scholarly journals Negative energy balance plays a major role in the IGF-I response to exercise training

2004 ◽  
Vol 96 (1) ◽  
pp. 276-282 ◽  
Author(s):  
Dan Nemet ◽  
Peter H. Connolly ◽  
Andria M. Pontello-Pescatello ◽  
Christie Rose-Gottron ◽  
Jennifer K. Larson ◽  
...  
Keyword(s):  
Energy Balance ◽  
Exercise Training ◽  
Energy Intake ◽  
Binding Protein ◽  
Negative Energy ◽  
Negative Energy Balance ◽  
Positive Energy ◽  
Igf I ◽  
Igf Binding ◽  
Igf Binding Protein

Circulating IGF-I is correlated with fitness, but results of prospective exercise training studies have been inconsistent, showing both increases and decreases in IGF-I. We hypothesized that energy balance, often not accounted for, is a regulating variable such that training plus an energy intake deficit would cause a reduction in IGF-I, whereas training plus energy intake excess would lead to an increased IGF-I. To test this, 19 young, healthy men completed a 7-day strenuous exercise program in which they were randomly assigned to either a positive energy balance [overfed (OF), n = 10] or negative energy balance [underfed (UF), n = 9] group. IGF-I (free and total), insulin, and IGF-binding protein-1 were measured before, during, and 1 wk after the training. Weight decreased in the UF subjects and increased in the OF subjects. Free and total IGF-I decreased substantially in the UF group ( P < 0.0005 for both), but, in the OF group, IGF-I remained unchanged. The UF group also demonstrated an increase in IGF-binding protein-1 ( P < 0.027), whereas glucose levels decreased ( P < 0.0005). In contrast, insulin was reduced in both the OF and UF exercise-training groups ( P < 0.044). Finally, within 7 days of the cessation of the diet and training regimen, IGF-I and IGF-binding protein-1 in the UF group returned to preintervention levels. We conclude that energy balance during periods of exercise training influences circulating IGF-I and related growth mediators. Exercise-associated mechanisms may inhibit increases in IGF-I early in the course of a training protocol, even in overfed subjects.

scholarly journals Negative energy balance in dairy cows is associated with specific changes in IGF-binding protein expression in the oviduct

Reproduction ◽  
2007 ◽  
Vol 135 (1) ◽  
pp. 63-75 ◽  
Author(s):  
M A Fenwick ◽  
S Llewellyn ◽  
R Fitzpatrick ◽  
D A Kenny ◽  
J J Murphy ◽  
...  
Keyword(s):  
Energy Balance ◽  
Protein Expression ◽  
Dairy Cows ◽  
Binding Protein ◽  
Negative Energy ◽  
Negative Energy Balance ◽  
Igf Binding ◽  
Igf Binding Protein

scholarly journals Effect of negative energy balance on the insulin-like growth factor system in pre-recruitment ovarian follicles of post partum dairy cows

Reproduction ◽  
2007 ◽  
Vol 133 (3) ◽  
pp. 627-639 ◽  
Author(s):  
S Llewellyn ◽  
R Fitzpatrick ◽  
D A Kenny ◽  
J J Murphy ◽  
R J Scaramuzzi ◽  
...  
Keyword(s):  
Energy Balance ◽  
Mrna Expression ◽  
Post Partum ◽  
Ovarian Follicles ◽  
Negative Energy ◽  
Negative Energy Balance ◽  
Igf Binding Proteins ◽  
Igf I ◽  
Igf Binding ◽  
Ovarian Cyclicity

Post partumnegative energy balance (NEB) in dairy cattle is associated with a delayed return to ovarian cyclicity and reduced fertility. This study compared the IGF system of pre-recruitment ovarian follicles between cows in mild (n= 6) or severe (n= 6) NEB during early lactation. Ovaries were collected in the second weekpost partum, when circulating concentrations of IGF-I and glucose were lower (P< 0.01) in severe NEB cows. mRNA expression for IGF-II, type 1 IGF receptor (IGF-1R) and IGF-binding proteins (IGFBP)-1 to IGFBP-6 was determined byin situhybridisation in individual follicles using radiolabelled oligonucleotide probes. Follicles were classified as very small (1–2.5 mm) or small (2.5–5 mm) and healthy or atretic. Relative mRNA concentrations were measured as optical density (OD) units using image analysis. Thecal IGF-II mRNA expression was highest in very small, healthy follicles (P< 0.05). Granulosa cell IGFBP-2 was the only component to change with EB status, with higher mRNA expression in mild compared with severe NEB cows (P< 0.05). IGFBP-1 and IGFBP-3 mRNA expression were undetectable. IGF-1R, IGFBP-4 and IGFBP-5 mRNA expression were not significantly altered by follicle size or health, but IGFBP-5 tended to increase in atretic follicles. The pattern of IGFBP-6 mRNA expression in theca paralleled that of IGF-II mRNA, with higher (P< 0.05) levels in healthy, very small follicles. In conclusion, the reduced expression of IGFBP-2 mRNA in severe NEB cows may alter the bioavailability of circulating IGF-I and locally produced IGF-II to modulate the pre-recruitment stages of follicles required to maintain normalpost partumovarian cyclicity.

Hypothalamic regulation of energy homeostasis when consuming diets of different energy concentrations: Comparison between Tibetan and Small-tailed Han sheep

2021 ◽  
pp. 1-25
Author(s):  
Xiaoping Jing ◽  
Yamin Guo ◽  
Allan Degen ◽  
Wenji Wang ◽  
Jingpeng Kang ◽  
...  
Keyword(s):  
Body Weight ◽  
Energy Balance ◽  
Energy Intake ◽  
Energy Homeostasis ◽  
Negative Energy ◽  
Negative Energy Balance ◽  
Positive Energy ◽  
Tibetan Sheep ◽  
Protein Expressions ◽  
Positive Energy Balance

Abstract Seasonal energy intake of Tibetan sheep on the harsh Qinghai-Tibetan Plateau (QTP) fluctuates greatly and is often well below maintenance requirements. The aim of this study was to gain insight into how the hypothalamus regulates energy homeostasis in Tibetan and Small-tailed Han sheep. We compared Tibetan and Small-tailed Han sheep (n=24 of each breed), which were offered one of four diets that differed in digestible energy (DE) densities: 8.21, 9.33, 10.45 and 11.57 MJ/kg dry matter. Sheep were weighed every two weeks, and it was assumed that the change in body weight reflected the change in energy balance. The arcuate nucleus of the hypothalamus in Tibetan sheep had greater protein expressions of neuropeptide Y (NPY) and agouti-related peptide (AgRP) when in negative energy balance, but lesser protein expressions of proopiomelanocortin (POMC) and cocaine and amphetamine-regulated transcript (CART) when in positive energy balance than Small-tailed Han sheep. As a result, Tibetan sheep had a lesser body weight (BW) loss when in negative energy balance and stored more energy and gained more BW when in positive energy balance than Small-tailed Han sheep with the same dietary intake. Moreover, in the hypothalamic AMPK regulation pathway, Tibetan sheep had greater AMPKα2 protein expression than Small-tailed Han sheep, which supported the premise of a better ability to regulate energy homeostasis and better growth performance. These differences in the hypothalamic NPY/AgRP, POMC/CART and AMPK pathways between breeds conferred an advantage to the Tibetan over Small-tailed Han sheep to cope with low energy intake on the harsh QTP.

Specimen processing time and measurement of total insulin-like growth factor-I (IGF-I), free IGF-I, and IGF binding protein-3 (IGFBP-3)

2006 ◽  
Vol 16 (2) ◽  
pp. 86-92 ◽  
Author(s):  
Tiffany G. Harris ◽  
Howard D. Strickler ◽  
Herbert Yu ◽  
Michael N. Pollak ◽  
E. Scott Monrad ◽  
...  
Keyword(s):  
Growth Factor ◽  
Processing Time ◽  
Binding Protein ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Igf I ◽  
Specimen Processing ◽  
Igf Binding ◽  
Igf Binding Protein ◽  
Igfbp 3

scholarly journals MK-677, an Orally Active Growth Hormone Secretagogue, Reverses Diet-Induced Catabolism1

1998 ◽  
Vol 83 (2) ◽  
pp. 320-325 ◽  
Author(s):  
M. G. Murphy ◽  
L. M. Plunkett ◽  
B. J. Gertz ◽  
W. He ◽  
J. Wittreich ◽  
...  
Keyword(s):  
Placebo Group ◽  
Caloric Restriction ◽  
Nitrogen Balance ◽  
Binding Protein ◽  
Growth Hormone Secretagogue ◽  
Significant Difference ◽  
Igf I ◽  
Igf Binding ◽  
Igf Binding Protein ◽  
Orally Active

The reversal of diet-induced negative nitrogen balance by GH suggests a possible therapeutic role for GH treatment in catabolic patients. A double-blind, randomized, placebo-controlled, two-period, cross-over study was designed to investigate whether MK-677, an orally active nonpeptide mimic of GH-releasing peptide, can reverse diet-induced protein catabolism. Eight healthy volunteers (ages 24–39 yr) were calorically restricted (18 kcal/kg·day) for two 14-day periods. During the last 7 days of each diet period, subjects received either oral MK-677 25 mg or placebo once daily. There was a 14- to 21-day washout interval between periods. During the first week of caloric restriction (i.e. diet alone), daily nitrogen losses were similar for both treatment groups (mean ± se; MK-677 group −2.67 ± 0.40 g/day vs. placebo group− 2.83 ± 0.26 g/day). During the second week (diet and study drug), mean daily nitrogen balance was 0.31 ± 0.21 g/day in the MK-677 treatment group compared with −1.48 ± 0.21 g/day in the placebo group (P &lt; 0.01). MK-677 improved nitrogen balance integrated over the 7 days of treatment; area under the curve day 8–14 nitrogen balance response was +2.69 ± 5.0 (se) for MK-677 and −8.97 ± 5.26 g·day for placebo (P &lt; 0.001). MK-677 produced a peak GH response of 55.9 ± 31.7 μg/L after single dose (day 1 of treatment) and 22.6 ± 9.3 μg/L after a week of dosing compared with placebo treatment peak GH values of approximately 9 (treatment day 1) and approximately 7 μg/L (treatment day 7). Following the initial 7-day caloric restriction, insulin-like growth factor-I (IGF-I) declined from 232 ± 25 to 186 ± 19 ng/mL in the MK-677 group and from 236 ± 19 to 174 ± 23 ng/mL in the placebo group. Mean IGF-I concentration increased significantly during MK-677 to 264 ± 31 ng/mL (mean for the last 5 days of treatment) compared with 188 ± 19 ng/mL with placebo (P &lt; 0.01). No significant difference in IGF binding protein-2 was found between the MK-677 and placebo treatments. However, the mean in IGF binding protein-3 for the last 5 days of MK-677 treatment was also significantly increased to 3273 ± 330 ng/mL (mean ± se) compared with placebo 2604 ± 253 ng/mL (P &lt; 0.01). Neither the serum cortisol nor the PRL response was significantly greater after 7 days of MK-677 dosing compared with 7 days of placebo. MK-677 (25 mg) was generally well tolerated and without clinically significant adverse experiences. In conclusion, MK-677 reverses diet-induced nitrogen wasting, suggesting that if these short-term anabolic effects are maintained in patients who are catabolic because of certain acute or chronic disease states, it may be useful in treating catabolic conditions.

scholarly journals Genetic Determinants of Circulating Insulin-Like Growth Factor (IGF)-I, IGF Binding Protein (BP)-1, and IGFBP-3 Levels in a Multiethnic Population

2007 ◽  
Vol 92 (9) ◽  
pp. 3660-3666 ◽  
Author(s):  
Iona Cheng ◽  
Katherine DeLellis Henderson ◽  
Christopher A. Haiman ◽  
Laurence N. Kolonel ◽  
Brian E. Henderson ◽  
...  
Keyword(s):  
Growth Factor ◽  
Binding Protein ◽  
Insulin Like Growth Factor ◽  
Genetic Determinants ◽  
Igf I ◽  
Igf Binding ◽  
Multiethnic Population ◽  
Igf Binding Protein ◽  
Igfbp 3

Energy Balance and Energy Availability During a Selection Course for Belgian Paratroopers

2021 ◽  
Author(s):  
Patrick Mullie ◽  
Pieter Maes ◽  
Laurens van Veelen ◽  
Damien Van Tiggelen ◽  
Peter Clarys
Keyword(s):  
Physical Activity ◽  
Energy Balance ◽  
Energy Expenditure ◽  
Metabolic Rate ◽  
Energy Intake ◽  
Rest Metabolic Rate ◽  
Negative Energy ◽  
Fat Free Mass ◽  
Negative Energy Balance ◽  
Energy Availability

ABSTRACT Introduction Adequate energy supply is a prerequisite for optimal performances and recovery. The aims of the present study were to estimate energy balance and energy availability during a selection course for Belgian paratroopers. Methods Energy expenditure by physical activity was measured with accelerometer (ActiGraph GT3X+, ActiGraph LLC, Pensacola, FL, USA) and rest metabolic rate in Cal.d−1 with Tinsley et al.’s equation based on fat-free mass = 25.9 × fat-free mass in kg + 284. Participants had only access to the French individual combat rations of 3,600 Cal.d−1, and body fat mass was measured with quadripolar impedance (Omron BF508, Omron, Osaka, Japan). Energy availability was calculated by the formula: ([energy intake in foods and beverages] − [energy expenditure physical activity])/kg FFM−1.d−1, with FFM = fat-free mass. Results Mean (SD) age of the 35 participants was 25.1 (4.18) years, and mean (SD) percentage fat mass was 12.0% (3.82). Mean (SD) total energy expenditure, i.e., the sum of rest metabolic rate, dietary-induced thermogenesis, and physical activity, was 5,262 Cal.d−1 (621.2), with percentile 25 at 4,791 Cal.d−1 and percentile 75 at 5,647 Cal.d−1, a difference of 856 Cal.d−1. Mean daily energy intake was 3,600 Cal.d−1, giving a negative energy balance of 1,662 (621.2) Cal.d−1. Mean energy availability was 9.3 Cal.kg FFM−1.d−1. Eleven of the 35 participants performed with a negative energy balance of 2,000 Cal.d−1, and only five participants out of 35 participants performed at a less than 1,000 Cal.d−1 negative energy balance level. Conclusions Energy intake is not optimal as indicated by the negative energy balance and the low energy availability, which means that the participants to this selection course had to perform in suboptimal conditions.

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