Effects of Dietary Lactose on Long‐term High‐fat‐diet‐induced Obesity in Rats

Abstract

GOSEKI-SONE, MASAE, RIEKO MARUYAMA, NATSUKO SOGABE, AND TAKAYUKI HOSOI. Effects of dietary lactose on long-term high-fat-diet-induced obesity in rats. Obesity. 2007;15:2605-2613. Objective: In this study, we examined the effects of lactose on long-term high-fat-diet-induced obesity in rats. Research Methods and Procedures:A total of 112 Sprague-Dawley strain female rats (6 weeks old) were divided into four groups: a basic control diet group (Cont), 10% lactose diet group (Lac), high-fat diet group (Fat), and high-fat with 10% lactose diet group (FatϩLac). After 0, 7, 14, and 84 days from starting the experimental diet, the animals were fasted overnight and killed by bleeding from the abdominal aorta under anesthesia (n ϭ 8 or 9/group). Results: After 84 days, the addition of lactose to the high-fat diet decreased the final body weight, body weight gain, fat accumulation, and the levels of serum leptin, serum triglycerides, and serum glucose significantly (p Ͻ 0.05). Although there was no significant difference in the levels of serum calcium and phosphorus between the Fat and FatϩLac groups, lumbar vertebral bone mineral density was significantly higher in the FatϩLac group than in the Cont group on Day 82. Interestingly, the level of serum 1␣, 25-dihydroxyvitamin D 3 in the FatϩLac group on Day 84 was reduced by 74% compared with the Fat group (p Ͻ 0.01), while there was no significant difference in serum parathyroid hormone levels between the Fat and FatϩLac groups. Discussion: This is the first study to suggest that the addition of lactose to a long-term high-fat diet may regulate not only calcium metabolism but also fat deposition. Further studies on the mechanism of dietary lactose in the regulation of adiposity would provide valuable data for the prevention of long-term high-fat-diet-induced obesity.

Effects of diet-induced obesity and voluntary wheel running on the microstructure of the murine distal femur

“…However, the effects of body mass on the skeleton remain controversial although well documented in obese subjects in previous studies [35,36]. Some studies have shown that obese subjects have weaker bone to bear their over-weight body mass compared to normal counterparts in both humans and animals [37,38]. In our study, after adjusting for body mass (unpublished data), no significant differences in bone traits between the obese and normal weight mice were found.…”

Development of a novel chronic kidney disease mouse model to evaluate the progression of hyperphosphatemia and associated mineral bone disease

“…Morphometric parameters of the distal metaphysis of the femur were measured as described previously 63 , with the following parameters calculated: bone volume (BV), tissue volume (TV), bone mineral density (BMD), cortical mineral density (CMD), cortical mineral volume (CMV), and bone volume fraction (BV/TV).…”

A high-fat diet decreases AMPK activity in multiple tissues in the absence of hyperglycemia or systemic inflammation in rats

“…After acclimatization, half the rats were fed a standard chow diet (3 kcal/g, 14 % calories from fat, 32 % calories from protein, 54 % calories from carbohydrate; 8604 Teklad rodent diet, Harlan) and the other half fed a high-fat diet (5.25 kcal/g, 60 % calories from fat, 20 % calories from protein, 20 % calories from carbohydrate; Open Source Diets D12492) for 18 weeks. Eighteen weeks was chosen based on the different lengths of time used in previous studies [2, 15, 17]. Each rat was singly caged and had unrestricted access to food and water.…”