title: Serum hormones, follicular fluid steroids, insulin-like growth factors and their binding proteins, and ovarian IGF mRNA in sheep with different ovulation rates.
abstract: Ovulation rate, serum hormone concentrations, follicular fluid (FFL) concentrations of steroids and IGF, IGF binding protein (IGFBP) activity in FFL, and follicular IGF-I and -II mRNA were compared during the follicular phase among five genotypes of ewes: Finn (F), Composite III (C), 1/2 Booroola Merino (B) x 1/2 F (B x F), 1/2 F x 1/2 C (F x C), 1/2 B x 1/2 C (B x C). Composite III ewes were a Columbia x Suffolk x Hampshire crossbred. Ovulation rates for F (n = 7), C (n = 5), B x F (n = 6), F x C (n = 3), and B x C (n = 8) ewes were 3.1, 1.6, 3.8, 2.9, and 2.9 (Pooled SEM = .5), respectively. Concentrations of IGF-I in FFL were 53% greater (P < .05) in large (> or = 4.1 mm) than in small (< 4.1 mm) follicles but did not differ (P > .10) among genotypes. In contrast, FFL IGF-II concentrations were greater (P < .05) in B x C and B x F ewes than in C or F x C ewes but did not differ between small and large follicles. Ligand blotting revealed that IGFBP activity of three species (34, 27 to 29, and 24 kDa) were lower (P < .05) in FFL of large than in FFL of small follicles but did not differ (P < .10) among genotypes. Follicular wall IGF-I mRNA and IGF-II mRNA was detected in 5 and 32% of the samples from preovulatory follicles, respectively, using reverse transcriptase-PCR and ethidiumbromide staining. Ovarian IGF-I mRNA levels, assessed by Northern analysis, in B x F and B x C ewes were greater (P < .05) than those in C ewes; ovarian IGF-I mRNA levels in F and F x C ewes were intermediate and did not differ (P > .10) from those in C ewes. Small follicles from B x C and B x F ewes had severalfold greater (P < .05) estradiol concentrations than those from F or C ewes, whereas large follicles from B x F ewes had twice (P < .05) the estradiol concentrations of follicles from F or C ewes. Progesterone in FFL did not differ among genotypes. Serum LH, FSH, inhibin, IGF-I, and progesterone did not differ (P > .10) among genotypes.(ABSTRACT TRUNCATED AT 400 WORDS)
authors.affiliation: Department of Animal Science, Oklahoma State University, Stillwater 74078, USA.
authors.forename: L J
authors.initials: LJ
authors.lastname: Spicer
authors.forename: S E
authors.initials: SE
authors.lastname: Echternkamp
authors.forename: E A
authors.initials: EA
authors.lastname: Wong
authors.forename: D T
authors.initials: DT
authors.lastname: Hamilton
authors.forename: R K
authors.initials: RK
authors.lastname: Vernon
mesh_terms: D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002352:Carrier Proteins / Q000032:analysis; D003433:Crosses, Genetic; D017931:DNA Primers / Q000737:chemistry; D004958:Estradiol / Q000032:analysis / Q000097:blood / Q000378:metabolism; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D015571:Follicular Fluid / Q000737:chemistry* / Q000378:metabolism; D006728:Hormones / Q000032:analysis* / Q000097:blood / Q000235:genetics; D007265:Inhibins / Q000097:blood; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000235:genetics; D007335:Insulin-Like Growth Factor II / Q000032:analysis / Q000235:genetics; D007986:Luteinizing Hormone / Q000097:blood; D008969:Molecular Sequence Data; D006080:Ovarian Follicle / Q000737:chemistry / Q000166:cytology / Q000378:metabolism; D010053:Ovary / Q000737:chemistry* / Q000166:cytology / Q000378:metabolism; D010060:Ovulation / Q000502:physiology*; D011374:Progesterone / Q000032:analysis / Q000097:blood / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D011863:Radioimmunoassay; D012756:Sheep / Q000097:blood / Q000235:genetics / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D017931:DNA Primers; D006728:Hormones; D018969:Insulin-Like Growth Factor Binding Proteins; D012333:RNA, Messenger; D011374:Progesterone; D004958:Estradiol; D007265:Inhibins; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone