Immunoassay of gonadotrophin-releasing hormone in brain tissue of Booroola Merino ewes

Gale, Jean S.; Smith, Peter; Truman, Penelope; McNatty, Kenneth P.

doi:10.1530/jrf.0.0820581

Cited by 11 publications

(6 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…anticipated that the GnRH pulse frequency would be higher than in ovary-intact sheep so that if there were any underlying differences between the genotypes in GnRH secretion, these would have been more obvious than in ovary-intact ewes. In previous studies of intact or ovariectomized BB and ++ ewes no differences between the genotypes were noted in the GnRH contents in hypothalamic tissue or in the receptor binding characteristics in pituitary homogenates (Gale et al, 1988;Fleming et al, 1990). Moreover, the mean plasma concen¬ trations of i-or b-FSH in BB animals are not always different from those in ++ ewes on individual sampling days (McNatty et al, , 1989a(McNatty et al, , b, 1992bD.…”

Section: Discussionmentioning

confidence: 87%

Gonadotrophin-releasing hormone and the control of ovulation rate by the FecB gene in Booroola ewes

McNatty¹,

Hudson²,

S³

et al. 1993

Reproduction

Self Cite

View full text Add to dashboard Cite

Booroola sheep carry a FecB gene that confers high fecundity. The aims of the present studies were to determine in homozygous carriers (BB) and non-carriers (++) of the Booroola FecB gene whether there are FecB differences in the secretory characteristics of GnRH in hypophyseal-portal blood of ovariectomized ewes (Expt 1) and whether differences in ovulation rate would occur following the administration of PMSG and pulsatile GnRH to ovary-intact Booroola ewes with hypothalamic-pituitary disconnection (HPD) (Expt 2). In Expt 1, no FecB gene-specific differences were noted for GnRH with respect to pulse frequency, pulse amplitude or overall secretion rate. Irrespective of genotype there were 1.9 +/- 0.2 GnRH pulses h-1 (n = 20 ewes; 10 BB and 10 ++ animals) and 1.9 +/- 0.1 pulses of immunoreactive (i) LH h-1. In Expt 2, ovulation was induced in the HPD ovary-intact animals on three occasions (e.g. 56, 393 and 423 days after HPD surgery) using a PMSG (200 or 400 iu)-GnRH pulse (250 ng i.v. for 96 h)-GnRH bolus (10 micrograms i.v.) regimen after pretreating the animals with GnRH pulses (250 ng i.v. for 14 days). On all occasions the ovulation rates were significantly higher (P < 0.05) in BB ewes (n = 6 or 7) than in ++ animals (n = 7). No differences between the genotypes were noted with respect to the mean concentrations of progesterone in plasma notwithstanding the differences in ovulation rates.(ABSTRACT TRUNCATED AT 250 WORDS)

show abstract

Section: Discussionmentioning

confidence: 87%

Gonadotrophin-releasing hormone and the control of ovulation rate by the FecB gene in Booroola ewes

McNatty¹,

Hudson²,

S³

et al. 1993

Reproduction

Self Cite

View full text Add to dashboard Cite

show abstract

“…The in¬ crease in gonadotrophin release does not appear to be related to changes in either the concentration of gonadotrophin-releasing hormone (GnRH) in the hypothalamus (Gale, Smith, Truman & McNatty, 1988) or the binding characteristics of pituitary that the concentrations of bio-or immunoreactive inhibin in granulosa cell cultures in vitro and in follicular fluid or ovarian or peripheral venous plasma are similar for 4-+ and BB ewes.…”

mentioning

confidence: 99%

Expression of the genes for α inhibin, βA inhibin and follistatin in the ovaries of Booroola ewes which were homozygotes or non-carriers of the fecundity gene FecB

Fleming¹,

Tisdall²,

Greenwood³

et al. 1992

Journal of Molecular Endocrinology

Self Cite

View full text Add to dashboard Cite

Ovine cDNA probes for the alpha and beta A inhibin subunits and for follistatin were used to investigate the mRNA species for these hormones in ovaries obtained during the luteal phase of the oestrous cycle, from Booroola ewes which were homozygous carriers (BB) or non-carriers (++) of the FecB gene. BB ewes had significantly higher concentrations of peripheral FSH and LH immunoreactivity than ++ ewes, but the peripheral inhibin immunoreactivity and ovarian inhibin and progesterone secretion rates were not significantly different between genotypes. No gene-specific differences in the number or size of mRNA transcripts detected by Northern blotting were noted for any of these genes. A single alpha inhibin mRNA species at 1.5 kb was observed in the follicle RNA from ++ and BB ovaries. Low amounts of alpha inhibin hybridization were discerned occasionally in ++ and BB stroma and also in BB, but not in ++, corpora lutea. The beta A inhibin gene was expressed only in the follicles from both ++ and BB ovaries. At least three beta A inhibin transcripts were observed; one at 7.5 kb and at least two between 1.4 and 5.0 kb. The follistatin cDNA probe detected two major transcripts at 2.7 and 1.5 kb and a minor band at 0.5 kb in both follicle and corpora lutea RNA. Densitometry of the Northern blots revealed no significant gene-specific differences in the levels of alpha inhibin and follistatin gene mRNA transcripts.(ABSTRACT TRUNCATED AT 250 WORDS)

show abstract

“…(2) have shown that the pituitary responsiveness to exogenous gonadotrophin-releasing hormone (GnRH) is significantly lower in intact FF than + + ewes, with F + animals having an intermediate response. However, this decrease in responsiveness of the pituitaries of the F gene carriers is not associated with any increase in the hypothalamic tissue concentrations of GnRH in these animals ( 5 ) .…”

mentioning

confidence: 73%

Pituitary Binding Sites for Gonadotrophin‐Releasing Hormone in Booroola Merino Ewes which were Non‐Carriers or Homozygotes of the Fecundity Gene F

Fleming

Lun

Smith

et al. 1990

J Neuroendocrinology

Self Cite

View full text Add to dashboard Cite

Pituitary binding sites for gonadotrophin-releasing hormone (GnRH) were examined in Booroola ewes on Days 4 and 12 of the oestrous cycle and more than 12 months after ovariectomy. No significant differences were observed in the affinity of the binding sites for [lZ51]D Ala6, des Gly" GnRH ethylamide, in non-carriers ( + + ) or homozygotes of the fecundity gene (FF), in intact or ovariectomized animals (overall Ka=(1.8f0.1) x lo9 M-'; mean+SEM, n=67). In + + ewes, the number of GnRH binding sites on Day 4 of the oestrous cycle (0.199f0.025 fmol/mg pituitary, n=8) was significantly greater (P<0.05) than on Day 12 (0.107k0.012 fmol/mg pituitary, n=12). In contrast in FF ewes the number of binding sites on Days 4 and 12 were similar (Day 4: 0.119k0.030, n=8; Day 12: 0.092k0.014, n=10). On Day 4, but not Day 12, the binding site numbers were significantly higher in + + compared with FF pituitaries (P<0.05). Likewise on Day 4, but not Day 12, the plasma concentrations of follicle-stimulating hormone were significantly higher (P<0.005) in FF (1.60f0.15 nglml) than + + ewes (0.96f0.10 ng/ml). After ovariectomy, no gene-specific differences in binding site numbers were noted despite significantly higher plasma follicle-stimulating hormone concentrations in FF animals. No gene-specific differences in plasma luteinizing hormone concentrations were observed in these animals on Days 4 or 12, or after ovariectomy. Moreover, luteal phase plasma progesterone concentrations were also similar between + + and FF ewes.We conclude that the gene-specific differences in pituitary responsiveness to GnRH and in pituitary gonadotrophin output are unlikely to be due to differences in GnRH receptor binding affinities.

show abstract

Immunoassay of gonadotrophin-releasing hormone in brain tissue of Booroola Merino ewes

Cited by 11 publications

References 22 publications

Gonadotrophin-releasing hormone and the control of ovulation rate by the FecB gene in Booroola ewes

Gonadotrophin-releasing hormone and the control of ovulation rate by the FecB gene in Booroola ewes

Expression of the genes for α inhibin, βA inhibin and follistatin in the ovaries of Booroola ewes which were homozygotes or non-carriers of the fecundity gene FecB

Pituitary Binding Sites for Gonadotrophin‐Releasing Hormone in Booroola Merino Ewes which were Non‐Carriers or Homozygotes of the Fecundity Gene F

Contact Info

Product

Resources

About