days after ovulation, ovaries were assessed with ultrasonography, all cows were given 6.25 mg LH im, and they were allocated into three groups, according to diameter of their largest ovarian follicle: G1 (7.0-8.0 mm); G2 (8.1-9.0 mm); and G3 (9.1-10.0 mm). For these three groups, ovulation rates were 9, 36, and 90%, respectively, (P<0.03; each rate differed significantly from the other two). In Experiment 2, granulosa and theca cells were subjected to total RNA extraction, and gene expression of the LHR was determined by RT-PCR. Follicles were allocated in three groups based on their diameter (similar to the Experiment 1), which were denoted Groups A, B, and C. Expression of the LHR gene in granulosa cells was lower in Group A than Group C (P<0.05). However, there were no significant differences among groups in expression of the LHR gene in theca cells. We concluded that ovulatory capacity in Nelore cattle was related to increased follicular diameter and expression of the LHR gene in granulosa cells.
authors.affiliation: Department of Pharmacology, Institute of Biosciences, University of Sao Paulo State (UNESP), Botucatu-SP, Brazil.
authors.forename: Renato A L
authors.initials: RA
authors.lastname: Simões
authors.forename: Rafael A
authors.initials: RA
authors.lastname: Satrapa
authors.forename: Fernanda S
authors.initials: FS
authors.lastname: Rosa
authors.forename: Marcelo
authors.initials: M
authors.lastname: Piagentini
authors.forename: Anthony C S
authors.initials: AC
authors.lastname: Castilho
authors.forename: Ronaldo L
authors.initials: RL
authors.lastname: Ereno
authors.forename: Luzia A
authors.initials: LA
authors.lastname: Trinca
authors.forename: Marcelo F G
authors.initials: MF
authors.lastname: Nogueira
authors.forename: José
authors.initials: J
authors.lastname: Buratini
authors.forename: Ciro M
authors.initials: CM
authors.lastname: Barros
mesh_terms: D000818:Animals; D002417:Cattle / Q000502:physiology*; D004973:Estrus Synchronization; D005260:Female; D015870:Gene Expression; D006080:Ovarian Follicle / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D010060:Ovulation / Q000502:physiology*; D011974:Receptors, LH / Q000235:genetics* / Q000502:physiology; D014463:Ultrasonography
chemical_list: D011974:Receptors, LH