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Systemic Concentrations of Endogenous and Exogenous FSH in Anoestrous Ewes Superstimulated with Folltropin ® ‐V
Author(s) -
Bartlewski PM,
Fuerst KJ,
Alexander BD,
King WA
Publication year - 2009
Publication title -
reproduction in domestic animals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.546
H-Index - 66
eISSN - 1439-0531
pISSN - 0936-6768
DOI - 10.1111/j.1439-0531.2008.01124.x
Subject(s) - medicine , endocrinology , antral follicle , follicular phase , biology , follicular fluid , estrous cycle , radioimmunoassay , follicle stimulating hormone , hormone , luteinizing hormone , zoology , andrology , oocyte , embryo , microbiology and biotechnology
Contents The synchronization of follicular waves with medroxyprogesterone acetate (MAP) and oestradiol‐17β (E 2 ‐17β) prior to ovarian superstimilation in anoestrous ewes reduces the variability in superovulatory responses by an unknown mechanism. Follicle stimulating hormone (FSH) is a primary promoter of antral follicular development, but the relevance of circulating FSH concentrations to the superovulation performance in ewes has not been examined. Eighteen anoestrous Rideau Arcott ewes (May–June) were superovulated with Folltropin ® ‐V (porcine FSH), with (n = 8; treated ewes) or without (n = 10; control ewes) a single i.m. dose of 350 μg of E 2 ‐17β, given on the sixth day of a 14‐day treatment with MAP‐releasing intravaginal sponges (60 mg). The superovulatory treatment, begun 6 days after E 2 ‐17β injection, consisted of six i.m. applications of Folltropin ® ‐V given twice daily (at 08:00 and 16:00 h), followed by an i.m. injection of GnRH (50 μg). Blood samples collected every 8 h throughout the 3‐day treatment, were analysed by radioimmunoassays for concentrations of ovine and porcine FSH, using species‐specific standards and primary antibodies. Serum concentrations of oFSH were greater (p < 0.05) in the controls compared to treated ewes at 40, 64 and 72 h and the variability in mean oFSH concentrations was greater (p < 0.05) in control ewes at 40, 48, 64 and 72 h after the 1 st Folltropin ® ‐V injection. There were no differences (p > 0.05) between the two groups in serum concentrations of pFSH. Significant correlations were recorded between the number of corpora lutea (CL) and oFSH concentrations at 8 h ( r = 0.72, p < 0.05), 16 h ( r =0.63, p < 0.05) and 64 h ( r = 0.84, p < 0.01) after the 1 st Folltropin ® ‐V injection. The total number of recovered embryos was positively correlated to oFSH concentrations at 56 h ( r = 0.69, p < 0.05). We concluded that changes in endogenous FSH concentrations during ovarian superstimulation with pFSH might contribute to the variability in superovulatory responses in ewes.