Measurement of inhibin-A (   A dimer) during the oestrous cycle, after manipulation of ovarian activity and during pregnancy in ewes

Knight, P. G.; Feist, Simon A.; Tannetta, Dionne; Bleach, E.C.L.; Fowler, Paul A.; O’Brien, Martin; Groome, Nigel P.

doi:10.1530/jrf.0.1130159

Cited by 54 publications

(52 citation statements)

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“…Henderson & Franchimont 1981). This conclusion is consistent with data from rats (see Introduction), and is in accord with the negative-feedback relationship between FSH and dimeric inhibin-A (Knight et al 1998).…”

Section: Discussionsupporting

confidence: 92%

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Effect of FSH and cell localization on dimeric inhibin-A secretion from bovine granulosa cells in culture

Boudjemaa

Rouillier²,

Bhatia³

et al. 2000

Journal of Endocrinology

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We tested the hypotheses that the secretion of dimeric inhibin-A from cultured bovine granulosa cells is stimulated by FSH, and that antral cells secrete more inhibin-A than do mural cells. Cells from the antral or mural compartment of follicles were cultured in defined medium in two culture systems, and dimeric inhibin-A was measured by two-site ELISA or by Western immunoblotting. In the first culture system, dimeric inhibin-A secretion declined with time in culture, but was significantly (P<0·05) higher from antral than from mural cells (as was total inhibin-measured by RIA). The secretion of dimeric inhibin-A and inhibin-from antral but not mural cells was responsive to FSH. In the second culture system, dimeric inhibin-A secretion increased with time in culture, and was significantly stimulated by FSH, but FSH responsiveness was dependent on the concentrations of insulin in the culture medium. The major forms of inhibin-A secreted had molecular masses of approximately 58, 62, 103-116 and >116 kDa; the 32 kDa form was barely detectable. These different forms were all stimulated by FSH, but the >116 and 62 kDa forms were most responsive to FSH. We conclude that (i) FSH stimulates dimeric inhibin-A secretion from bovine granulosa cells, (ii) the 62 kDa form of inhibin-A may be more responsive to FSH than the 58 kDa form, and (iii) the spatial differentiation of granulosa cell function within the follicle previously observed for oestradiol secretion was also observed for inhibin-and dimeric inhibin-A secretion.

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Section: Discussionsupporting

confidence: 92%

“…In addition, there are two distinct -subunits, termed A and B, which give rise to two dimeric inhibin populations, inhibin-A and inhibin-B (Ying 1988). In ruminants, however, inhibin-B has never been isolated from follicular fluid and assays for inhibin-B do not detect this inhibin form in sheep follicular fluid (Knight et al 1998).…”

Section: Introductionmentioning

confidence: 99%

Effect of FSH and cell localization on dimeric inhibin-A secretion from bovine granulosa cells in culture

Boudjemaa

Rouillier²,

Bhatia³

et al. 2000

Journal of Endocrinology

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“…The limit of detection was 0.2 pg/ml and intra-and interassay CV were !11%. Inhibin A was measured by ELISA as previously described (Knight et al 1998, McNeilly et al 2002. Assay sensitivity was w30 pg/ml and intra-and interassay CV were !10%.…”

Section: Hormone Assaysmentioning

confidence: 99%

Homozygosity for a single base-pair mutation in the oocyte-specific GDF9 gene results in sterility in Thoka sheep

Nicol

Bishop²,

Pong‐Wong³

et al. 2009

Reproduction

139

116

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The control of fecundity is critical in determining mammalian offspring survival. It is regulated principally by the ovulation rate, so that primates and large farm species commonly have a single offspring. Previously, several mutations have been identified in sheep which increase the naturally low ovulation rate; although in some cases homozygous ewes are infertile. In the present study we present a detailed characterization of a novel mutation in growth differentiation factor 9 (GDF9), found in Icelandic Thoka sheep. This mutation is a single base change (A1279C) resulting in a nonconservative amino acid change (S109R) in the C-terminus of the mature GDF9 protein, which is normally expressed in oocytes at all stages of development. Genotyping all animals for which reproductive records were available confirmed this mutation to be associated with increased fecundity in heterozygous ewes and infertility in homozygotes. Analysis of homozygote ovarian morphology and a number of genes normally activated in growing follicles showed that GDF9 was not involved in oocyte activation, but in subsequent development of the follicle. This study highlights the importance of oocyte factors in regulating fertility and provides new information for structural analysis and investigation of the potentially important sites of dimerization or translational modifications required to produce biologically active GDF9. It also provides the basis for the utilization of these animals to enhance sheep production.

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“…The ELISA for inhibin A designed specifically for sheep was first described by O'Brien et al (1996) and the method and specificity of the ELISA for inhibin A is described in more detail by Knight et al (1998). In brief, the ELISA is based on the use of an immobilized monoclonal antibody (E4) raised against synthetic peptides corresponding to the amino acid sequence 82-114 of the human and ovine βA subunit, and an αC-specific biotinylated monoclonal antibody (17329/H2) raised against synthetic peptides corresponding to the amino acid sequence 1-32 of the human αC subunit as detection antibody (Knight et al, 1998).…”

Section: Inhibin Elisas and Fsh And Testosterone Radioimmunoassaysmentioning

confidence: 99%

“…In brief, the ELISA is based on the use of an immobilized monoclonal antibody (E4) raised against synthetic peptides corresponding to the amino acid sequence 82-114 of the human and ovine βA subunit, and an αC-specific biotinylated monoclonal antibody (17329/H2) raised against synthetic peptides corresponding to the amino acid sequence 1-32 of the human αC subunit as detection antibody (Knight et al, 1998). Purified 32 kDa bovine inhibin A (Knight and Muttukrishna, 1994) diluted in ovariectomized ewe plasma was used as standard.…”

Section: Inhibin Elisas and Fsh And Testosterone Radioimmunoassaysmentioning

confidence: 99%

Production of inhibin A not B in rams: changes in plasma inhibin A during testis growth, and expression of inhibin/activin subunit mRNA and protein in adult testis

McNeilly

Souza²,

Baird³

et al. 2002

Reproduction

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Previous studies have shown that changes in the plasma concentrations of immunoreactive inhibin measured by radioimmunoassay occur in parallel with growth and regression of the testes during a reproductive cycle in adult Soay rams induced by exposure to an artificial lighting regimen of alternating 16 week periods of long days and short days. With the development of new two-site ELISAs for sheep inhibin A and inhibin B, we have re-examined the relationship between FSH and dimeric, biologically active inhibin in the reproductive cycle in adult Soay rams. No signal was generated by sheep testicular extract, ram or ewe plasma, or sheep ovarian follicular fluid in the inhibin B ELISA. In contrast, ram plasma contained significant activity in the inhibin A ELISA, which diluted in parallel to the inhibin A standard, and was abolished by preincubation of ram plasma with monoclonal antibodies specific for the betaA, but not the betaB, subunit. These results indicate that the ram is the first adult male mammalian species identified to date in which the testes produce and secrete dimeric inhibin A and not inhibin B. Northern blot analysis and immunocytochemistry confirmed the presence of alpha, betaA and betaB inhibin/activin subunit mRNA and protein in the testes of adult rams. Changes in plasma inhibin A concentrations occurred in parallel with the growth and regression of the testes during the long day: short day: long day lighting regimen in adult Soay rams, confirming our previous observations with immunoreactive inhibin. During the growth phase of the testes in the first 8 weeks of exposure to short days there was a positive correlation between plasma FSH and inhibin A concentrations, indicating that during this phase the secretion of inhibin A is stimulated by FSH and that inhibin A did not act as a negative feedback hormone on FSH secretion. From week 8.5 to week 16.0 of exposure to short days, there was a negative correlation between FSH and testosterone concentrations, but not inhibin, indicating that when inhibin concentrations are high, testosterone acts as the negative regulator of FSH secretion. Thus, in intact adult rams, when the testes are fully active it appears that inhibin A may sensitize the pituitary to the negative feedback effects of testosterone, at which time they act synergistically to maintain plasma concentrations of FSH.

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Measurement of inhibin-A ( A dimer) during the oestrous cycle, after manipulation of ovarian activity and during pregnancy in ewes

Abstract: of FSH, LH, oestradiol and progesterone were determined by radioimmunoassay.

Cited by 54 publications

References 1 publication

Effect of FSH and cell localization on dimeric inhibin-A secretion from bovine granulosa cells in culture

Effect of FSH and cell localization on dimeric inhibin-A secretion from bovine granulosa cells in culture

Homozygosity for a single base-pair mutation in the oocyte-specific GDF9 gene results in sterility in Thoka sheep

Production of inhibin A not B in rams: changes in plasma inhibin A during testis growth, and expression of inhibin/activin subunit mRNA and protein in adult testis

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