Regulatory Roles of Leptin at the Hypothalamic-Hypophyseal Axis Before and after Sexual Maturation in Cattle1

Zieba, D; Amstalden, M.; Morton, Sue; Maciel, Marlon Nadal; Keisler, D.H.; Williams, Gary L.

doi:10.1095/biolreprod.104.028548

Cited by 52 publications

(41 citation statements)

References 51 publications

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“…4. GnRH was secreted in the 3V CSF in a pulsatile pattern, consistent with previous reports on mature cows (Gazal et al 1998, Zieba et al 2004. High concordance in the patterns of CSF GnRH and plasma LH secretion was observed.…”

Section: Bw Gain and Circulating Concentrations Of Leptinsupporting

confidence: 90%

“…This concept is supported by observations that ovarian function is stimulated in immature female monkeys treated with GnRH (Wildt et al 1980) and in lambs treated with LH (Foster et al 1984). Our group has demonstrated that leptin has a critical permissive role in controlling pubertal maturation in heifers , Maciel et al 2004a, and this regulation occurs mainly as a result of leptin's effects on GnRH secretion (Zieba et al 2004). Nonetheless, several studies have failed to demonstrate Figure 4 Patterns of secretion of GnRH in 3V CSF and of LH in plasma of representative LG (#568 and #594) and HG heifers (#587 and #600) at 8 and 9 months of age.…”

Section: Discussionmentioning

confidence: 66%

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Reciprocal changes in leptin and NPY during nutritional acceleration of puberty in heifers

Cardoso¹,

Alves²,

Prezotto³

et al. 2014

Journal of Endocrinology

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Feeding a high-concentrate diet to heifers during the juvenile period, resulting in increased body weight (BW) gain and adiposity, leads to early-onset puberty. In this study, we tested the hypothesis that the increase in GnRH/LH release during nutritional acceleration of puberty is accompanied by reciprocal changes in circulating leptin and central release of neuropeptide Y (NPY). The heifers were weaned at 3.5 months of age and fed to gain either 0.5 (Low-gain; LG) or 1.0 kg/day (High-gain; HG) for 30 weeks. A subgroup of heifers was fitted surgically with third ventricle guide cannulas and was subjected to intensive cerebrospinal fluid (CSF) and blood sampling at 8 and 9 months of age. Mean BW was greater in HG than in LG heifers at week 6 of the experiment and remained greater thereafter. Starting at 9 months of age, the percentage of pubertal HG heifers was greater than that of LG heifers, although a replicate effect was observed. During the 6-h period in which CSF and blood were collected simultaneously, all LH pulses coincided with or shortly followed a GnRH pulse. At 8 months of age, the frequency of LH pulses was greater in the HG than in the LG group. Beginning at 6 months of age, concentrations of leptin were greater in HG than in LG heifers. At 9 months of age, concentrations of NPY in the CSF were lesser in HG heifers. These observations indicate that increased BW gain during juvenile development accelerates puberty in heifers, coincident with reciprocal changes in circulating concentrations of leptin and hypothalamic NPY release.

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Section: Bw Gain and Circulating Concentrations Of Leptinsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 66%

Reciprocal changes in leptin and NPY during nutritional acceleration of puberty in heifers

Cardoso¹,

Alves²,

Prezotto³

et al. 2014

Journal of Endocrinology

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show abstract

“…Although the precise chemical or hormonal signals that link BW and adiposity to pubertal onset have not been clearly defined, an increase in circulating concentrations of leptin, an adipose-derived hormone that regulates a wide variety of physiological processes, has been shown to precede the onset of puberty in several species, including cattle (Perry, 2012) leading to postulation that leptin acts as a permissive signal to the occurrence of puberty. Furthermore, administration of recombinant ovine leptin stimulated secretion of GnRH and LH in undernourished heifers, but was not capable of accelerating puberty onset in well-nourished heifers Zieba et al, 2004). However recent findings show that although exogenous administration of leptin temporarily enhanced the rate of follicular growth, it does not accelerate puberty (Carvalho et al, 2013).…”

Section: Suckling-maternal Bondmentioning

confidence: 94%

Optimising reproductive performance of beef cows and replacement heifers

Diskin

Kenny

2014

Animal

104

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A reproductively efficient beef cow herd is fundamental to meeting the protein and specifically, red meat demand of an ever increasing global population. However, attaining a high level of reproductive efficiency is underpinned by producers being cognisant of and achieving many key targets throughout the production cycle and requires significant technical competency. The lifetime productivity of the beef bred female commences from the onset of puberty and will be dictated by subsequent critical events including age at first calving, duration of the postpartum interval for each successive calving, conception and pregnancy rate and ultimately manifested as length of intercalving intervals and number of calves weaned over her lifetime. Puberty in heifers is a consequence of the interactive effects of genetics and both pre-and post-weaning nutrition. Early onset of puberty is essential to achieving the first main reproductive target for beef cow herds; first calving at 2 years of age. In calved heifers and mature cows, the onset of ovarian activity, postpartum is a key event dictating the calving interval. Again, this will be the product mainly of prepartum nutrition, manifested through body condition and the strength of the maternal bond between cow and calf, though there is increasing evidence of a modest genetic influence on this trait. Following the initiation of postpartum ovarian cyclicity, conception and subsequent pregnancy rate is generally a function of bull fertility in natural service herds and heat detection and timing of insemination in herds bred through artificial insemination. Cows and heifers should be maintained on a steady plane of nutrition during the breeding season, but the contribution of significant excesses or deficiencies of nutrients including protein and trace elements is likely to be minor where adequate pasture is available. While, increased efforts are being made internationally to genetically identify and select for more reproductively efficient beef cows, this is a more long-term strategy and will not replace the need for a high level of technical efficiency and management practice at farm level.

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“…This may suggest both the acute heat stress and the altered steps in the mechanism controlling the LH release to GnRH, for example, upregulated GnRH receptors on the cell surface of pituitaries in the July group. Secretion of luteinizing hormone is pulsatile in prepubertal heifers [12], and only one blood sample was collected before the GnRH injection from each heifer to evaluate the basal LH concentration in this study. Thus, further work is needed to determine the seasonal effect on pulsatile LH release in Holsteins in Hokkaido (Japan).…”

Section: Resultsmentioning

confidence: 99%

Seasonal Differences in the Parameters of Luteinizing Hormone Release to Exogenous Gonadotropin Releasing Hormone in Prepubertal Holstein Heifers in Sapporo

Kadokawa

2007

Journal of Reproduction and Development

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Abstract. Stress due to summer heat has adverse effects on reproduction in Holstein dairy cattle. Summer suppression of reproduction of Holsteins can pose an important economic problem, even in Hokkaido prefecture located in the northern region of Japan. Hokkaido is one of the most important dairy farming areas of Japan. This study is an attempt to clarify the seasonal differences in the parameters of luteinizing hormone (LH) response to exogenous gonadotropin releasing hormone (GnRH) in Sapporo, Hokkaido, Japan. A total of 12 prepubertal heifers received an injection with GnRH analogue intramuscularly in either May (n=4, May group), July (n=4, July group), or November (n=4, November group), and serial blood samples were collected to analyze the parameters of the LH response curve after GnRH injection. The parameters were as follows: the basal LH concentration, peak LH concentration, duration from the time of GnRH injection to the time of the peak LH concentration, and area under the LH response curve (AUC). There were no significant differences in the basal and peak LH concentrations or the AUC among the three groups. The July group reached the LH peak significantly (P<0.05) faster than the May group, but there was no significant difference with the November group. Therefore, the results of the present study do not demonstrate an effect of summer heat on the LH response to the exogenous GnRH in Holstein heifers.

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Regulatory Roles of Leptin at the Hypothalamic-Hypophyseal Axis Before and after Sexual Maturation in Cattle1

Cited by 52 publications

References 51 publications

Reciprocal changes in leptin and NPY during nutritional acceleration of puberty in heifers

Reciprocal changes in leptin and NPY during nutritional acceleration of puberty in heifers

Optimising reproductive performance of beef cows and replacement heifers

Seasonal Differences in the Parameters of Luteinizing Hormone Release to Exogenous Gonadotropin Releasing Hormone in Prepubertal Holstein Heifers in Sapporo

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