Ovulation mechanism in South American Camelids: The active role of β-NGF as the chemical signal eliciting ovulation in llamas and alpacas

Silva, Mauricio; Paiva, Luis; Ratto, M.H.

doi:10.1016/j.theriogenology.2020.01.078

Cited by 17 publications

(14 citation statements)

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“…Neurotrophins, including β-NGF, are classically known for their role in neural growth and survival (24), but the relatively recent isolation and purification of β-NGF from the seminal plasma of llamas (17,18) and also other species (25) has led to revisiting their roles in reproductive biology, emerging new ones (18,26). Previous studies have linked NGF to ovarian development and innervation (27)(28)(29), but in the last years, evidence (1) indicates that β-NGF is involved in CL formation.…”

Section: Discussionmentioning

confidence: 99%

“…It is now well-established that the beta-nerve growth factor (β-NGF) present in the seminal plasma of llamas and alpacas is the essential signal inducing the luteinizing hormone (LH) surge and ovulation in these species (1). Purified llama β-NGF also has a significant luteotrophic effect after intramuscular or intrauterine infusion in llamas and alpacas (2,3).…”

Section: Introductionmentioning

confidence: 99%

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β-NGF Stimulates Steroidogenic Enzyme and VEGFA Gene Expression, and Progesterone Secretion via ERK 1/2 Pathway in Primary Culture of Llama Granulosa Cells

et al. 2020

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P450 side-chain cleavage (P450scc/CYP11A1), steroidogenic acute regulatory protein (STAR), and 3β-hydroxysteroid dehydrogenase (HSD3B1) at 10 and 20 h of treatment. Application of the MAPK inhibitor U0126 resulted in downregulation of the genes encoding these enzymes. β-NGF also enhanced progesterone synthesis, which was prevented by the prior application of the MAPK inhibitor U0126. Finally, western blot analysis confirmed that β-NGF activates the ERK1/2 signaling pathway. In conclusion, our results indicate that β-NGF exerts direct luteotropic effects on llama ovarian tissue via the ERK 1/2 pathway.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

β-NGF Stimulates Steroidogenic Enzyme and VEGFA Gene Expression, and Progesterone Secretion via ERK 1/2 Pathway in Primary Culture of Llama Granulosa Cells

et al. 2020

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“…In the musk shrew (Suncus murinus), KISS1 expression seems to be like in spontaneous ovulators, but mating is reported as the critical cue for the activation (by means of c-Fos expression) of POA KISS1 cells (20), indicating kisspeptin cells as a potential player involved in the ovulatory mechanism. Llamas are also induced ovulators, however, in this species, ovulation occurs in response to the hormonal [but not reflex (21)] stimulus of the protein beta-nerve growth factor (β-NGF) that is present in the male seminal plasma (22,23); the resulting LH surge and ovulation have been shown to be dependent on GnRH release (24), implying the participation of a central mechanism. Although the involvement of kisspeptin in this response has been suggested (25), the organisation of kisspeptin systems and its physiological role is not clear.…”

Section: Introductionmentioning

confidence: 99%

Distribution of GnRH and Kisspeptin Immunoreactivity in the Female Llama Hypothalamus

et al. 2021

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Llamas are induced non-reflex ovulators, which ovulate in response to the hormonal stimulus of the male protein beta-nerve growth factor (β-NGF) that is present in the seminal plasma; this response is dependent on the preovulatory gonadotrophin-releasing hormone (GnRH) release from the hypothalamus. GnRH neurones are vital for reproduction, as these provide the input that controls the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the pituitary gland. However, in spontaneous ovulators, the activity of GnRH cells is regulated by kisspeptin neurones that relay the oestrogen signal arising from the periphery. Here, we investigated the organisation of GnRH and kisspeptin systems in the hypothalamus of receptive adult female llamas. We found that GnRH cells exhibiting different shapes were distributed throughout the ventral forebrain and some of these were located in proximity to blood vessels; sections of the mediobasal hypothalamus (MBH) displayed the highest number of cells. GnRH fibres were observed in both the organum vasculosum laminae terminalis (OVLT) and median eminence (ME). We also detected abundant kisspeptin fibres in the MBH and ME; kisspeptin cells were found in the arcuate nucleus (ARC), but not in rostral areas of the hypothalamus. Quantitative analysis of GnRH and kisspeptin fibres in the ME revealed a higher innervation density of kisspeptin than of GnRH fibres. The physiological significance of the anatomical findings reported here for the ovulatory mechanism in llamas is still to be determined.

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“…Moreover, studies in rats and hamsters, as well as sheep, showed an elevated level of NGF in the follicular fluid during the preovulatory phase 10,11 . Interestingly, an administration of NGF in different ways consistently induced ovulation in several induced ovulatory mammals, like llamas, camelids and alpacas [12][13][14] . In a research using a camel model, it was suggested that NGF in the seminal plasma was absorbed by the endometrium to the bloodstream and then reached to the hypothalamus where this NGF stimulated neurons to produce kisspeptin (a potent stimulator of GnRH), which eventually organized the preovulatory LH surge 12 .…”

Section: Role Of Ngf In Ovulationmentioning

confidence: 99%

A Comparative Study of Nerve Growth Factor Level in the Follicular Fluid of Polycystic and Non-Polycystic Ovary Syndrome Women Undergoing ICSI: a Cross-sectional Study

Alfatlawy¹,

Taee²,

Rahim³

2020

IJFMT

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Background : Nerve growth factor is a member of a group of proteins called Neurotrophins (NTs), which are necessary for growth and differentiation of neurons in both central and peripheral nervous systems. In addition to this essential role, NGF has been suggested to play a possible role in ovarian functions. Thus, we proposed this study to evaluate the nerve growth factor level in the follicular fluid of women with polycystic ovary syndrome undergoing Intracytoplasmic sperm injection (ICSI) in comparison with the control group (non-polycystic women).Results : Follicular fluid nerve growth factor levels of non PCOS women were significantly higher than these of PCOS group (245.399 ± 63.41pg/ml vs. 149.592 ± 64.86 pg/ml), p-value =0.0001*. Also, it was significantly correlated negatively with oocytes number (Correlation Coefficient r= -0.431, P-value = 0.01) and positively with FSH (r=0.370, p value = 0.029). Conclusion:Nerve growth factor level in the follicular fluid of polycystic ovary syndrome women is lower than it in non-PCOS ones. Additionally, it correlates directly with cycle day two FSH and inversely with oocytes number.

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Ovulation mechanism in South American Camelids: The active role of β-NGF as the chemical signal eliciting ovulation in llamas and alpacas

Cited by 17 publications

References 98 publications

β-NGF Stimulates Steroidogenic Enzyme and VEGFA Gene Expression, and Progesterone Secretion via ERK 1/2 Pathway in Primary Culture of Llama Granulosa Cells

β-NGF Stimulates Steroidogenic Enzyme and VEGFA Gene Expression, and Progesterone Secretion via ERK 1/2 Pathway in Primary Culture of Llama Granulosa Cells

Distribution of GnRH and Kisspeptin Immunoreactivity in the Female Llama Hypothalamus

A Comparative Study of Nerve Growth Factor Level in the Follicular Fluid of Polycystic and Non-Polycystic Ovary Syndrome Women Undergoing ICSI: a Cross-sectional Study

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