scholarly journals Low Calcium-Phosphate Intakes Modulate the Low-Protein Diet-Related Effect on Peak Bone Mass Acquisition: A Hormonal and Bone Strength Determinants Study in Female Growing Rats

Endocrinology ◽  
2014 ◽  
Vol 155 (11) ◽  
pp. 4305-4315 ◽  
Author(s):  
C. Fournier ◽  
R. Rizzoli ◽  
P. Ammann
Keyword(s):  
Bone Mass ◽  
Peak Bone Mass ◽  
Mineral Content ◽  
Skeletal Growth ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Hepatic Gene Expression ◽  
Mrna Levels ◽  
Casein Diet ◽  
Low Protein

Abstract Peak bone mass acquisition is influenced by environmental factors including dietary intake. A low-protein diet delays body and skeletal growth in association with a reduction in serum IGF-1 whereas serum FGF21 is increased by selective amino acid deprivation. Calcium (Ca) and phosphorous (P) are also key nutrients for skeletal health, and inadequate intakes reduce bone mass accrual in association with calciotropic hormone modulation. Besides, the effect of calcium supplementation on bone mass in prepubertal children appears to be influenced by protein intake. To further explore the interaction of dietary protein and Ca-P intake on bone growth, 1-month-old female rats were fed with an isocaloric 10%, 7.5%, or 5% casein diet containing normal or low Ca-P for an 8-week period (6 groups). Changes in tibia geometry, mineral content, microarchitecture, strength, and intrinsic bone quality were analyzed. At the hormonal level, serum IGF-1, fibroblast growth factor 21 (FGF21), PTH, 1,25-dihydroxyvitamin D3 (calcitriol), and FGF23 were investigated as well as the Ghr hepatic gene expression. In normal dietary Ca-P conditions, bone mineral content, trabecular and cortical bone volume, and bone strength were lower in the 5% casein group in association with a decrease in serum IGF-1 and an increase in FGF21 levels. Unexpectedly, the low-Ca-P diet attenuated the 5% casein diet-related reduction of serum IGF-1 and Ghr hepatic gene expression, as well as the low-protein diet-induced decrease in bone mass and strength. However, this was associated with lower cortical bone material level properties. The low-Ca-P diet increased serum calcitriol but decreased FGF23 levels. Calcitriol levels positively correlated with Ghr hepatic mRNA levels. These results suggest that hormonal modulation in response to a low-Ca-P diet may modify the low-protein diet-induced effect on Ghr hepatic mRNA levels and consequently the impact of low protein intakes on IGF-1 circulating levels and skeletal growth.

Effects of a Low-Protein Diet on Glomerular Endothelin Family Gene Expression in Experimental Focal Glomerular Sclerosis

1995 ◽  
Vol 88 (1) ◽  
pp. 29-37 ◽  
Author(s):  
Tsukasa Nakamura ◽  
Mitsumine Fukui ◽  
Isao Ebihara ◽  
Shiori Osada ◽  
Toshimasa Takahashi ◽  
...  
Keyword(s):  
Protein Diet ◽  
Low Protein Diet ◽  
Endothelin Receptors ◽  
Glomerular Sclerosis ◽  
Standard Diet ◽  
Mrna Levels ◽  
Puromycin Aminonucleoside ◽  
Endothelin 1 ◽  
Low Protein ◽  
Focal Glomerular Sclerosis

1. The present study was designed to assess whether glomerular expression of mRNAs for endothelin-1 and endothelin-3, as well as endothelin receptors A and B is affected by a low-protein diet during the course of focal glomerular sclerosis. 2. Focal glomerular sclerosis was induced in rats by injection of puromycin aminonucleoside on days 0, 27, 34 and 41 in conjunction with unilateral nephrectomy on day 22. Control rats were subjected to nephrectomy or sham operation on day 22. 3. Animals were divided into six groups. In group 1, the puromycin aminonucleoside-injected rats were fed a standard diet containing 22% protein. In group 2, the puromycin aminonucleoside-injected rats were fed a low-protein diet containing 6% protein, which was initiated on the day of the first puromycin aminonucleoside injection. In group 3, the nephrectomized rats without puromycin aminonucleoside were fed a standard diet. In group 4, the nephrectomized rats without puromycin aminonucleoside were fed a low-protein diet. In group 5, the sham-operated rats were fed a standard diet. In group 6, the sham-operated rats were fed a low-protein diet. 4. The percentage of sclerotic glomeruli in group 1 rats increased markedly with time, reaching 77% on day 80. 5. The glomerular mRNA levels for endothelin-1 and endothelin receptors A and B increased significantly as glomerular sclerosis progressed, whereas no endothelin-3 mRNA was detected in the glomeruli of any group. 6. The endothelin-1 production in isolated glomeruli from group 1 increased significantly as glomerular sclerosis progressed. 7. In group 2, the low-protein diet reduced the prevalence of glomerular sclerosis, attenuated the rise in mRNA levels for endothelin-1 and endothelin receptors A and B and reduced endothelin-1 production in glomeruli from rats with focal glomerular sclerosis. 8. These data indicate that increases in glomerular endothelin-1 and endothelin receptor mRNA levels are associated with the development of puromycin aminonucleoside-induced glomerular sclerosis. These effects are blunted by administration of a low-protein diet.

VITAMIN A AND CAROTENE UTILIZATION IN PROTEIN-DEPRIVED RATS

1963 ◽  
Vol 41 (1) ◽  
pp. 543-549 ◽  
Author(s):  
J. Mathews ◽  
G. H. Beaton
Keyword(s):  
Vitamin A ◽  
Serum Vitamin ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Separate Study ◽  
Casein Diet ◽  
Significant Lowering ◽  
Low Protein ◽  
Protein Free Diet ◽  
Β Carotene

Maintenance of rats on a protein-free, but not a 4% casein, diet produced a significant lowering of serum vitamin A. This effect was seen in rats deprived of vitamin A or provided with 90 μg of the vitamin twice weekly. In a separate study, rats maintained on 4% and 20% casein diets were depleted of vitamin A. They were then given 6 or 12 μg of vitamin A or 24 μg of carotene per day. The blood vitamin A response to administered vitamin A was not affected. Rats fed the low-protein diet exhibited only about one half of the serum vitamin A response to administered carotene as did those fed the 20% casein diet. Carotene failed to maintain liver vitamin A content in rats fed the low-protein diet. The results suggested that the absorption/conversion of β-carotene is impaired in rats maintained on a 4% protein diet. When rats were fed a protein-free diet the mobilization of vitamin A from the liver, or transport of the vitamin was also impaired.

scholarly journals The growth and development of rats given a low-protein diet

1972 ◽  
Vol 27 (3) ◽  
pp. 527-536 ◽  
Author(s):  
J. W. T. Dickerson ◽  
P. C. R. Hughes ◽  
P. A. McAnulty
Keyword(s):  
Body Weight ◽  
Brain Stem ◽  
Dna Content ◽  
The Body ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Casein Diet ◽  
Control Value ◽  
Low Protein ◽  
The Brain

1. Weanling (24-d-old) rats of a black and white hooded strain were allowed free access for 28 d to a diet containing 5% casein supplemented with methionine, and sucrose as the carbohydrate. Controls were fed on a 25% casein diet with a corresponding reduction in sucrose. Animals given the deficient diet were killed either at 52 d of age or after subsequent rehabilitation on the 25% casein diet when aged 140 d. These animals were compared with controls killed at these two ages and at the start of the experiment.2. The skeletons were X-rayed, skeletal maturity was determined according to a scoring system, and various bones were measured. The forebrain and cerebellum were analysed for cholesterol and DNA and the brain stem for cholesterol only. The DNA content of the paired quadriceps muscles and the livers was also determined.3. On the low-protein diet the body-weight rose by 7 g compared with the control value of 115 g. On rehabilitation, the body-weight of the previously malnourished group showed the expected growth spurt, but failed to attain that of the controls at 140 d.4. With the exception of the pelvis width, all the bones grew a little during the period on the low-protein diet. After rehabilitation, the hind limb, pelvis, iliac and spine lengths and the bi-iliac width remained smaller than these measurements in the corresponding controls, whereas there was no difference in the length of the fore limb, width of the pelvis or in the bone maturity score.5. The forebrains and cerebellums of the malnourished rats did not increase in weight, whereas some increase occurred in the brain stem. The concentration of cholesterol in the forebrains of the deficient animals was the same as that in controls of the same age, but on rehabilitation the concentration did not rise to the control value. The concentration of cholesterol in the cerebellum and brain stem of the deficient rats was lower than in controls of the same age but, whereas that in the cerebellum attained an almost normal level on rehabilitation, that in the brain stem remained significantly lower. The low-protein diet prevented the normal increase in cerebellum DNA and the amount remained low in the rehabilitated animals.6. The experimental diet caused a complete cessation of growth of the quadriceps muscles, and even after rehabilitation they weighed less than their controls. The DNA content, however, was not significantly lower.7. The low-protein diet did not permanently affect either the weight or DNA content of the liver.

scholarly journals Maternal Moderate Physical Training during Pregnancy Attenuates the Effects of a Low-Protein Diet on the Impaired Secretion of Insulin in Rats: Potential Role for Compensation of Insulin Resistance and Preventing Gestational Diabetes Mellitus

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Carol Góis Leandro ◽  
Marco Fidalgo ◽  
Adriano Bento-Santos ◽  
Filippe Falcão-Tebas ◽  
Diogo Vasconcelos ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Insulin Resistance ◽  
Insulin Secretion ◽  
Physical Training ◽  
Potential Role ◽  
Isolated Islets ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Casein Diet ◽  
Low Protein

The effects of pregestational and gestational low-to-moderate physical training on insulin secretion in undernourished mothers were evaluated. Virgin female Wistar rats were divided into four groups as follows: control (C,n=5); trained (T,n=5); low-protein diet (LP,n=5); trained with a low-protein diet (T + LP,n=5). Trained rats ran on a treadmill over a period of 4 weeks before mate (5 days week−1and 60 min day−1, at 65% ofVO2max). At pregnancy, the intensity and duration of the exercise were reduced. Low-protein groups were provided with an 8% casein diet, and controls were provided with a 17% casein diet. At third day after delivery, mothers and pups were killed and islets were isolated by collagenase digestion of pancreas and incubated for a further 1 h with medium containing 5.6 or 16.7 mM glucose. T mothers showed increased insulin secretion by isolated islets incubated with 16.7 mM glucose, whereas LP group showed reduced secretion of insulin by isolated islets when compared with both C and LP + T groups. Physical training before and during pregnancy attenuated the effects of a low-protein diet on the secretion of insulin, suggesting a potential role for compensation of insulin resistance and preventing gestationaldiabetes mellitus.

The effect of a low-protein diet in pregnancy on offspring renal calcium handling

2007 ◽  
Vol 293 (2) ◽  
pp. R759-R765 ◽  
Author(s):  
Nick Ashton ◽  
Saleh H. Al-Wasil ◽  
Helen Bond ◽  
Jacqueline L. Berry ◽  
John Denton ◽  
...  
Keyword(s):  
Bone Mass ◽  
Atpase Activity ◽  
Protein Diet ◽  
Calcium Handling ◽  
Low Protein Diet ◽  
Calcium Excretion ◽  
Total Body Calcium ◽  
Low Protein ◽  
Calcitropic Hormones ◽  
Calbindin D

Low birth weight humans and rats exposed to a low-protein diet in utero have reduced bone mineral content. Renal calcium loss during the period of rapid skeletal growth is associated with bone loss. Because young rats exposed to low protein display altered renal function, we tested the hypothesis that renal calcium excretion is perturbed in this model. Pregnant Wistar rats were fed isocalorific diets containing either 18% (control) or 9% (low) protein throughout gestation. Using standard renal clearance techniques, Western blotting for renal calcium transport proteins, and assays for Na+-K+-ATPase activity and serum calcitropic hormones, we characterized calcium handling in 4-wk-old male offspring. Histomorphometric analyses of femurs revealed a reduction in trabecular bone mass in low-protein rats. Renal calcium (control vs. low protein: 10.4 ± 2.1 vs. 27.6 ± 4.5 nmol·min−1·100 g body wt−1; P < 0.01) and sodium excretion were increased, but glomerular filtration rate was reduced in low-protein animals. Total plasma calcium was reduced in low-protein rats ( P < 0.01), but ionized calcium, serum calcitropic hormone concentrations, and total body calcium did not differ. There was no significant change in plasma membrane Ca2+-ATPase pump, epithelial calcium channel, or calbindin-D28K expression in low-protein rat kidneys. However, Na+-K+-ATPase activity was 36% lower ( P < 0.05) in low-protein rats. These data suggest that the hypercalciuria of low-protein rats arises through a reduction in passive calcium reabsorption in the proximal tubule rather than active distal tubule uptake. This may contribute to the reduction in bone mass observed in this model.

scholarly journals The 17β-oestradiol treatment minimizes the adverse effects of protein restriction on bone parameters in ovariectomized Wistar rats

2019 ◽  
Vol 8 (12) ◽  
pp. 573-581 ◽  
Author(s):  
Victoria P. de Quadros ◽  
Natalia Tobar ◽  
Lais R. Viana ◽  
Rogerio W. dos Santos ◽  
Paulo H. M. Kiyataka ◽  
...  
Keyword(s):  
Adverse Effects ◽  
Bone Mass ◽  
Wistar Rats ◽  
Protein Restriction ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Hormone Deficiency ◽  
Mineral Density ◽  
Bone Parameters ◽  
Low Protein

Objectives Insufficient protein ingestion may affect muscle and bone mass, increasing the risk of osteoporotic fractures in the elderly, and especially in postmenopausal women. We evaluated how a low-protein diet affects bone parameters under gonadal hormone deficiency and the improvement led by hormone replacement therapy (HRT) with 17β-oestradiol. Methods Female Wistar rats were divided into control (C), ovariectomized (OVX), and 17β-oestradiol-treated ovariectomized (OVX-HRT) groups, which were fed a control or an isocaloric low-protein diet (LP; 6.6% protein; seven animals per group). Morphometric, serum, and body composition parameters were assessed, as well as bone parameters, mechanical resistance, and mineralogy. Results The results showed that protein restriction negatively affected body chemical composition and bone metabolism by the sex hormone deficiency condition in the OVX group. The association between undernutrition and hormone deficiency led to bone and muscle mass loss and increased the fragility of the bone (as well as decreasing relative femoral weight, bone mineral density, femoral elasticity, peak stress, and stress at offset yield). Although protein restriction induced more severe adverse effects compared with the controls, the combination with HRT showed an improvement in minimizing these damaging effects, as it was seen that HRT had some efficacy in maintaining muscle and bone mass, preserving the bone resistance and minimizing some deleterious processes during the menopause. Conclusion Protein restriction has adverse effects on metabolism, leading to more severe menopausal symptoms, and HRT could minimize these effects. Therefore, special attention should be given to a balanced diet during menopause and HRT. Cite this article: Bone Joint Res 2019;8:573–581.

scholarly journals Maternal low-protein diet-induced delayed reflex ontogeny is attenuated by moderate physical training during gestation in rats

2011 ◽  
Vol 107 (3) ◽  
pp. 372-377 ◽  
Author(s):  
Filippe Falcão-Tebas ◽  
Adriano Bento-Santos ◽  
Marco Antônio Fidalgo ◽  
Marcelus Brito de Almeida ◽  
José Antônio dos Santos ◽  
...  
Keyword(s):  
Physical Training ◽  
Virgin Female ◽  
Somatic Growth ◽  
Protein Diet ◽  
Physical Feature ◽  
Low Protein Diet ◽  
Postnatal Life ◽  
Casein Diet ◽  
Low Protein ◽  
Female Wistar Rats

We evaluated the effects of moderate- to low-intensity physical training during gestation on reflex ontogeny in neonate rats whose mothers were undernourished. Virgin female Wistar rats were divided into four groups as follows: untrained (NT, n 7); trained (T, n 7); untrained with a low-protein diet (NT+LP, n 7); trained with a low-protein diet (T+LP, n 4). Trained rats were subjected to a protocol of moderate physical training on a treadmill over a period of 4 weeks (5 d/week and 60 min/d, at 65 % of VO2max). After confirming the pregnancy, the intensity and duration of the exercise were reduced. Low-protein groups were provided with an 8 % casein diet, and controls were provided with a 17 % casein diet. Their respective offspring were evaluated (during the 10th–17th days of postnatal life) in terms of physical feature maturation, somatic growth and reflex ontogeny. Pups born to mothers provided with the low-protein diet during gestation and lactation showed delayed physical feature and reflex maturation and a deficit in somatic growth when compared with controls. However, most of these deficiencies were attenuated in pups of undernourished mothers undergoing training. In conclusion, physical training during gestation attenuates the effects of perinatal undernutrition on some patterns of maturation in the central nervous system during development.

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