Daily exercise reduces fat, protein and body mass in male but not female rats.
*Body Mass Index; Adipose Tissue/*metabolism; Animals; Body Composition/*physiology; Body Weight/physiology; Energy Metabolism/*physiology; Female; Gonadal Steroid Hormones/physiology; Male; Physical Exertion/*physiology; Proteins/*metabolism; Rats; Sex Characteristics; Sprague-Dawley
This study was designed to compare the estimated energy balance, linear growth (body and bone lengths) and body composition (all components including body mass, total body water, fat, protein and ash) response to daily spontaneous running (DSR) in young male and female rats. We tested the hypothesis that due to gender differences in energy efficiency, DSR would reduce linear growth and body composition more in male rats. Fourteen male and sixteen female weanling Sprague-Dawley rats were randomly assigned to either a sedentary (SED) control (male 7, female 8) or DSR (male 7, female 8) group. The DSR rats were allowed to run spontaneously in running wheels while SED rats remained in standard rat cages for 9 weeks. Body mass, running distance and food intake were measured over the nine week period. Subsequently, chemical analysis was performed to measure carcass content of water, protein, fat and ash. Linear growth was assessed by measures of body and bone lengths. The estimated energy balance of the DSR rats was computed and compared between genders. Estimated energy balance was significantly more negative in females than males due to significantly greater DSR distance. Body and bone lengths were similar among the SED and DSR female and SED and DSR male rats. However, whole body mass, fat mass and protein mass were significantly lower only in DSR males. These results demonstrate that DSR reduced body mass, body fat and protein mass in male rats but not in female rats despite a more negative estimated energy balance in female rats. These findings suggest that females are better protected from an energy deficit due to DSR. Possible mechanisms include gender-specific hormonal responses.
Cortright R N; Chandler M P; Lemon P W; DiCarlo S E
Physiology & behavior
1997
1997-07
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/s0031-9384(97)00148-0" target="_blank" rel="noreferrer noopener">10.1016/s0031-9384(97)00148-0</a>
Diabetes reduces growth and body composition more in male than in female rats.
Aging/physiology; Animals; Blood Glucose/metabolism; Body Composition/*physiology; Body Weight/physiology; Diabetes Mellitus; Experimental/*physiopathology; Female; Growth/*physiology; Inbred Lew; Male; Rats; Sex Characteristics
Food restriction and/or starvation has a consistently greater and more permanent effect on physical growth in males than in females. Because diabetes may be viewed as being analogous to starvation, we tested the hypothesis that diabetes would reduce growth more in male than in female rats. Diabetes was induced with streptozotocin (65-125 mg/kg IP) at 3 weeks of age in 7 female and 10 male Lewis rats. Body weight (BW) and blood glucose (bGlc) were measured over the following 8 weeks. Subsequently, animals were assessed for body (ano-nasal; ANL) and bone length (tibia; TBL) and chemically analyzed for body composition. Results were compared to age-matched controls (male = 11; female = 9). A 2-way factorial analysis of covariance (ANCOVA), with body weight as the covariate, was used to test for statistical significance for the effects of gender and diabetes on body composition (fat and protein mass) and linear growth because control males and females had significantly different body weights. There were no significant differences in bGlc between genders. However, males had a greater decrease from controls in BW (-45% vs. -13%), protein (-48% vs. -11%), fat (-89% vs. -65%), TBL (-13% vs. 0%), and ANL (-17% vs. -5%) compared to females. In addition, males had a greater absolute decrease from controls in protein (-40 g vs. -5 g) and fat (-39 g vs. -23 g) mass. These results suggest that male rats are more susceptible than females to the deleterious effects of diabetes on linear growth and body composition.
Cortright R N; Collins H L; Chandler M P; Lemon P W; DiCarlo S E
Physiology & behavior
1996
1996-11
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/s0031-9384(96)00222-3" target="_blank" rel="noreferrer noopener">10.1016/s0031-9384(96)00222-3</a>