Changes in metabolites, metabolic hormones, and luteinizing hormone before puberty in Angus, Braford, Charolais, and Simmental heifers.

Jones, E J; Armstrong, Jeffrey D.; Harvey, R. W.

doi:10.2527/1991.6941607x

Cited by 59 publications

(44 citation statements)

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“…This would have resulted in a change in the ratio between IGFBP-3 and IGF-1, and suggests that variation in IGF-1: IGFBP-3 ratio could possibly mediate the time to reach puberty. Results obtained by Jones et al (1991), Granger et al (1989) and Yelich et al (1996) differ from results obtained in the present experiment in terms of association between puberty and IGF-1 concentration. These authors found that IGF-1 increased before puberty, independent of dietary treatment.…”

Section: Discussioncontrasting

confidence: 57%

The roles of the insulin-like growth factor system and leptin as possible mediators of the effects of nutritional restriction on age at puberty and compensatory growth in dairy heifers

Luna-Pinto¹,

Cronje²

2000

SA J. An. Sci.

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The aim of this experiment was to determine to what extent changes in the blood concentrations of insulinlike growth factor-1 (IGF-1), IGF binding proteins (IGFBPs), leptin and glucose are associated with compensatory growth and age at puberty in Friesian heifers. Twelve heifers (6 months old; 179.8 kg body weight) were allocated to one of two dietary treatments for 30 weeks. Treatments were designed to result in two different growth rates during the first 13 weeks of the experiment, viz. 0.3 kg/d (restriction treatment) or 0.6 kg/d (control treatment). From week 14 to 30, the restricted group received the same amount of feed per kg bodyweight as was fed to the control group (compensatory phase). Heifers in the control treatment reached puberty four weeks earlier than the restricted group. Mean body weight at puberty was 256.3 kg and was not affected by treatment. During the compensatory phase, the growth rate of the previously restricted animals was greater, and feed conversion ratio superior, compared to that of the control group. Plasma IGF-1 and IGFBP-3 concentrations were higher in the restricted group than in the control group during the early compensatory phase. Concentrations of IGFBP-3 increased and peaked at puberty for both treatments, even though puberty occurred at different ages. In contrast, concentrations of IGF-1 peaked at the point of maximum growth rate in the previously restricted animals, and in neither treatment was there a clear relationship with the age of puberty. Plasma leptin concentrations increased until puberty in both treatments even though the date of puberty differed. Plasma glucose concentration did not change at puberty for either treatment; however, differences between treatments were found after the restriction period. There were no differences in IGFBP-2 concentrations between treatments or sampling periods. It is concluded that concentrations of glucose, IGF-1 and IGFBP-3 are affected by nutritional restriction and repletion, and may contribute in some measure to the endocrine regulation of compensatory growth. It is suggested that the increased concentrations of leptin and IGFBP-3 during pubertal development may act as physiological signals for the onset of puberty.

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Section: Discussioncontrasting

confidence: 57%

The roles of the insulin-like growth factor system and leptin as possible mediators of the effects of nutritional restriction on age at puberty and compensatory growth in dairy heifers

Luna-Pinto¹,

Cronje²

2000

SA J. An. Sci.

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“…In contrast with insulin secretion, plasma IGF-I concentrations increased during the onset of puberty in Shiba goats, as shown in a variety of species such as rodents [34,35], ruminants [22,36], and primates [37,38] including humans [37][38][39][40]. IGF-I concentrations in the circulation are closely associated w ith nutritional status in both monogastric animals [21] and ruminants [22][23][24].…”

Section: Discussionmentioning

confidence: 99%

Body Growth and Plasma Concentrations of Metabolites and Metabolic Hormones during the Pubertal Period in Female Shiba Goats

Sakurai

Ohkura

Matsuyama

et al. 2004

Journal of Reproduction and Development

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Abstract.It has been shown in various species that the onset of puberty is closely associated with body growth and nutritional state rather than age. The present study was conducted to determine the timing of puberty and to clarify body growth and metabolic changes around the pubertal period in female Shiba goats. Blood samples were collected between 10 to 38 weeks of age from 12 female goats, and plasma concentrations of progesterone, metabolites (glucose, nonesterified fatty acid, ketone body and acetic acid) and metabolic hormones (insulin and insulin-like growth factor-I (IGF-I)) were analyzed. Physical parameters (body weight, withers height and body length) were also measured at the blood sampling. The week when plasma progesterone concentrations first exceeded 1.0 ng/ml was designated as the onset of puberty. The results showed that the average age of the onset of puberty was 27.0 ± 0.9 (mean ± SEM) weeks in female Shiba goats. When the goats reached puberty, the average values of body weight and goat body mass index ((body weight (kg)/withers height (cm)/body length (cm)) × 10 3 ) were 12.2 ± 0.5 kg and 5.7 ± 0.2, respectively. No particular change associated with puberty was apparent for plasma concentrations of the metabolites examined. Plasma insulin concentrations were maintained at lower levels until the onset of puberty, and then they began to gradually increase. Plasma IGF-I concentrations began to gradually increase 1 to 4 weeks before the onset of puberty and this increase continued throughout the peripubertal period. These results imply that IGF-I acts as a peripheral nutritional signal to trigger the onset of puberty in Shiba goats. Key words: Puberty, Body growth, Metabolites, IGF-I, Shiba goat (J. Reprod. Dev. 50: [197][198][199][200][201][202][203][204][205] 2004) he onset of puberty is the result of a series of complex developmental events that occur within the reproductive endocrine axis. Just before the onset, there is a high frequency rhythm of gonadotropin-releasing hormone (GnRH) secretion and a sustained rise in basal luteinizing hormone (LH) secretion as the frequency of LH pulses increases, and the follicular phase begins, leading to the first LH surge and ovulation [1]. It has also been shown in heifers that the responsiveness of the pituitary gland to GnRH [2] and the action of estrogen on LH secretion [3] also change just before puberty. Numerous studies have demonstrated a close association between body growth, nutritional status and the timing of puberty onset. In cattle [4,5], sheep [6,7] and rodents [8,9], energy deficiency retards growth and delays the onset of puberty. Several lines of evidence from earlier investigations

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“…Serum IGF-I was assayed using glycylglycine hydrochloride extraction procedures as described (24) with modifications (25,26). The standard source was recombinant human IGF-I (Amgen, Thousand Oaks, CA).…”

Section: Methodsmentioning

confidence: 99%

“…Serum INS concentrations were analyzed via the procedures of Hales and Randle (27) with modifications (26). Average intra-and inter-assay CV were 9.1 and 11.4%, respectively, for 3 assays.…”

Section: Methodsmentioning

confidence: 99%

Effect of feed restriction on serum somatotropin, insulin-like growth factor-I-(IGF-I) and IGF binding proteins in cyclic heifers actively immunized against growth hormone releasing factor

Armstrong

Cohick

Harvey

et al. 1993

Domestic Animal Endocrinology

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Changes in metabolites, metabolic hormones, and luteinizing hormone before puberty in Angus, Braford, Charolais, and Simmental heifers.

Cited by 59 publications

References 0 publications

The roles of the insulin-like growth factor system and leptin as possible mediators of the effects of nutritional restriction on age at puberty and compensatory growth in dairy heifers

The roles of the insulin-like growth factor system and leptin as possible mediators of the effects of nutritional restriction on age at puberty and compensatory growth in dairy heifers

Body Growth and Plasma Concentrations of Metabolites and Metabolic Hormones during the Pubertal Period in Female Shiba Goats

Effect of feed restriction on serum somatotropin, insulin-like growth factor-I-(IGF-I) and IGF binding proteins in cyclic heifers actively immunized against growth hormone releasing factor

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