Expression of mRNA encoding IGF-I, IGF-II and type 1 IGF receptor in bovine ovarian follicles

Armstrong, D. G.; Gutiérrez, C. M.; Baxter, Gwen; Glazyrin, AL; Mann, G.E.; Woad, Kathryn J.; Hogg, CO; Webb, Robert I.

doi:10.1677/joe.0.1650101

Cited by 93 publications

(71 citation statements)

References 33 publications

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“…In this respect, the horse may differ from other species. In rodents, pigs and women, the expression of mRNA encoding IGF-I is confined to granulosa cells , and is only detectable in very low amounts in ruminant follicles (Perks et al 1999, Armstrong et al 2000. Messenger RNA encoding IGF-II was detected only in theca cells in the present study, in a spatial distribution similar to that reported in sheep, rats, pigs and cows , Armstrong et al 2000.…”

Section: Discussionsupporting

confidence: 84%

“…Growth factors, in particular the insulin-like growth factor (IGF) system, are thought to play a key role in ovarian follicular growth and atresia (Armstrong et al 2000). The IGFs have a variety of effects on follicular and luteal cells, including stimulation of steroidogenesis, via increased availability of steroid precursors and upregulation of steroidogenic enzyme expression and activity.…”

Section: Introductionmentioning

confidence: 99%

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Insulin-like growth factors-I and -II and insulin-like growth factor-binding protein-2 in dominant equine follicles during spring transition and the ovulatory season

Watson

Bae²,

Thomassen³

et al. 2004

Reproduction

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The period between seasonal anoestrus and cyclicity is characterized in many mares by cyclical growth and regression of large dominant follicles. The insulin-like growth factor (IGF) system plays a key role in follicular growth and regression; therefore, we hypothesized that changes in the IGF system and its binding proteins would modulate onset of cyclicity in mares. Ovaries were obtained from pony mares on the day after detection of an actively growing 30 mm transitional anovulatory follicle, and also at the second or third oestrus of the breeding season on the day after the preovulatory follicle reached 30 mm in diameter. Size of dominant follicles at the time of removal was similar in transition (32 6 0.8 mm) and at oestrus (34 6 0.6 mm). IGF-I mRNA was present in granulosa cells, with low thecal expression, whereas IGF-II mRNA was confined to the theca layer. Expression of IGF-I and -II mRNAs, and intrafollicular concentrations of oestradiol, were lower (P < 0.01; paired t test) in transitional anovulatory follicles than in preovulatory follicles. Messenger RNA encoding IGFBP-2 was present in both theca and granulosa layers. Steady-state concentrations of mRNA encoding IGFBP-2 mRNA increased (P < 0.001) in theca in preovulatory follicles. Intrafollicular concentrations of IGFBP-2 were higher (P < 0.001) in transitional than in preovulatory follicles. The similarity in circulating concentrations of IGF-I in transitional and cyclic mares, suggested that the somatotrophic axis is not involved in transition from anovulatory to ovulatory cycles. The results suggest that the increased expression of IGF-I and -II mRNAs in preovulatory follicles, along with the decrease in IGFBP-2 concentrations, could increase the bioavailability of intrafollicular IGF in large follicles during the breeding season, and support our hypothesis that intrafollicular IGF bioavailability must exceed a threshold level before ovulation can occur.

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Section: Discussionsupporting

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Insulin-like growth factors-I and -II and insulin-like growth factor-binding protein-2 in dominant equine follicles during spring transition and the ovulatory season

Watson

Bae²,

Thomassen³

et al. 2004

Reproduction

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“…Stimulatory effect of IGF-1 on oocyte maturation and further embryo development is well established [14,20]. Also, it has been established that IGF-1 has a beneficial effect on oocyte nuclear maturation [21,22], whereas, oocyte expresses IGF-1 receptor [23]. Forthermore, IGF-1 stimulates resumption of meiosis and completion of nuclear maturation of porcine oocytes [24].…”

Section: Discussionmentioning

confidence: 99%

Unexpected detrimental effect of Insulin like growth factor-1 on bovine oocyte developmental competence under heat stress

Zhandi

Towhidi

Nasr-Esfahani

et al. 2009

J Assist Reprod Genet

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Purpose To investigate the effects of Insulin like growth factor-1 (IGF-1) on bovine oocyte developmental competence under heat stress. Methods In Experiment 1, bovine cumulus-oocyte complexes (COCs) were cultured at 38.5 or 41°C for the first 12 h of maturation in the presence of either 100 ng/ml human recombinant (hr)-IGF-1 or acetic acid. In Experiment 2, COCs were cultured in 38.5 or 41°C for the first 12 h of maturation in the presence either of 100 ng/ml hr-IGF-1 or acetic acid. After fertilization, putative zygotes were cultured for 8 days.Results In experiment 1, addition of rh-IGF-1 to maturation medium at 38.5°C significantly increased the proportion of M II oocytes and decreased the percentage of TUNEL-positive oocytes compared to the other groups. However, addition of rh-IGF-1 to maturation medium under heat stress increased the percentage of TUNEL-positive oocytes. In experiment 2, addition of rh-IGF-1 under heat sress did not affect cleavage rate, whereas, blastocyst formation rate decreased in heatstressed and heat-stressed plus rh-IGF-1 groups. Similarly, The number of trophectoderm cells and total cell number were decreased in heat-stressed and heat-stressed plus rh-IGF-1 groups and the percentage of TUNEL-positive nuclei were increased in heat-stressed and heat-stressed plus rh-IGF-1 groups compared to the other groups. Conclusion The results of the present study demonstrate that IGF-1 decreases oocyte developmental competence and total cell number and increases TUNEL-positive nuclei at heat stress condition. These unexpected results of IGF-1 during maturation period under heat stress condition warrant further optimizations and investigations.

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“…A study in cattle found no difference in the expression of IGF-I receptor mRNA between small, medium and large follicles (Armstrong et al 2000). In contrast, another study found that mRNA expression of IGF-I receptor was higher in granulosa cells from follicles 8 to 10 mm than from follicles 5 to 7 mm .…”

Section: Receptorsmentioning

confidence: 91%

Follicle selection in cattle and horses: role of intrafollicular factors

Beg¹,

Ginther²

2006

Reproduction

143

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The eminent event in follicle selection during a follicular wave in monovular species is diameter deviation, wherein one follicle continues to grow (developing dominant) and other follicles (subordinates) begin to regress. In cattle, the IGF system, oestradiol and LH receptors are involved in the intrafollicular events initiating deviation as indicated by the following: (1) concentrations of free IGF-I and oestradiol in the follicular fluid and number of LH receptors in the follicular wall increase more dramatically in the future dominant follicle than in the future subordinate follicles before the beginning of deviation and (2) ablation of the largest follicle (LF) or injection of recombinant human IGF (rhIGF)-I into the second LF at the expected beginning of deviation increases the concentrations of oestradiol in second LF before the expected beginning of deviation between second LF and third LF. In horses, an increase in free IGF-I, oestradiol, inhibin-A and activin-A is greater in the future dominant follicle than in other follicles before the beginning of deviation. However, free IGF-I is the only one of these four factors needed for the initiation of deviation in horses as indicated by the following: (1) ablation of LF at the expected beginning of deviation increases the concentrations of free IGF-I in second LF before the beginning of deviation between second LF and third LF but does not increase the other factors; (2) injection of rhIGF-I into second LF at the expected beginning of deviation causes second LF to continue to grow and become a codominant follicle and (3) injection of IGF-binding protein-3 into LF at the expected beginning of deviation causes LF to regress and second LF to become dominant. Thus, the dramatic changes in the IGF system in LF compared to other follicles before the beginning of deviation play a crucial role in the events that lead to the beginning of diameter deviation in both cattle and horses. Oestradiol and LH receptors also play a role in cattle. These intrafollicular events prepare the selected follicle for the decreasing availability of FSH and increasing availability of LH. The other follicles of the wave have the same future capability but do not have adequate time to attain a similar preparatory stage.

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Expression of mRNA encoding IGF-I, IGF-II and type 1 IGF receptor in bovine ovarian follicles

Abstract: IGFs regulate gonadotrophin-stimulated proliferation and differentiation of granulosa and theca cells in vitro.

Cited by 93 publications

References 33 publications

Insulin-like growth factors-I and -II and insulin-like growth factor-binding protein-2 in dominant equine follicles during spring transition and the ovulatory season

Insulin-like growth factors-I and -II and insulin-like growth factor-binding protein-2 in dominant equine follicles during spring transition and the ovulatory season

Unexpected detrimental effect of Insulin like growth factor-1 on bovine oocyte developmental competence under heat stress

Follicle selection in cattle and horses: role of intrafollicular factors

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