Body fat influences sexual maturation in captive male Belding's ground squirrels

1988 ◽  
Vol 66 (7) ◽  
pp. 1620-1625 ◽  
Author(s):  
Warren G. Holmes
Keyword(s):  
Body Fat ◽  
Sexual Maturation ◽  
Serum Testosterone ◽  
Ground Squirrels ◽  
Constant Darkness ◽  
Physiological Indicators ◽  
Abundant Food ◽  
Cold Room ◽  
Fat Stores ◽  
Spermophilus Beldingi

The influence of white adipose tissue on sexual maturation was investigated in captive-born male Belding's ground squirrels (Spermophilus beldingi). Juveniles were given abundant food during the summer and by fall achieved prehibernation body masses approximating those of sexually mature males. Immediately before being placed in a cold room (5–8 °C, constant darkness) for a 7-month hibernation period, fat was surgically removed (lipectomy) or left intact (sham lipectomy). The following spring, paired testes mass, serum testosterone, and spermatogenesis were monitored, mating tests were conducted, and body fat levels were determined. All three physiological indicators of reproductive status were significantly higher in sham-lipectomized than in lipectomized males, only sham-lipectomized males inseminated females, and body fat levels were significantly higher in sham-lipectomized than in lipectomized males. Thus, sexual maturation was accelerated in male Belding's ground squirrels by providing juveniles abundant food so they achieved body masses typical of adults; body fat was essential for accelerated development. In nature, males may forego reproductive development until they can acquire adequate fat stores to survive hibernation and activate their reproductive system and until they gain social experience important in male–male competition for mates.

Seasonal effects of food provisioning on body fat, insulin, and corticosterone in free-living juvenile Belding's ground squirrels (Spermophilus beldingi)

2002 ◽  
Vol 80 (2) ◽  
pp. 366-371 ◽  
Author(s):  
Scott Nunes ◽  
Eva-Maria Muecke ◽  
Kay E Holekamp
Keyword(s):  
Body Fat ◽  
Plasma Insulin ◽  
Plasma Concentrations ◽  
Plasma Corticosterone ◽  
Ground Squirrels ◽  
Seasonal Effects ◽  
Free Living ◽  
Active Season ◽  
Extra Food ◽  
Spermophilus Beldingi

We evaluated the relationship between body fat and the metabolic hormones insulin and corticosterone in free-living juvenile Belding's ground squirrels (Spermophilus beldingi). Some free-living juveniles were provisioned with extra food high in fat and calories, and unprovisioned juveniles were used as controls. Body fat (as a percentage of body mass) of squirrels was regularly evaluated using non-invasive methods. Blood samples were also regularly collected from juveniles and assayed for plasma concentrations of insulin and corticosterone. Provisioned juveniles were fatter than unprovisioned juveniles during most of the active season, but differences in body fat disappeared near the end of summer as juveniles began fattening for hibernation. Thus, our data indicate that although body fat may fluctuate with energy availability early in the active season, it is regulated at precise levels as squirrels prepare for winter. Plasma corticosterone concentrations did not differ between provisioned and unprovisioned juveniles. However, plasma insulin concentrations were greater in provisioned than in unprovisioned juveniles early in the summer. Differences in insulin concentrations disappeared later in the active season, just prior to the disappearance of differences in body fat. Moreover, plasma insulin concentrations were significantly correlated with subsequent changes in body fat. Thus, our data suggest a link between insulin and seasonal regulation of body fat in juvenile S. beldingi.

Nutritional Practices of Elite Female Surfers during Training and Competition

1998 ◽  
Vol 8 (1) ◽  
pp. 36-48 ◽  
Author(s):  
Jenni M. Felder ◽  
Louise M. Burke ◽  
Brian J. Lowdon ◽  
David Cameron-Smith ◽  
Gregory R. Collier
Keyword(s):  
Body Weight ◽  
Energy Intake ◽  
Body Fat ◽  
Protein Intake ◽  
Nutrient Intakes ◽  
Dietary Practices ◽  
Zinc Intake ◽  
Fat Stores ◽  
Food Diaries ◽  
And Training

The aim of this study was to assess the dietary practices of 10 elite female surfers. Four- and five-day food diaries completed over competition and training periods demonstrated energy intakes (mean ± SD) of 9,468 kJ (±2,007) and 8,397 kJ (±1,831), respectively. This level of energy intake was less than that estimated for the requirements of surfing. Female surfers' carbohydrate intakes failed to meet the recommendations, and suboptimal zinc intake was observed with 90% of subjects not meeting the Australian RDI. Comparisons between competition and training demonstrated that carbohydrate (g and g/kg body weight) and confectionary (g) intakes were significantly higher (p < .05) and protein intake was significantly lower (p < .05) during competition. These results show that although body fat stores were not compromised (mean 22%), self-reported energy, carbohydrate, and nutrient intakes were marginal in elite female surfers. Questionnaires revealed that 90% of surfers did not have good nutritional habits while traveling, which was compounded by a lack of knowledge of nutritional practices.

scholarly journals Leptin Responsiveness in Chronically Decerebrate Rats

Endocrinology ◽  
2007 ◽  
Vol 148 (10) ◽  
pp. 4623-4633 ◽  
Author(s):  
Ruth B. S. Harris ◽  
Timothy J. Bartness ◽  
Harvey J. Grill
Keyword(s):  
Energy Expenditure ◽  
Body Fat ◽  
Serum Testosterone ◽  
Control Group ◽  
Energy Status ◽  
Lower Serum ◽  
Peripheral Tissues ◽  
Leptin Receptors ◽  
Ad Libitum ◽  
Ad Libitum Intake

Peripheral infusions of physiological doses of leptin decrease body fat mass, but it is not known whether this results from direct effects on peripheral tissue or activation of central leptin receptors. In this study, we infused chronically decerebrate (CD) rats, in which the forebrain was surgically isolated from the caudal brainstem, with 60 μg leptin/d or PBS for 14 d from ip mini-osmotic pumps. The CD rats were tube fed an amount of food equivalent to the intake of ad libitum-fed intact controls or 75% of this amount to account for their reduced energy expenditure. Control rats fed ad libitum or tube fed 75, 100, or 125% of their ad libitum intake also were peripherally infused with leptin or PBS. CD rats had a lower serum testosterone, energy expenditure, and lean body mass compared with controls but had increased levels of adiponectin and leptin and were obese. Leptin increased body fat and decreased energy expenditure during the light period in 100%-fed CD rats, but not 75%-fed CD rats. Leptin decreased body fat of ad libitum- and 100%-fed but not 75%-fed or 125%-fed intact controls. Energy expenditure did not change in any control group. These results show that leptin can change body fat independent of a change in food intake or energy expenditure, that the forebrain normally prevents leptin from inhibiting energy expenditure through mechanisms initiated in the caudal brainstem or peripheral tissues, and that the leptin response in both intact and CD rats is determined by the energy status of the animal.

scholarly journals Characterization of the imaginal reproductive diapause of Oebalus poecilus (Dallas) (Hemiptera: Pentatomidae)

2003 ◽  
Vol 63 (4) ◽  
pp. 695-703 ◽  
Author(s):  
R. S. S. Santos ◽  
L. R. Redaelli ◽  
L. M. G. Diefenbach ◽  
H. P. Romanowski ◽  
H. F. Prando
Keyword(s):  
Body Fat ◽  
Sexual Maturation ◽  
Abdominal Cavity ◽  
Reproductive Organs ◽  
Reproductive Organ ◽  
The Body ◽  
Reproductive Diapause ◽  
Male And Female ◽  
In The Beginning

The state of development of the internal reproductive organs of male and female Oebalus poecilus (Dallas) as well as the body fat amount in the abdominal cavity during hibernation, of individuals sampled in bamboo litter in Eldorado do Sul (30º02'S and 51°23'W), RS, Brazil was investigated. Females and males showed the abdominal cavity filled with body fat in the beginning of the hibernation phase. The decrease in fat reserve level occurred from August on for males and from October on for females. Ovaries and testis doubled in length and tripled in width from immature to the reproductive phase. Male sexual maturation occurred in the hibernation sites while for females it occurred later on outside of the sites. Reproductive organ immaturity and abdominal body fat hypertrophy characterized the diapause of O. poecilus.

scholarly journals Influence of voluntary exercise on hypothalamic norepinephrine

1998 ◽  
Vol 85 (3) ◽  
pp. 962-966 ◽  
Author(s):  
Gavin W. Lambert ◽  
Ingibjorg H. Jonsdottir
Keyword(s):  
Exercise Training ◽  
Body Fat ◽  
Fat Mass ◽  
Strong Relationship ◽  
Abdominal Fat ◽  
Voluntary Exercise ◽  
Plasma Norepinephrine ◽  
Nervous Function ◽  
Fat Stores ◽  
Sympathetic Nervous

We combined hypothalamic tissue and plasma determinations of norepinephrine, dihydroxyphenylalanine, and dihydroxyphenylglycol with measurements of abdominal fat in voluntary running rats to examine the relationship among exercise training, hypothalamic and sympathetic nervous function, and body fat stores. The hypothalamic concentrations of norepinephrine, dihydroxyphenylalanine, and dihydroxyphenylglycol were reduced after exercise training ( P < 0.01), with the amount of norepinephrine being strongly associated with the plasma norepinephrine ( r = 0.58, P < 0.05) and dihydroxyphenylglycol ( r = 0.65, P = 0.01) concentrations. Exercise training resulted in a diminution in abdominal fat mass ( P < 0.01). A strong relationship existed between fat mass and hypothalamic norepinephrine content ( r = 0.83, P < 0.001). The presence of a positive relationship between the arterial and hypothalamic norepinephrine levels provides presumptive evidence of an association between noradrenergic neuronal activity of the hypothalamus and sympathetic nervous function. The observation that abdominal fat mass is linked with norepinephrine in the hypothalamus raises the possibility that alterations in body fat stores provide an afferent signal linking hypothalamic function and the activity of the sympathetic nervous system.

ON BODY FAT AND BODY WATER IN RATS

1955 ◽  
Vol 33 (1) ◽  
pp. 970-979 ◽  
Author(s):  
Louis-Marie Babineau ◽  
Edouard Pagé
Keyword(s):  
Adipose Tissue ◽  
Body Fat ◽  
Dry Matter ◽  
The Body ◽  
Energy Reserves ◽  
Experimental Conditions ◽  
Fat Depots ◽  
Excess Water ◽  
Fat Stores ◽  
Free Body

Under our experimental conditions, water represented 72% of the fat-free body mass. This constant was found to be completely independent of the magnitude of the fat depots. Consideration of the composition of various samples of adipose tissue suggests that the water to fat-free dry matter ratio is the same as in the body as a whole or that any "excess" water contributed by adipose tissue is so small in absolute amounts as to leave the global ratio essentially undisturbed. Rats exposed to cold had to draw on their fat stores during the first month of exposure but later replenished their energy reserves. The water to fat-free dry matter ratio was not affected.

scholarly journals Obesidade em adolescentes do Sul do Brasil: associação com fatores sociodemográficos, estilo de vida e estágio maturacional

2016 ◽  
Vol 18 (5) ◽  
pp. 557 ◽  
Author(s):  
Carlos Alencar Souza Alves Junior ◽  
Eliane Cristina de Andrade Gonçalves ◽  
Diego Augusto Santos Silva
Keyword(s):  
Physical Activity ◽  
High School Students ◽  
Body Fat ◽  
Sexual Maturation ◽  
Parental Education ◽  
Dietary Habits ◽  
Public Health Problem ◽  
Global Public Health ◽  
School Students ◽  
Pubertal Stage

DOI: http://dx.doi.org/10.5007/1980-0037.2016v18n5p557 Excess body fat is associated with chronic degenerative diseases, being a global public health problem. The aim of this study was to investigate the association of obesity with sociodemographic factors, lifestyle (physical activity, dietary habits) and sexual maturation in high school students of a city in southern Brazil. This is a crosssectional study with 820 adolescents enrolled in public high schools of São José, Santa Catarina, Brazil, aged 14-17 years. Obesity was estimated by body fat percentage (BF%). BF% was calculated using the Lohman equation, which considers the sum of skinfolds (triceps and subscapularis). Cutoff points proposed by William et al. were used to classify individuals into normal weight or obese. Independent variables were sex, age, economic status, parental education, eating habits, physical activity and sexual maturation. The prevalence of obesity was 17.2%. Females (OR: 4.22; 95% CI: 2.72-6.54) and young people at post-pubertal stage of sexual maturation (OR: 1.95; 95% CI: 1.33-2.86) were more likely to have obesity. These results may help health authorities in the planning of public policies to prevent obesity.

Ketone body metabolism in a ground squirrel during hibernation and fasting

1985 ◽  
Vol 249 (4) ◽  
pp. R462-R470 ◽  
Author(s):  
B. L. Krilowicz
Keyword(s):  
Energy Source ◽  
Glucose Uptake ◽  
Ground Squirrel ◽  
Ketone Body ◽  
Glucose Utilization ◽  
Ground Squirrels ◽  
Body Protein ◽  
Muscle Tissues ◽  
Spermophilus Beldingi

Hibernating Belding's ground squirrels (Spermophilus beldingi) are ketotic relative to fed nonhibernators. Muscles from torpid individuals, when incubated in media containing physiological concentrations of glucose and ketone, show reduced uptake of glucose in the presence of ketone. The magnitude of the reduction is dependent on ketone concentration and reaches 60% in heart and 100% in pectoralis at 1.4 mM ketone. Fasted squirrels are also ketotic. However, ketone does not reduce glucose uptake in muscles from fed or fasted animals. Glucose utilization by muscles decreases during a long-term fast, but the reduction is independent of ketone. Thus both a long-term fast and hibernation lead to changes in muscle tissues that decrease their reliance on glucose as an energy source. Ketosis leads to glucose sparing during hibernation, whereas muscle glucose utilization is decreased independently of ketone during a fast. The glucose sparing achieved in both hibernation and fasting leads to conservation of body protein, the major source of gluconeogenic precursors in fasting mammals.

Sign in / Sign up

Export Citation Format

Share Document