The insulin-like growth factor (IGF) system and gonadotropin regulation: actions and interactions

Lackey, Brett R.; Gray, Sandra L.; Henricks, D. M.

doi:10.1016/s1359-6101(99)00013-1

Cited by 58 publications

(47 citation statements)

References 144 publications

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“…The IGFs circulate monocovalently bound to large molecular weight IGFBPs [7,43]. Six binding proteins (-1 to -6) have been characterized in humans, rodents and domestic animals [5,49,77]. IGFBPs are physiological regulators of IGF actions, either stimulating or inhibiting IGF action [44].…”

Section: The Insulin-like Growth Factor Systemmentioning

confidence: 99%

“…A study in prepubertal rats, indicated that IGF-I acts on the median eminence, which contains the highest density of IGFR-I in the brain to elicit a dose-related increase in GnRH release [42]. It has also been observed in many other species, including primates, that systemic IGF-I levels increase during puberty [49]. Thus, IGF-I may represent one of the metabolic signals thought to be involved in the initiation of puberty.…”

Section: Igf-i and Hypothalamo-pituitary Functionmentioning

confidence: 99%

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Insulin-Like Growth Factor-I as a Possible Hormonal Mediator of Nutritional Regulation of Reproduction in Cattle

Zulu

Nakao

Sawamukai

2002

The Journal of Veterinary Medical Science

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ABSTRACT. The current review aims to establish insulin-like growth factor-1 (IGF-I) as the factor that signals nutritional status to the reproductive axis, and show that assessment of IGF-I in blood early postpartum during the negative energy balance (NEB) period could be used to predict both nutritional and reproductive status in dairy cattle. The review also explores the effect of nutritional status on circulating IGF-I concentrations and the endocrine role of IGF-I on the reproductive axis. IGF-I plays an important role in gonadotropininduced folliculogenesis, ovarian steroidogenesis and corpus luteum (CL) function. It also modulates pituitary and hypothalamus function. IGF-I clearly has an endocrine role on the reproductive axis. Severe under nutrition significantly reduces plasma IGF-I concentrations. During the critical period of NEB in high yielding dairy cattle early postpartum, IGF-I concentrations are low in blood and its levels are positively correlated to energy status and reproductive function during this period. Changes in circulating IGF-I immediately postpartum may help predict both nutritional and reproductive status in dairy cattle. IGF-I is therefore one of the long sought factors that signal nutritional status to the reproductive axis.

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Section: The Insulin-like Growth Factor Systemmentioning

confidence: 99%

Section: Igf-i and Hypothalamo-pituitary Functionmentioning

confidence: 99%

Insulin-Like Growth Factor-I as a Possible Hormonal Mediator of Nutritional Regulation of Reproduction in Cattle

Zulu

Nakao

Sawamukai

2002

The Journal of Veterinary Medical Science

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“…IGFs have also been implicated in stimulation of osteoclast formation and function, leading to the view that the GH/IGF system is involved in the coupling between bone resorption and bone formation (Eriksen et al 1996). In turn, the GH/IGF system has also been shown to mediate the effects of other anabolic factors such as thyroid hormones and steroids (Lackey et al 1999, Prakasam et al 1999.…”

Section: Introductionmentioning

confidence: 99%

“…Some authors reported that GH deficiency in rats, as well as in humans, is accompanied by delayed pubertal development (Bartlett et al 1990, Holmes & Shalet 1996 whereas other authors reported no significant disturbance in sexual maturation in GH-deprived rats (Gruaz et al 1994). Sex steroids increase GH secretion and synthesis as well as the production of various components of the IGF system (Lackey et al 1999). Reciprocally, IGF-I has a role in the regulation of sex steroids synthesis and metabolism (Lackey et al 1999).…”

Section: Introductionmentioning

confidence: 99%

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Long-term effects on bone of postnatal immunization against GHRH in female and male rats

Sibilia¹,

Rigamonti²,

Pagani³

et al. 2003

Journal of Endocrinology

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The effects of neonatal passive immunization against GHRH on bone was examined in male and female rats. Pups were treated subcutaneously with GHRH-antiserum (GHRH-Ab) from day 1 to day 10 of age. Bone mineral content (BMC) and bone mineral density (BMD) were evaluated at monthly intervals until 7 months. Markers of bone resorption (urinary lysylpyridinoline, LP), bone formation (serum osteocalcin, OC) and serum IGF-I were measured at 2, 3 and 7 months. In male rats, GHRH-Ab did not modify BMC and BMD when compared with controls. In contrast, female rats demonstrated lower whole body and femoral BMC and BMD from 2 to 7 months of age. Reduced bone growth in the females was associated with lower IGF-I levels than controls at 2 and 3 months of age, whereas in males IGF-I titers did not change during the period of the study. LP excretion was higher in GHRH-Ab-treated rats at 2 and 3 months in both sexes. In females, no difference in OC values was recorded, whereas in GHRH-Ab-treated males, there was an increase in OC levels at 2 and 3 months. These data indicate that transient GHRH deprivation induces an osteopenic effect in female rats which is not evident in male rats.

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“Immunolocalization and effect of low concentrations of Insulin like growth factor‐1 (IGF‐1) in the canine ovary”

Cardilli

Sousa-Oliveira

Franchi-João

et al. 2020

Veterinary Medicine & Sci

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Insulin like growth factor‐1 (IGF‐1) plays an important role in the regulation of ovarian function. Despite its extensive study in several species, there is a paucity of information about IGF‐1`s function and localization in the canine ovary. The aim of the present study was to assess the effect of IGF‐1 on oocyte nuclear maturation and to immunolocalize the IGF‐1 and its receptor (IGF‐1R) in the ovary. Cumulus‐oocyte complexes (COCs) were obtained from 34 bitches. The COCs from each bitch were incubated in TCM 199‐HEPES in the absence (n = 199) or presence (n = 204) of 100 ng/ml IGF‐1 for 96 hr at 38ºC in 5% CO2, stained and evaluated for nuclear maturation by fluorescence microscopy. The results showed that the addition of IGF‐1 did not have an effect (p ˃ 0.05) on the nuclear maturation under these conditions. The immunohistochemical study revealed nuclear and cytoplasmic staining for IGF‐1 and IGF‐1R, respectively. Both were localized in all ovarian structures including the corpus luteum, but not in the granulosa cells from primordial follicles. In addition, IGF‐1 was not localized in the oocytes in tertiary follicles. The results obtained show the presence of IGF‐1 through the stages of follicular growth and in the corpus luteum of the canine ovary. However, its role on oocyte nuclear maturation could not be demonstrated.

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The insulin-like growth factor (IGF) system and gonadotropin regulation: actions and interactions

Cited by 58 publications

References 144 publications

Insulin-Like Growth Factor-I as a Possible Hormonal Mediator of Nutritional Regulation of Reproduction in Cattle

Insulin-Like Growth Factor-I as a Possible Hormonal Mediator of Nutritional Regulation of Reproduction in Cattle

Long-term effects on bone of postnatal immunization against GHRH in female and male rats

“Immunolocalization and effect of low concentrations of Insulin like growth factor‐1 (IGF‐1) in the canine ovary”

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