Differential expression of CART in ewes with differing ovulation rates

Abstract

We hypothesised that cocaine- and amphetamine-regulated transcript () would be differentially expressed in ewes with differing ovulation rates. Expression of mRNA for , as well as, , and was determined in antral follicles ≥1 mm in diameter collected during the follicular phase in ewes heterozygous for the Booroola and Inverdale genes (I+B+; average ovulation rate 4) and ++ contemporaries (++; average ovulation rate 1.8). In ++ ewes ( = 6), was expressed in small follicles (1 to<3 mm diameter), where 18.8 ± 2.5% follicles expressed CART peptide was also detected in follicular fluid of some follicles of ++ ewes. In I+B+ ewes, 5/6 ewes did not have any follicles that expressed, and no CART peptide was detected in any follicle examined. Expression pattern of differed between I+B+ and ++ ewes with an increased percentage of small and medium follicles (3 to<4.5 mm diameter) but decreased percentage of large follicles (≥4.5 mm diameter) expressing in the I+B+ ewes. Many of the large follicles from the I+B+ ewes appeared non-functional and expression of, , and was less than that observed in ++ ewes. Expression of and was not different between groups in small and medium follicles, but expression was approximately double in I+B+ ewes compared to that in ++ ewes. Thus, ewes with high ovulation rates had a distinct pattern of expression of mRNA and protein compared to ewes with normal ovulation rates, providing evidence for CART being important in the regulation of ovulation rate.

Expression and localisation of FSHR, GHR and LHR in different tissues and reproductive organs of female yaks

“…In addition, the expression of GHR was not correlated with the change of insulin-like growth factor (IGF-I) concentration postpartum in the liver [20]. FSHR has significance regarding the modulation of animal reproductive functions [10,23]. Moreover, previous studies found that the FSH could accelerate the maturation rate of sheep oocytes and reduce their apoptosis rate, increase the expression levels of FSHR, LHR and gonadotropin releasing hormone receptor (GnRHR) mRNAs, and strengthen expressions of FSHR and GnRHR proteins [21].…”

Quantitative expression of mRNA encoding BMP/SMAD signalling genes in the ovaries of Booroola carrier and non‐carrier GMM sheep

“…McNatty et al () suggested that the differences in the hormone profile may be attributed due to the effect of FecB genotypes before and after the puberty, ovarian follicular development, gonadotrophin secretion and the pituitary response to gonadotropin‐releasing hormone (GnRH). A recent study also showed a similar progesterone concentration in heterozygous Inverdale/Booroola (I+B+) and non‐carrier genotypes before and after 12 hr of initiation of follicular phase (Juengel et al, ). Thus, it is inferred from the above discussion that the effect of FecB mutation on progesterone secretion in carrier and non‐carrier ewes is not so noticeable.…”

The local regulation of folliculogenesis by members of the transforming growth factor superfamily and its relevance for advanced breeding programmes

“…This has been observed when examining the mRNA encoding LHCGR or the ability of the cells to bind and respond to LH, as assessed by cAMP production (McNatty et al, , 2017Crawford et al, 2011;Juengel et al, 2017). Similarly, in cows carrying a copy of the Trio mutation, which have increased expression of mRNA encoding the inhibitory SMAD6 (Kamalludin et al, 2018), thus postulated reduced BMP signalling, follicles have an earlier responsiveness to LH with increased expression of the LHR in the granulosa cells (Garcia-Guerra et al, 2018a).…”

“…FSH responsiveness, as measured by mRNA encoding FSHR or the ability of the cells to bind and respond to FSH in general, is not different between control ewes and ewes carrying the Inverdale and/or Booroola mutations (McNatty et al, , 2017Crawford et al, 2011;Juengel et al, 2017). Similarly, cows carrying the Trio mutation do not have differential expression of FSHR mRNA compared to non-carrier controls (Garcia-Guerra et al, 2018a).…”

“…Granulosa cells collected from small follicles of homozygous Booroola ewes were more responsive to FSH when assessed by stimulation of oestradiol production (Campbell et al, 2006). However, it is known that the onset of CYP19A1 mRNA expression and thus aromatase activity occurs at a smaller follicular diameter in ewes carrying the Booroola mutation than their wild-type contemporaries (McNatty et al, 1985;Juengel et al, 2017). Thus the observed difference in oestradiol response is likely related to increased amounts of aromatase.…”