Prolonged Exercise Increases Serum Insulin-Like Growth Factor-Binding Protein Concentrations*

Suikkari, Anne‐Maria; Sane, Timo; Seppälä, Markku; Yki‐Järvinen, Hannele; Karonen, Sirkka-Liisa; Koivisto, Veikko A.

doi:10.1210/jcem-68-1-141

Cited by 96 publications

(48 citation statements)

References 21 publications

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“…Given the limited duration of exercise chosen for this study, it was thought unlikely that IGFBP-1 concentration would change (no effect was seen following 30 min of moderate exercise in a previous study (25)). IGFBP-1 concentration has, however, been shown to increase in response to exercise of longer duration or intensity (26,27). The production of IGFBP-1 by the liver is thought to be activated when circulating concentrations of metabolic substrates are low (28) and is also known to fluctuate dramatically according to insulin concentration (29,30).…”

Section: Discussionmentioning

confidence: 99%

Exercise-induced GH secretion is enhanced by the oral ingestion of melatonin in healthy adult male subjects

et al. 1999

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There is evidence that melatonin may play a role in modulating pituitary secretion, although the mechanisms are unclear. We examined the effects of a single dose of oral melatonin (5 mg) on exerciseinduced GH secretion. In a randomised, double-blind, placebo-controlled study, seven healthy male subjects undertook an initial period of graded bicycle ergometric exercise to determine maximum workload and oxygen uptake (VO 2 max ). Subjects were subsequently studied on two further occasions, receiving either melatonin or placebo in random order at the onset of each study (¹60 min). At 0 min a period of bicycle exercise was performed for 8 min at a workload corresponding to 70 % of that achieved at VO 2 max . Serum GH and IGF-binding protein-1 (IGFBP-1) concentration was measured at 15-min intervals from the onset of the study until 120 min post-exercise. Blood was also sampled for the measurement of plasma glucose, insulin, non-esterified fatty acids, IGFBP-3, melatonin and vasopressin concentration. There was an exercise-induced increase in GH concentration following melatonin which was greater compared with placebo as assessed by both area under the curve (P < 0.01) and peak increase in GH levels (P < 0.01). The peak increase in IGFBP-1 levels post-exercise was also significantly greater following melatonin compared with placebo (P < 0.01) but did not quite reach levels of significance as measured by area under the curve (P = 0.07). Since exercise-induced GH secretion is thought to be mediated predominantly through a hypothalamic pathway, it seems likely that melatonin facilitates GH secretion at a hypothalamic level.

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Section: Discussionmentioning

confidence: 99%

Exercise-induced GH secretion is enhanced by the oral ingestion of melatonin in healthy adult male subjects

et al. 1999

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“…From a clinical point of view, this makes IGFBP-1 at admission an interesting prognostic predictor, which also remained after multiple adjustment. IGFBP-1 has been described as the most likely acute regulator of IGF-I actions (25), and the hepatic production of IGFBP-1 is upregulated in response to proinflammatory cytokines (26) and physiological stresses (27) and is downregulated by insulin (13). There are several potential links between high levels of IGFBP-1 and increased cardiovascular risk.…”

Section: Baseline Characteristicsmentioning

confidence: 99%

IGF Binding Protein 1 Predicts Cardiovascular Morbidity and Mortality in Patients With Acute Myocardial Infarction and Type 2 Diabetes

et al. 2007

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OBJECTIVE -There are indications that the IGF system is related to both type 2 diabetes and cardiovascular disease (CVD). We tested the hypothesis that low IGF-I and high IGFbinding protein (IGFBP)-1 predict future cardiovascular mortality and morbidity in patients with acute myocardial infarction (AMI) and type 2 diabetes. RESEARCH DESIGN AND METHODS -The Diabetes MellitusInsulin-Glucose Infusion in Acute Myocardial Infarction (DIGAMI) 2 Trial recruited 1,253 patients with type 2 diabetes and AMI, of whom 575 were enrolled in a biochemical program with repeated blood sampling. Primary and secondary end points included adjudicated cardiovascular mortality and a composite of cardiovascular events (cardiovascular death, reinfarction, or stroke). Multiple Cox proportional hazard regression was used to study the relationship between the end points and the variables. Admission variables were used for the survival analysis and for blood glucose, and A1C updated mean values during follow-up were also available. CONCLUSIONS -High levels of IGFBP-1 at admission are associated with increased risk for cardiovascular mortality and morbidity in type 2 diabetes patients with AMI. RESULTS Diabetes Care 30:2343-2348, 2007P atients with type 2 diabetes have an increased risk for cardiovascular disease (CVD) (1). The prognosis after an acute myocardial infarction (AMI) does, indeed, already deteriorate at glucose levels in the upper normal range (2,3). The importance is underlined by the high prevalence of AMI patients with previously undetected glucose abnormalities (4 -6). The increased cardiovascular risk cannot be completely explained by traditional risk factors, and mechanisms amplifying their impact are not fully understood (7). Thus, the search for novel risk factors linking type 2 diabetes and CVD is important (8).The IGF-I system has been related to poor glucose control, and low levels of IGF-I have been related to future type 2 diabetes (9). In addition, the IGF-I system and especially low IGF-I, low IGF binding protein (IGFBP)-1, and high IGFBP-3 relate to increased cardiovascular risk (10,11). Thus, it is of interest to explore the IGF-I system as a potential novel risk factor and as a possible link between type 2 diabetes and subsequent cardiovascular complications (12). The hepatic production of IGFBP-1 is downregulated by insulin (13). Accordingly, in the general population, there is a correlation between low levels of IGFBP-1 and hyperinsulinemia, and these findings may link to an increased cardiovascular risk (14,15). However, IGFBP-1 concentrations rise during the development of type 2 diabetes, despite persisting hyperinsulinemia, indicating increased hepatic insulin resistance during disease progression (16,17). These observations were supported by van den Berghe et al. (18), who demonstrated that patients admitted to the intensive care unit with elevated levels of IGFBP-1 presented a poor prognosis regarding mortality, a finding that related to acute hepatic insulin resistance. Furthermore, there is a correla...

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“…However, exercise has been reported to increase both IGFBP-3 concentrations and IGFBP-3 proteolytic activity (Suikkari et al 1989b), possibly resulting in enhanced uptake of IGF-I into tissues. It has been suggested that the IGFBPs, particularly IGFBP-3, may function as a reservoir for the IGFs.…”

Section: Storage and Transport Of Igfsmentioning

confidence: 99%

Insulin-like growth factor-binding proteins: functional diversity or redundancy?

Murphy

1998

Journal of Molecular Endocrinology

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Prolonged Exercise Increases Serum Insulin-Like Growth Factor-Binding Protein Concentrations*

Cited by 96 publications

References 21 publications

Exercise-induced GH secretion is enhanced by the oral ingestion of melatonin in healthy adult male subjects

Exercise-induced GH secretion is enhanced by the oral ingestion of melatonin in healthy adult male subjects

IGF Binding Protein 1 Predicts Cardiovascular Morbidity and Mortality in Patients With Acute Myocardial Infarction and Type 2 Diabetes

Insulin-like growth factor-binding proteins: functional diversity or redundancy?

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