scholarly journals Mathematical Modeling of Glucose Homeostasis and Its Relationship With Energy Balance and Body Fat

Obesity ◽  
2009 ◽  
Vol 17 (4) ◽  
pp. 632-639 ◽  
Author(s):  
James M.D. Smith ◽  
James A. Maas ◽  
Philip C. Garnsworthy ◽  
Markus R. Owen ◽  
Stephen Coombes ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Energy Balance ◽  
Body Fat ◽  
Glucose Homeostasis

scholarly journals SUN-637 The Impact of Hyperandrogenemia and Western-Style Diet on Post-Pregnancy Metabolism in Nonhuman Primates

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Diana Lynn Takahashi ◽  
Emily Mishler ◽  
Ov Daniel Slayden ◽  
Jon D Hennebold ◽  
Charles T Roberts ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Body Fat ◽  
Glucose Homeostasis ◽  
Polycystic Ovary ◽  
Mean Value ◽  
Fat Percentage ◽  
Primate Model ◽  
Intravenous Glucose ◽  
Intravenous Glucose Tolerance Tests ◽  
The Impact

Abstract Polycystic ovary syndrome (PCOS) often is associated with hyperandrogenemia and an increased incidence of obesity and type 2 diabetes. To understand the separate and combined effects of androgens and obesity on reproductive and metabolic parameters, our group established a nonhuman primate model consisting of animals receiving either testosterone (T, mean value of 1.4 ng/mL), an obesogenic western-style diet (WSD, 36% of calories from fat compared to 16% in normal monkey chow), or a combination of T+WSD. T+WSD increased insulin resistance compared to WSD alone after three years of treatment and reduced fertility. Those T+WSD animals that became pregnant had a mild worsening of glucose homeostasis during pregnancy. The current study sought to determine how T+WSD affected post-pregnancy metabolic health and whether T+WSD led to the worsening of insulin resistance after pregnancy. Intravenous glucose tolerance tests (ivGTT) were performed 1) before pregnancy, 2) approximately 3-4 months after C-section, which occurred between gestational day 130-135 (3rd trimester), and 3) one year post C-section. All animal groups tended to show increases in weight, BMI, and body fat percentage after pregnancy. Both WSD groups (WSD and T+WSD) had higher overall weights, BMI, and body fat percentages. Measures of insulin sensitivity such as fasting insulin, glucose, and insulin area under the curves during an ivGTT and homeostatic model of insulin resistance (HOMA-IR) all increased over time, but there were no differences between groups. The lack of treatment effect on measures of insulin resistance may be due to the fact that animals that did not become pregnant had significantly higher indices of insulin resistance. Experimental animals underwent a second round of fertility trials thereby allowing for a comparison of glucose homeostasis for those animals that became pregnant in both the 1st and 2nd trial. The WSD group demonstrated increased fasting glucose and glucose AUC during an early third trimester ivGTT in the second pregnancy compared to the first. The control, T, and T+WSD groups did not show significant differences in glucose homeostasis between the first and second pregnancy. These findings indicate that WSD consumption may increase the risk of worsened glucose homeostasis after pregnancy and during subsequent pregnancies. Testosterone, either in isolation or in combination with WSD, did not appear to have a significant impact on post-pregnancy metabolism or worsen metabolic outcomes in a second pregnancy.

WITHDRAWN: The leptin driven melanocortin pathway in the regulation of body fat and glucose homeostasis is sexually dimorphic

Appetite ◽  
2006 ◽  
Author(s):  
A.D. Strader ◽  
D.J. Clegg ◽  
H. Shi ◽  
J.B. Chambers ◽  
J.E. Sorrell ◽  
...  
Keyword(s):  
Body Fat ◽  
Glucose Homeostasis ◽  
Sexually Dimorphic

Loss of body fat during an arctic winter expedition

1977 ◽  
Vol 55 (6) ◽  
pp. 1235-1241 ◽  
Author(s):  
W. J. O'Hara ◽  
C. Allen ◽  
R. J. Shephard
Keyword(s):  
Weight Loss ◽  
Energy Balance ◽  
Body Fat ◽  
Lean Mass ◽  
Muscle Force ◽  
Aerobic Power ◽  
Canadian Arctic ◽  
Lean Tissue ◽  
Energy Expenditures ◽  
Daily Energy

Fifty-five soldiers have been observed over a vigorous 10-day sledging patrol in the Canadian arctic and subarctic. Initial observations showed a low level of physical fitness (26% body fat, aerobic power 41.9 ± 7.8 ml kg−1 min−1, handgrip force 43.7 ± 7.2 kg). Over the 2-week northern sojourn, energy expenditures as measured by a Kofranyi–Michaelis respirometer and diary observation averaged 3248 kcal (13.6 MJ) day−1, with a small (152 kcal (633 kJ)) positive daily energy balance. A weight loss of 1 kg, presumably water, was made good within 1 week of return to the south. A fat loss of some 3.9 kg was probably attributable largely to the demands of lean tissue synthesis. The lean mass was increased by 3.9 kg over the trial, with parallel gains of muscle force and aerobic power. The rapid mobilization of depot fat led to marked ketonuria.

Sexually different actions of leptin in proopiomelanocortin neurons to regulate glucose homeostasis

2008 ◽  
Vol 294 (3) ◽  
pp. E630-E639 ◽  
Author(s):  
Haifei Shi ◽  
April D. Strader ◽  
Joyce E. Sorrell ◽  
James B. Chambers ◽  
Stephen C. Woods ◽  
...  
Keyword(s):  
Energy Balance ◽  
Glucose Homeostasis ◽  
High Fat Diet ◽  
Arcuate Nucleus ◽  
Fat Distribution ◽  
Male And Female ◽  
Female Mice ◽  
Leptin Receptors ◽  
Exogenous Glucose ◽  
Anorectic Effect

Leptin regulates energy balance and glucose homeostasis, at least in part, via activation of receptors in the arcuate nucleus of the hypothalamus located in proopiomelanocortin (POMC) neurons. Females have greater sensitivity to central leptin than males, suggested by a greater anorectic effect of central leptin administration in females. We hypothesized that the regulation of energy balance and peripheral glucose homeostasis of female rodents would be affected to a greater extent than in males if the action of leptin in POMC neurons were disturbed. Male and female mice lacking leptin receptors only in POMC neurons gained significantly more body weight and accumulated more body fat. However, female mice gained disproportionately more visceral adiposity than males, and this appeared to be largely the result of differences in energy expenditure. When maintained on a high-fat diet (HFD), both male and female mutants had higher levels of insulin following exogenous glucose challenges. Chow- and HFD-fed males but not females had abnormal glucose disappearance curves following insulin administrations. Collectively, these data indicate that the action of leptin in POMC neurons is sexually different to influence the regulation of energy balance, fat distribution, and glucose homeostasis.

Body fat loss and compensatory mechanisms in response to different doses of aerobic exercise—a randomized controlled trial in overweight sedentary males

2012 ◽  
Vol 303 (6) ◽  
pp. R571-R579 ◽  
Author(s):  
Mads Rosenkilde ◽  
Pernille Auerbach ◽  
Michala Holm Reichkendler ◽  
Thorkil Ploug ◽  
Bente Merete Stallknecht ◽  
...  
Keyword(s):  
Randomized Controlled Trial ◽  
Body Composition ◽  
Energy Balance ◽  
Aerobic Exercise ◽  
Body Fat ◽  
Controlled Trial ◽  
Negative Energy ◽  
Compensatory Mechanisms ◽  
Randomized Controlled ◽  
Exercise Induced

The amount of weight loss induced by exercise is often disappointing. A diet-induced negative energy balance triggers compensatory mechanisms, e.g., lower metabolic rate and increased appetite. However, knowledge about potential compensatory mechanisms triggered by increased aerobic exercise is limited. A randomized controlled trial was performed in healthy, sedentary, moderately overweight young men to examine the effects of increasing doses of aerobic exercise on body composition, accumulated energy balance, and the degree of compensation. Eighteen participants were randomized to a continuous sedentary control group, 21 to a moderate-exercise (MOD; 300 kcal/day), and 22 to a high-exercise (HIGH; 600 kcal/day) group for 13 wk, corresponding to ∼30 and 60 min of daily aerobic exercise, respectively. Body weight (MOD: −3.6 kg, P < 0.001; HIGH: −2.7 kg, P = 0.01) and fat mass (MOD: −4.0 kg, P < 0.001 and HIGH: −3.8 kg, P < 0.001) decreased similarly in both exercise groups. Although the exercise-induced energy expenditure in HIGH was twice that of MOD, the resulting accumulated energy balance, calculated from changes in body composition, was not different (MOD: −39.6 Mcal, HIGH: −34.3 Mcal, not significant). Energy balance was 83% more negative than expected in MOD, while it was 20% less negative than expected in HIGH. No statistically significant changes were found in energy intake or nonexercise physical activity that could explain the different compensatory responses associated with 30 vs. 60 min of daily aerobic exercise. In conclusion, a similar body fat loss was obtained regardless of exercise dose. A moderate dose of exercise induced a markedly greater than expected negative energy balance, while a higher dose induced a small but quantifiable degree of compensation.

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