Influence of long-term exposure to adverse environments on organ weights and histology

A comparison was made of the morphological effects of cold, heat and simulated altitude on adult male rats given exposures of 24 weeks' duration. By the use of covariance analysis it was possible to determine the extent to which organ weights were dependent upon body weight and to adjust the values in order to remove body weight influences. For liver, heart and kidney, adjusted weights indicated temperature-dependency, while pressure-dependency was established for liver and kidney only. Histologically, temperature-dependency was indicated for liver, kidney, thyroid, adrenal and pituitary. Fur weight was reduced in heat but not altered in cold. Fasting in cold induced changes in adrenal and thymus weight and unusually high body weight loss; in heat, fasting caused a significant thymus weight loss without adrenal weight increase. The thymus-adrenal ratio was elevated during a 24-hour fast in all environments except cold, where it was decreased.

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Social stress and recovery: implications for body weight and body composition

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00371.2007 ◽

2007 ◽

Vol 293 (5) ◽

pp. R1864-R1874 ◽

Cited By ~ 74

Author(s):

Kellie L. K. Tamashiro ◽

Mary M. N. Nguyen ◽

Michelle M. Ostrander ◽

Stacy R. Gardner ◽

Li Yun Ma ◽

...

Keyword(s):

Weight Loss ◽

Body Composition ◽

Body Weight ◽

Adipose Tissue ◽

Social Status ◽

Social Stress ◽

Energy Homeostasis ◽

Body Weight Loss ◽

Male Rats ◽

Induced Changes

Social stress resulting from dominant-subordinate relationships is associated with body weight loss and altered body composition in subordinate (SUB) male rats. Here, we extend these findings to determine whether stress-induced changes in energy homeostasis persist when the social stress is removed, and the animal is allowed to recover. We examined body weight (BW), body composition, and relevant endocrine measures after one or two cycles of 14 days of social stress, each followed by 21 days of recovery in each rat's individual home cage. SUB lost significantly more BW during social housing in a visible burrow system (VBS) compared with dominant (DOM) animals. Weight loss during social stress was attributable to a decrease in adipose tissue in DOM and SUB, with an additional loss of lean tissue in SUB. During both 21-day recovery periods, DOM and SUB regained lost BW, but only SUB were hyperphagic. Following recovery, SUB had a relatively larger increase in adipose tissue and plasma leptin compared with DOM, indicating that body composition changes were dependent on social status. Control animals that were weight matched to SUB or male rats exposed to the VBS environment without females, and that did not form a social hierarchy, did not exhibit changes in body composition like SUB in the VBS. Therefore, chronic social stress causes social status-dependent changes in BW, composition and endocrine measures that persist after repeated stress and recovery cycles and that may ultimately lead to metabolic disorders and obesity.

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Diet and body weight loss in the rat during calorie restriction

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y68-017 ◽

1968 ◽

Vol 46 (1) ◽

pp. 101-107

Author(s):

Peter B. Karch ◽

John R. Beaton

Keyword(s):

Weight Loss ◽

Body Weight ◽

Body Fat ◽

Resting Metabolic Rate ◽

Urine Volume ◽

Body Weight Loss ◽

The Body ◽

Male Rats ◽

Calorie Intake ◽

Isocaloric Diets

With adult male rats, experiments were carried out to ascertain the different effects, if any, of isocaloric diets high in carbohydrate, fat, or protein fed in restricted amounts of 9 g per rat per day on body weight loss and composition. It was observed that the nature of the diet did not alter rate, amount, or composition of body weight loss when fed in restricted amount for a period of 12 days. Further, the nature of the diet did not alter significantly the following parameters during restriction: water intake, urine volume, resting metabolic rate, spontaneous activity, urine and feces calorie values. In an experiment with hypothalamic-obese rats, the body weight loss and composition were not significantly different among the dietary-restricted groups. An important observation in this experiment was that as body fat decreased markedly owing to restricted feeding, body water increased markedly and counterbalanced approximately 60% of the potential weight loss due to the decrease in body fat. Our reported observations do not support the hypothesis that the composition of the diet may determine the rate and amount of body weight loss as a consequence of restricted food intake. They do support the hypothesis that the calorie intake, not the nature of the source of calories, determines the rate and amount of weight loss, at least for relatively short periods of food restriction.

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Dietary Exposure to Oxidized Frying Oil from Fetus to Adulthood Suppresses Male Reproductive Development by Altering Testicular Cholesterol and Testosterone Homeostasis in Sprague Dawley Rats

Journal of Nutrition ◽

10.1093/jn/nxaa091 ◽

2020 ◽

Vol 150 (7) ◽

pp. 1713-1721

Author(s):

Hai-Ping Wu ◽

Yu-Shun Lin ◽

Chi-Fen Chang ◽

Shui-Yuan Lu ◽

Pei-Min Chao

Keyword(s):

Weight Loss ◽

Body Weight ◽

Soybean Oil ◽

Body Weight Loss ◽

Reproductive Development ◽

Frying Oil ◽

Female Rats ◽

Male Rats ◽

Sprague Dawley ◽

Sprague Dawley Rats

ABSTRACT Background Dietary frying oil may have endocrine-disrupting effects, as a feminization effect was observed in cohorts of C57BL/6J male mice fetuses from dams consuming oxidized frying oil (OFO) during pregnancy. Objective The aim of present study was to test the hypothesis that OFO is an anti-androgen. Methods In experiment 1, male progeny of Sprague Dawley female rats fed fresh oil or an OFO diet (10 g fat/100 g, from fresh or 24-h–fried soybean oil; [control diet (C) and OFO groups, respectively] from midgestation through lactation were studied. Pups were weaned at 3 wk of age and then consumed their mothers’ diet until 9 wk of age. In addition, a group of dams and pups that consumed a high-fat diet (HF; 10 g fried and 20 g fresh soybean oil/100 g) was included to counteract body-weight loss associated with OFO ingestion. Indices of male reproductive development and testosterone homeostasis were measured. In experiment 2, male rats were allocated to C and OFO groups (treated as above) and indices of male fertility compared at 9–10 wk of age. Results In experiment 1, final body weights of the HF group were lower (17%) than the C group but higher (14%) than the OFO group (P < 0.0001 for each). In addition to abnormalities in seminiferous tubules, HF and OFO groups did not differ from one another, but, compared with the C group, had delayed preputial separation (4.9 d) and reductions in serum testosterone concentrations (17–74%), anogenital distance (8–20%), weights of androgen-dependent tissues (8–30%), testicular testosterone and cholesterol concentrations (30–40%), and mRNA levels of genes involved in steroidogenesis and cholesterol homeostasis (30–70%). In experiment 2, OFO-exposed males had 20% lower sperm motility (P < 0.05); however, when mated to normal females, pregnancy rates and litter sizes did not differ between OFO and C groups. Conclusions The anti-androgenic effect of OFO in Sprague Dawley rats was attributed to decreased testicular concentrations of cholesterol (testosterone precursor) and not body-weight loss.

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Hydroxycitrate Has Long-Term Effects on Feeding Behavior, Body Weight Regain and Metabolism after Body Weight Loss in Male Rats

Journal of Nutrition ◽

10.1093/jn/132.7.1977 ◽

2002 ◽

Vol 132 (7) ◽

pp. 1977-1982 ◽

Cited By ~ 25

Author(s):

Monika Leonhardt ◽

Wolfgang Langhans

Keyword(s):

Weight Loss ◽

Body Weight ◽

Feeding Behavior ◽

Weight Regain ◽

Body Weight Loss ◽

Male Rats ◽

Long Term Effects

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Effects of prior or concurrent food restriction on amylin-induced changes in body weight and body composition in high-fat-fed female rats

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00395.2007 ◽

2007 ◽

Vol 293 (4) ◽

pp. E1112-E1117 ◽

Cited By ~ 16

Author(s):

Jonathan D. Roth ◽

Heather Hughes ◽

Todd Coffey ◽

Holly Maier ◽

James L. Trevaskis ◽

...

Keyword(s):

Weight Loss ◽

Body Weight ◽

Food Restriction ◽

Body Weight Gain ◽

Body Weight Loss ◽

Specific Weight ◽

Female Rats ◽

Male Rats ◽

High Fat ◽

Ad Libitum

Amylin infusion reduces food intake and slows body weight gain in rodents. In obese male rats, amylin (but not pair feeding) caused a preferential reduction of fat mass with protein preservation despite equal body weight loss in amylin-treated (fed ad libitum) and pair-fed rats. In the present study, the effect of prior or concurrent food restriction on the ability of amylin to cause weight loss was evaluated. Retired female breeder rats were maintained on a high-fat diet (40% fat) for 9 wk. Prior to drug treatment, rats were either fed ad libitum or food restricted for 10 days to lose 5% of their starting body weight. They were then subdivided into treatment groups that received either vehicle or amylin (100 μg·kg−1·day−1 via subcutaneous minipump) and placed under either a restricted or ad libitum feeding schedule (for a total of 8 treatment arms). Amylin 1) significantly reduced body weight compared with vehicle under all treatment conditions, except in always restricted animals, 2) significantly decreased percent body fat in all groups, and 3) preserved lean mass in all groups. These results indicate that amylin's anorexigenic and fat-specific weight loss properties can be extended to a variety of nutritive states in female rats.

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