Effects of insulin-like growth factor on nitrogen balance during hypoxic exposure

Iioka, Yoshinori; Sugito, Kazutoshi; Moriya, Tsuneo; Kuriyama, Takayuki

doi:10.1183/09031936.02.00234302

Cited by 12 publications

(12 citation statements)

References 34 publications

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“…that of IIOKA et al [12] in the current issue of this journal, are comparable to an altitude of 5,000 m with regards to the hypoxia created. To avoid effects of hypoxia-induced hypophagia, the rats studied were given total parenteral nutrition (TPN).…”

supporting

confidence: 59%

“…However, they also observed insulin resistance and reduced lipolysis. These metabolic adaptations point towards the potential adverse effects of metabolic overload by hyperalimentation under such hypoxic circumstances.The study of IIOKA et al [12] shows that rh insulinlike growth factor (rhIGF-1) can prevent the acute net catabolic effect of hypoxia, as reflected in a negative nitrogen balance, but that compared to normoxic conditions, weight gain is less pronounced. A combined therapeutic approach of both nutritional support and IGF was needed to induce a net anabolic effect.…”

mentioning

confidence: 99%

“…The study of IIOKA et al [12] shows that rh insulinlike growth factor (rhIGF-1) can prevent the acute net catabolic effect of hypoxia, as reflected in a negative nitrogen balance, but that compared to normoxic conditions, weight gain is less pronounced. A combined therapeutic approach of both nutritional support and IGF was needed to induce a net anabolic effect.…”

mentioning

confidence: 99%

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Hypoxia, nitrogen balance and body weight

Schols¹,

Westerterp²

2002

Eur Respir J

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Recent clinical studies have shown that acute exacerbations of chronic obstructive pulmonary disease (COPD) are characterised by disturbances in the balance between dietary intake and energy expenditure [1,2] as well as by a negative nitrogen balance [3]. Since weight loss prior to and during hospitalisation for an acute exacerbation has been related to poor outcome in terms of mortality and readmission rate [4,5], it is important to prevent or treat this complication. It is yet unclear to what extent factors contributing to weight loss, during acute disease exacerbations, are similar to stable disease. Elevated energy requirement of physical activity has been implicated during stable disease [6] but is unlikely to be an important factor during acute disease, when the activity level is probably very low. Hypoxia is otherwise implicated as a potential trigger of reduced dietary intake and metabolic alterations during acute exacerbations, while in stable disease, there is no strong relationship between resting arterial oxygen tension and nutritional status.Hypobaric hypoxia, as applied in high-altitude studies, clearly induces weight loss and is an interesting human model to investigate the influence of acute hypoxia. There is evidence that the altitude limit for the maintenance of body weight in humans isy5,000 m [7]. Acute transfer from sea level to altitude usually results in weight loss, but the rate of weight loss diminishes when the food supply is adequate. Reduced dietary intake is initially the result of a reduced meal size because of a rapid increase in satiety during the meal [8]. Part of the effect of reduced meal size on daily dietary intake can be compensated for by an increase in meal frequency. At altitudes of o7,000 m, acute mountain symptoms result in suppression of hunger and the desire to eat [8], possibly related to a reduction in appetite through leptin, a key mediator in the neuroendocrine regulation of food intake [9]. The effect of hypobaric hypoxia on resting metabolic rate is unclear. High-altitude studies are limited by the fact that subjects are often highly trained and have a physical activity related energy expenditure that is comparable to that of endurance athletes. A more specific study on nitrogen balance during a prolonged stay at 5,000 m showed no impairment of protein digestibility [10]. However, glycine metabolism, as measured with glycine ( 15 N), changed as a function of altitude exposure. Urinary excretion of 15 N from intravenous glycine administration, as a fraction of urinary nitrogen, increased from 20.6% after 4 days to 38.0% after 13 days at altitude (pv0.05). It was hypothesised that the increased 15 N excretion was due to increased oxidation of glycine as a function of altitude exposure. Others have also observed an altitude-induced increase in capillary leakage resulting in a renal loss of amino acids [11].Experimental models subjecting animals to a hypoxic environment, i.e. that of IIOKA et al. [12] in the current issue of this journal, are comparable to an altit...

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Hypoxia, nitrogen balance and body weight

Schols¹,

Westerterp²

2002

Eur Respir J

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“…Hypoxia can serve as a potential trigger of reduced dietary intake (8,15,30) and decreased circulating IGF-I and IGFBP-3 (5,16,21,22). Total body energy balance (V O 2 /daily food intake), hemoglobin and lactate levels, and arterial oxygenation were similar to those of the control group, within normal physiological range (12,27).…”

Section: The Experimental Modelmentioning

confidence: 71%

Chronic upper airway resistive loading induces growth retardation via the GH/IGF-I axis in prepubescent rats

Tarasiuk¹,

Segev²

2007

Journal of Applied Physiology

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Tarasiuk A, Segev Y. Chronic upper airway resistive loading induces growth retardation via the GH/IGF-I axis in prepubescent rats. J Appl Physiol 102: [913][914][915][916][917][918] 2007. First published November 30, 2006; doi:10.1152/japplphysiol.00838.2006.-The effect of upper airway loading on longitudinal bone growth and various components of the growth hormone (GH)/insulin-like growth factor I (IGF-I) axis has not been fully elucidated. In the present study, the effect of chronic resistive airway loading (CAL) in a prepubescent rat model on linear bone growth and weight gain was investigated. We hypothesize that CAL induced in prepubescent rats will lead to impaired longitudinal growth due to impairment in circulating and liver GH/IGF-I parameters. The tracheae of 22-day-old rats were obstructed by tracheal banding to increase inspiratory esophageal pressure. The GH/IGF-I markers were analyzed using ELISA, RT-PCR, and Western immunoblot analysis 14 days after surgery. Animals exhibited impaired longitudinal growth as demonstrated by reduction of tibia and tail length gains by 40% (P Ͻ 0.0001) and body weight gain by 24% (P Ͻ 0.0001). No differences were seen in total body energy balance, i.e., oxygen consumption, daily food intake, or arterial blood gases. Circulating GH, IGF-I, and IGF binding protein-3 (IGFBP-3) levels were reduced by 40% (P ϭ 0.037), 30% (P Ͻ 0.006), and 27% (P ϭ 0.02), respectively, in the CAL group. Liver IGF-I mRNA level decreased by 20% (P Ͻ 0.0002), whereas GH receptor mRNA and protein expression were unchanged. We conclude that impaired longitudinal growth in prepubescent CAL rats is related to a decrease in GH, IGF-I, and IGFBP-3 levels. chronic resistive loading; growth hormone; insulin-like growth factor I; insulin-like growth factor binding protein-3; prepuberty ONE OF THE CONSEQUENCES OF chronic resistive airway loading (CAL) in adult rats is malfunction in body weight gain (12, 27) without effect on longitudinal bone growth (35). The failure to gain weight was not related to decreased caloric intake (12) and was recently attributed to a decline in serum insulin-like growth factor I (IGF-I) levels (35). The endocrine effect of pituitary-secreted growth hormone (GH) is induction of IGF-I and IGF binding protein-3 (IGFBP-3) synthesis in various organs, including the liver; both are highly correlated with the 24-h mean GH levels (3, 7). This effect is mediated via activation of GH receptor (GHR), which is extensively distributed throughout many tissues (9). Impairment of the GH/IGF-I axis in prepubescent rats, before bone growth is completed, leads to skeletal growth retardation (31). The effect of CAL on the GH/IGF-I axis and longitudinal growth in prepuberty rats is not known.In the present study, the effect of CAL on longitudinal growth and weight gain was studied using the prepubescent rat model. We hypothesize that CAL will impair the GH/IGF-I axis, consequently leading to longitudinal growth retardation. We explored the effect of CAL on linear growth, serum GH, IGF-I, and ...

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“…Depressed IGF-I is independent from nutritional status [39]. In animal models, IGF-I administration only partially reverses the catabolic effects of hypoxaemia [40].…”

Section: Hypoxaemiamentioning

confidence: 99%

Endocrinological derangements in COPD

Laghi

Adıgüzel²,

Tobin³

2009

Eur Respir J

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Chronic obstructive pulmonary disease (COPD) is no longer considered to affect only the lungs and airways but also the rest of the body. The systemic manifestations of COPD include a number of endocrine disorders, such as those involving the pituitary, the thyroid, the gonads, the adrenals and the pancreas.The mechanisms by which COPD alters endocrine function are incompletely understood but likely involve hypoxaemia, hypercapnia, systemic inflammation and glucocorticoid administration. Altered endocrine function can worsen the clinical manifestations of COPD through several mechanisms, including decreased protein anabolism, increased protein catabolism, nonenzymatic glycosylation and activation of the rennin-angiotensin-aldosterone system.Systemic effects of endocrine disorders include abnormalities in control of breathing, decreases in respiratory and limb-muscle mass and function, worsening of respiratory mechanics, impairment of cardiac function and disorders of fluid balance.Research on endocrine manifestations of COPD embraces techniques of molecular biology, integrative physiology and controlled clinical trials. A sound understanding of the various disorders of endocrine function associated with COPD is prudent for every physician who practices pulmonary medicine.

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Effects of insulin-like growth factor on nitrogen balance during hypoxic exposure

Cited by 12 publications

References 34 publications

Hypoxia, nitrogen balance and body weight

Hypoxia, nitrogen balance and body weight

Chronic upper airway resistive loading induces growth retardation via the GH/IGF-I axis in prepubescent rats

Endocrinological derangements in COPD

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