The neuroendocrine events during the ovine growth-promoted maturation: The developmental importance of hypophysiotrophic action of somatostatin in ewes

Wańkowska, Marta; Romanowicz, Katarzyna; Polkowska, Jolanta

doi:10.1016/j.anireprosci.2007.12.007

Cited by 13 publications

(11 citation statements)

References 33 publications

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“…Then, these wells were frozen at -20°C until analysis. Plasma GH concentration was determined in duplicate by radioimmunoassay, considering as reference 0.68ng/mL (Wankowska et al, 2008).…”

Section: Methodsmentioning

confidence: 99%

Influence of feeding differentiation on the age at onset of puberty in Brazilian Bergamasca dairy ewe lambs

Dantas

Siqueira

Fernandes

et al. 2016

Arq. Bras. Med. Vet. Zootec.

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The objective of the study was to evaluate body growth and age at onset of puberty on lambs fed two specific diets for low and high growth rates. A herd of 20 Brazilian Bergamasca lambs was divided in two groups (n= 10) and kept confined throughout the experimental period, two animals of the same treatment/pen. Two phases were established: Phase 1, from 90 days of age until the onset of puberty; and Phase 2, from puberty onset up to 1 year old. For Phase 1, two distinct diets were formulated, being: Treatment A, which was formulated to obtain an average daily gain of approximately 150g; and Treatment B, for an average daily gain of about 250g. In Phase 2, a balanced, equal diet was provided to both groups. Every 14 days, the animals were weighed and given average daily gain, average daily dry matter intake and body condition score. From the 5 th month of age on, in each group, a vasectomized male was used to detect estrus, establishing age at puberty onset and estrus interval for each lamb. Blood samples were collected every 28 days to determine plasma growth hormone concentration. Treatment B lambs gained more weight and had higher body condition score (P<0.05) and there was no difference for age at puberty onset and plasma growth hormone levels (P>0.05) between treatments. It was found that both treatments showed satisfactory performances. Thus, treatment A may be indicated as a reasonable feeding system to achieve positive responses on confined ewe lambs during growth phase.

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Section: Methodsmentioning

confidence: 99%

Influence of feeding differentiation on the age at onset of puberty in Brazilian Bergamasca dairy ewe lambs

Dantas

Siqueira

Fernandes

et al. 2016

Arq. Bras. Med. Vet. Zootec.

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“…Functional development of the sheep somatotropic axis is completed after about 12 weeks of age and is independent of the photoperiod (Wańkowska et al 2008b). In female lambs GH secretion decreases from early to late infancy (5-12 weeks of life).…”

Section: Somatotropic Axis Secretory Activity During Growthmentioning

confidence: 99%

“…Somatostatin becomes the main factor regulating GH secretion during transition from early to middle infancy (from 5 to 9 weeks of age) . Strong, inhibiting impact of somatostatin lasts to the 22 week of the lambs life and leads to diminished GH release (Wańkowska et al 2008b). The mode of action of gonadal factors on GH secretion in lambs is through the suppressive effect of somatostatin, and this action decreases at the beginning of the juvenile period .…”

Section: Somatotropic Axis Secretory Activity During Growthmentioning

confidence: 99%

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The impact of the mother on the hypothalamic-pituit aryadrenal, hypothalamic-pituit ary-gonadal and somatotropic axes activity of offspring during postnatal ontogeny

Chmielewska

Wańkowska

2015

Acta Biologica

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The impacT of The moTher on The hypoThalamic-piTuiTary-adrenal, hypoThalamic-piTuiTary-gonadal and somaToTropic axes acTiviTy of offspring during posTnaTal onTogeny abstract During the rearing period, most of the physiological processes of offspring are under maternal regulation, which overcomes the influence of external environmental factors. Maternal deprivation activates the hypothalamic-pituitary-adrenal (HPA) axis of young mammal which in turn causes the adaptation of the developing organism to the new circumstances. It is considered that too early interruption of the mother-offspring ties may activate the not fully developed HPA axis and change the functions of the other hormonal systems of growing mammals. This article reviews the changes in the activity of the somatotropic and gonadotropic axes in young rodents and sheep during the physiological condition known as a rearing period and after maternal separation which is thought to be a stressful event in animal ontogeny. Furthermore, the current review also focus on the changes of the HPA axis hormone secretion of offspring caused by maternal deprivation.

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“…The weaning period is thought to be not static but shift for the postnatal development of gonadotrophic functions [11]. In this regard, the neuroenocrine infantile/prepubertal transition corresponds with the period when growth maturation is ending and sexual maturation is beginning, as was previously described for sheep [12,13]. Weaning is associated with a rupture of the mammalian mother-young social bond and, if abrupt, results in the stress of maternal deprivation, i.e.…”

Section: Introductionmentioning

confidence: 99%

Effect of maternal deprivation on the gonadotrophin-releasing hormone (GnRH) and GnRH-associated peptide neurobiology in lambs during the transition from infancy to prepuberty.

Wańkowska

Polkowska²

2010

Folia Histochem Cytobiol.

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Using morphological criteria we describe the effect of maternal deprivation on the gonadotrophin-releasing hormone (GnRH) and GnRH-associated peptide (GAP) of the GnRH prohormone (proGnRH) in the preoptic area (POA)-hypothalamus during the weaning period. The immunohistochemical GnRH-and GAP-neuroanatomy was investigated in female 12-week-old weanling and maternally deprived lambs and 15-week-old weaned lambs. The GnRH-immunoreactive (ir) nerve elements in the POA were more numerous in weanling and weaned lambs in comparison with maternally deprived lambs, whereas the nerve elements ir for GAP were numerous in weanlings and scarce in remaining lambs. In the hypothalamus, GnRH-ir fibers were more numerous in weaned lambs in comparison with others. Immunoreactive GnRH in the median eminence was scarce in weanlings and comparable greater in maternally deprived and weaned lambs. In contrast to ir GnRH, the GAP-ir fibers and nerve terminals in the hypothalamus and median eminence were numerous in weanlings and maternally deprived lambs and scarce in weaned lambs. In conclusion, maternal deprivation affects the intraneuronal locations involved in the maturation of GnRH from proGnRH in the POA-hypothalamus of weanlings. The described effect involves the increase in the GnRH posttranslational processing and terminal accumulation in the median eminence, which reflects the maturational increase from the low infantile terminal storage to the high prepubertal one.

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The neuroendocrine events during the ovine growth-promoted maturation: The developmental importance of hypophysiotrophic action of somatostatin in ewes

Cited by 13 publications

References 33 publications

Influence of feeding differentiation on the age at onset of puberty in Brazilian Bergamasca dairy ewe lambs

Influence of feeding differentiation on the age at onset of puberty in Brazilian Bergamasca dairy ewe lambs

The impact of the mother on the hypothalamic-pituit aryadrenal, hypothalamic-pituit ary-gonadal and somatotropic axes activity of offspring during postnatal ontogeny

Effect of maternal deprivation on the gonadotrophin-releasing hormone (GnRH) and GnRH-associated peptide neurobiology in lambs during the transition from infancy to prepuberty.

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