Influence of hydrocortisone acetate of the longissimus dorsi muscle during gestation of rats

The evolution in detail of the N retention during gestation was studied, dividing it in short periods of time, and how that retention affects Longissimus dorsi muscle. Simultaneously, the same study in pregnant rats treated with hydrocortisone acetate was done. During gestation N balance maintains high values that tend to increase at days 18 to 21. The greatest metabolic utilization of the N dietary corresponds to this period in which the percentage of the N retained in relation to the N absorbed is markedly higher than in previous days of gestation. In spite of the excellent quality and adequate concentration of protein in the diet, the administration of 4 mg/100 g weight and day of hydrocortisone acetate maintains the pregnant rat in a negative balance until day 18, as a consequence of the decrease in food intake and faecal and urinary N losses. From day 18 to day 21 of gestation the balance of N increases and the metabolic utilization of the dietary N is similar between pregnant rats injected with NaCl 0.9% and pregnant rats injected with hydrocortisone acetate. The Longissimus dorsi normal growth pattern (in relation to weight and N content) in young adult rats is not modified by gestation. The catabolic effects of hydrocortisone acetate on Longissimus dorsi muscle in pregnant rats can be observed from day 9 of treatment. The longer the treatment the higher the effect is.     

Influence of hydrocortisone acetate on the magnesium metabolism during pregnancy in rats

The influence of hydrocortisone acetate i.m. administered (4 mg/100 g of body weight and day) to pregnant rats, on magnesium nutritive utilization and bone magnesium content in the mothers and its possible repercussions on newborn Mg content are studied. Hydrocortisone acetate treatment significantly reduces Mg content in the litters, which can be explained on the basis of a significant decrease in both the magnesium absorption and retention by the hormone-treated mothers. The mobilization of femoral magnesium and the increase in the urinary excretion of the cation provoke a reduction in magnesium retention in the treated mothers.     

Influence of gestation and hydrocortisone-acetate treatment on the nutritive utilization of protein

The effect of pregnancy and of cortisol on the digestive and metabolic utilization of protein in Wistar rats was studied. The cortisol is i.m. administered during 21 days in a pharmacological dose (4 mg/100 g weight per day) to female Wistar rats. Pregnancy is observed to increase and cortisol to decrease significantly the food intake (g dry matter/rat per day); the intake of nitrogen follows the same pattern. Pregnancy significantly increases the weight of both groups: pregnant rats as comparison to non-pregnant rats saline injected and pregnant rats cortisol-treated in relation to the animals pregnant but not hormone-treated. The increase being greater in the last 5 days of pregnancy. Cortisol in the pregnant and non pregnant rats considerably reduces the weight. The protein absorption is unaltered by pregnancy but is diminished by the effect of cortisol. Pregnancy increases the balance of nitrogen in both sets of rats; the increase being significantly greater in the last period of pregnancy. When administered to non pregnant rats, cortisol produces a negative balance of nitrogen. The protein of good quality (casein + 5% DL-methionine at a level of 12%) partially equalizes the negative effect of cortisol in spite of the long treatment and high doses used.     

Effect of phosphorus intake on calcium homeostasis and bone tissue status in rats receiving hydrocortisone

The increase of phosphorus content up to 1.2-1.8% in the diet (the calcium/phosphorus ratio 1:2 or 1:3) accelerates the development and raises the rate of hypocalcemia and osteoporosis in rats administered pharmacological doses of hydrocortisone (3.5 mg per 100 g bw a day for 2 or 4 weeks). The decrease of phosphorus content to 0.3% (calcium-phosphorus 1:0.5) essentially retards the development of these disturbances and reduces their severity, which points to the advisability of clinical trials of the diet with phosphorus limitation as means of the prophylaxis of calcium homeostasis and bone alterations during long-term administration of glucocorticoids and in endogenous hypercorticoidism.     

Influence of an inhibitor of monoaminooxidase (nialamide) on the serum levels, urinary excretion and plasma clearance of urea, uric acid and creatinine in adult and growing rats

Serum levels, urinary excretion and plasma clearance of urea, uric acid and creatinine were studied in adult (230 g) and growing (75 g) rats under the influence of nialamide (an IMAO) administered in daily doses of 20 mg/100 g diet during 15 or 30 days in adults and 10 mg/100 g diet during 15 days in growing rats. A pair feeding design was used in both ages. Serum levels of urea rose in adult rats fed nialamide for 30 days while urinary excretion decreased. No change in serum levels were noted in growing rats although urinary excretion showed a net increase. Serum uric acid levels were increased in adult female rats given nialamide for 30 days, while urinary excretion fell in both sexes. Growing rats showed a drop in urinary excretion of uric acid. Serum creatinine levels were unchanged in adult and growing rats after treatment with nialamide, although a marked increase was recorded in urinary excretion in both groups.     

Comparative study of the influence of an inhibitor of monoaminooxidase (nialamide) on the calcium and phosphorus metabolism in slow and fast-growing rats

Nialamide was supplied to slow-growing animals in doses of 20 mg/100 g of diet for 15 or 30 days. The dose for fast-growing animals was 10 mg/100 g of diet. The digestive utilization of calcium and phosphorus decreases significantly when adult slow-growing rats receive the drug for 30 days. This fall is already important in fast-growing rats when they receive nialamide for only 15 days. In the same way the falls in the retention of calcium and phosphorus in adult rats are only evident when the period of treatment is through 30 days, even females being in negative balance of phosphorus. The amount of calcium retained decreases significantly in fast-growing rats and so does phosphorus impressively after only 15 days of treatment.     

Effect of 1,25-dioxycholecalciferol and 24,25-dioxycholecalciferol on calcium homeostasis in rats given hydrocortisone in the diet with various phosphorus contents

High content of phosphorus in the diet (1.8% of phosphorus in the diet, Ca:P ratio 1:3) accelerated the development of hypocalcemia and osteoporosis and increased their degree in rats which received hydrocortisone (3.5 mg/10 g bw a day for 4 weeks). Reduction of phosphorus consumption to 0.3% (Ca:P ration 1:0.5) essentially retarded the development of these disturbances and lowered their degree. The use of 1,25-dioxycholecalciferol and 24,25-dioxycholecalciferol in doses of 0.03 and 1.5 mg, respectively promoted the normalization of phosphorus-calcium metabolism and improvement of the status of the osseous tissue in rats given hydrocortisone coupled with both diets. The most beneficial affect on calcium homeostasis in exogenous hypercorticoidism was attained with the use of active metabolites of vitamin D3 coupled with the diet with a low phosphorus content (0.3%). In this case there was a complete normalization of the density of the osseous tissue and of the calcium and phosphorus content. In view of this fact it is advisable to combine active metabolites of vitamin D3 and the diet with a low phosphorus content.     

Periparturient effects of feeding a low dietary cation-anion difference diet on acid-base, calcium, and phosphorus homeostasis and on intravenous glucose tolerance test in high-producing dairy cows

Feeding rations with low dietary cation-anion difference (DCAD) to dairy cows during late gestation is a common strategy to prevent periparturient hypocalcemia. Although the efficacy of low-DCAD rations in reducing the incidence of clinical hypocalcemia is well documented, potentially deleterious effects have not been explored in detail. The objective of the study presented here was to determine the effect of fully compensated metabolic acidosis on calcium and phosphorus homeostasis, insulin responsiveness, and insulin sensitivity as well as on protein metabolism. Twenty multiparous Holstein-Friesian dairy cows were assigned to 1 of 2 treatment groups and fed a low-DCAD ration (DCAD = −9 mEq/100 g, group L) or a control ration (DCAD = +11 mEq/100 g, group C) for the last 3 wk before the expected calving date. Blood and urine samples were obtained periodically between 14 d before to 14 d after calving. Intravenous glucose tolerance tests and 24-h volumetric urine collection were conducted before calving as well as 7 and 14 d postpartum. Cows fed the low-DCAD ration had lower urine pH and higher net acid excretion, but unchanged blood pH and bicarbonate concentration before calving. Protein-corrected plasma Ca concentration 1 d postpartum was higher in cows on the low-DCAD diet when compared with control animals. Urinary Ca and P excretion was positively associated with urine net acid excretion and negatively associated with urine pH. Whereas metabolic acidosis resulted in a 6-fold increase in urinary Ca excretion, the effect on renal P excretion was negligible. A more pronounced decline of plasma protein and globulin concentration in the periparturient period was observed in cows on the low-DCAD diets resulting in significantly lower total protein and globulin concentrations after calving in cows on low-DCAD diets. Intravenous glucose tolerance tests conducted before and after calving did not reveal group differences in insulin response or insulin sensitivity. Our results indicate that fully compensated metabolic acidosis increased the Ca flux resulting in increased urinary calcium excretion before calving and increased plasma Ca concentration on the day after calving, whereas the effect on P homeostasis was unlikely to be clinically relevant. The clinical relevance of the effect of metabolic acidosis on the plasma protein and globulin concentration is unclear but warrants further investigation.     

Effects of vitamin D metabolites on indicators of protein, phosphorus and calcium metabolism in children with chronic renal failure

Amino acid analysis and investigation of nitrogen, calcium and phosphorus balance were done in two groups of patients with renal failure and osteodystrophy on vitamin D metabolites and analogues treatment. The results of the investigation confirm vitamin D metabolites influence on free amino acid metabolism and on nitrogen, calcium, phosphorus balance. We observed significant decreases of blood amino acids and good influence on renal osteodystrophy in patients treated with vitamin D metabolites. Vitamin D metabolites didn't influence retention, urinary and fecal excretion of endogenous nitrogen in patients with renal failure.     

Long‐chain fatty acid supplemented infant formula does not influence calcium and magnesium bioavailability in weanling rats

The influence of infant formula supplementation with long‐chain‐polyunsaturated fatty acids (LCPUFA) on calcium and magnesium bioavailability was assessed in rats. Two test diets containing a plain, unsupplemented (PF) or supplemented (SF) infant formula as the fat source and a control diet (C) were administered to weaning rats and food intake and body weight gain were monitored for 28 days. In order to assess calcium and magnesium bioavailability, during the last week faeces and urine were collected and apparent absorption and retention were calculated. Food intake and body weight showed no significant differences between PF and SF but were lower in both groups compared with C. Calcium and magnesium intake did not differ between PF and SF, although both parameters were lower compared with C. Calcium absorption efficiency in PF and SF was significantly higher than in C. However, both groups showed higher urinary calcium excretion and thus no differences were observed in calcium retention. Magnesium absorption efficiency was also significantly higher in PF and SF compared with C, but magnesium absorption was significantly lower in SF compared with PF and C. Nevertheless, urinary magnesium excretion and magnesium retention were similar in the three groups. The consumption of a diet containing an infant formula supplemented with LCPUFA compared with the plain formula does not affect calcium and magnesium bioavailability in rats. Copyright © 2005 Society of Chemical Industry     

Effects of diets containing oils from repeated frying on magnesium absorption

Olive oil, sunflower oil and palm olein were used in repeated potato fryings until the oils reached the limit of 25% of polar compounds allowed by law. Six groups of rats, over 28 days, were fed diets containing 8% of: olive oil; olive oil from 69 fryings; sunflower oil; sunflower oil from 48 frying; palm olein, and palm olein from 80 fryings. Body weight and food intake were monitored weekly, during days 21–28 faeces and urine were collected and finally blood and carcasses were also collected and stored. No significant differences were observed in food intake and body weight among the six groups of animals. The type of oil did not modify magnesium intake, the urinary and faecal excretion of this mineral nor its apparent absorption or retention. The consumption of oils from frying, however, induced an increase in apparent magnesium absorption due to a decrease in faecal magnesium excretion, but magnesium retention did not vary owing to the increase in urinary losses. Serum magnesium and magnesium contents and concentrations in carcasses were unaffected. Therefore, it was concluded that the consumption of used frying oils enhances magnesium absorption, independently from the type of oil, although magnesium retention is not affected due to a an elevation of urinary excretion. © 1999 Society of Chemical Industry     

Remodeling and angiotensin II responses of the uterine arcuate arteries of pregnant rats are altered by low- and high-sodium intake

Lowering and increasing sodium intake in pregnant rats evoke opposite changes in renin-angiotensin-aldosterone system (RAAS) activity and are associated with alterations of blood volume expansion. As augmented uterine blood flow during gestation is linked to increased circulatory volume, we wanted to determine if low- and high-sodium intakes affect the mechanical properties and angiotensin II (AngII) responses of the uterine vasculature. Non-pregnant and pregnant rats received a normal sodium (0.22% Na+) diet. On the 15th day of gestation some animals were moved to a low-sodium (0.03%) diet, whereas others were given NaCl supplementation as beverage (saline, 0.9% or 1.8%) for 7 days. All rats were killed after 7 days of treatment (eve of parturition). Uterine arcuate arteries (>100 microm) were set up in wire myographs under a tension equivalent to 50 mmHg transmural pressure. The pregnancy-associated increase in diameter of the uterine arteries was significantly attenuated on the low-sodium diet and 1.8% NaCl supplementation. The arcuate arteries of non-pregnant rats on the low-sodium diet showed markedly increased responses to AngII and phenylephrine (Phe). Pregnancy also resulted in heightened responses to AngII and Phe that were significantly reduced for the former agent in rats on the low-sodium diet. Sodium supplementation of non-pregnant rats did not affect the reactivity of the uterine arteries to AngII, but significantly reduced the effect of Phe (1 micromol/l). High salt also significantly diminished the elevated responses to AngII in the arteries of pregnant animals. It was observed that altered sodium intake affects the mechanical and reactive properties of the uterine arcuate arteries more importantly in pregnant than in non-pregnant rats. Low-salt intake similarly affected the reactivity of the uterine arcuate arteries to AngII and Phe, whereas high-salt intake more specifically affected AngII responses. These results showed that perturbations of sodium intake have major impacts on the structure and functions of the uterine arterial circulation, indicating RAAS involvement in uterine vascular remodeling and function during gestation.     

Effects of in vivo administration of epidermal growth factor (EGF) on uterine contractility, prostaglandin production and timing of parturition in rats

Prostaglandins synthesized by cyclooxygenases elicit uterine contractions during labour. Nitric oxide synthases (NOS) produce nitric oxide (NO), which maintains uterine quiescence during pregnancy. Epidermal growth factor (EGF) interacts with prostaglandins and NO in many biological systems. The aim of this work was to study the effect of the in vivo administration of EGF on uterine contractility, prostaglandin production and timing of parturition in rats. EGF was injected into the uterine lumen of pregnant rats on day 20, 21 or 22 of gestation. Intra-uterine administration of 500 ng EGF on day 21 of gestation delayed parturition for 18 h compared with control rats. Administration of EGF was able to: (i) reduce cyclooxygenase expression in the uterus (determined by western blot analysis) and production of prostaglandins by the uterus (evaluated by conversion of [(14)C]arachidonate to labelled prostaglandins); (ii) decrease prostaglandin concentrations in amniotic fluid (radioimmunoassay); (iii) increase NO production (evaluated by conversion of [(14)C]arginine into [(14)C]citrulline); (iv) increase serum progesterone concentrations to more than control concentrations (P<0.05; radioimmunoassay); and (v) reduce the amplitude of the uterine contractions. The overall effect was a delay in the onset of delivery. This in vivo effect raises the question of whether exogenous EGF plays a role in the initiation of parturition.     

Effect of the dietary exposure of rat to di(2-ethyl hexyl) phthalate on their metabolic efficiency

The nutritional impact of di(2-ethyl hexyl) phthalate (DEHP), specifically its energy efficiency and nitrogen utilization, was studied in the experimental rat. Groups of male Wistar rats were fed over 21 days with a standard diet alone or a standard diet supplemented with 2% (w/w) DEHP. Food intake, body weight and nitrogen compounds excretion were measured daily. The composition and energetic content of the carcass were determined in animals of both dietary groups after the feeding period, as well as in a separate group on day 0. The food and energy intakes were similar in both groups, however, the efficiencies of energy and nitrogen use were significantly reduced in the DEHP-fed rat. These alterations were reflected by a reduction of 31% on carcass energy retention and a decrease of 26% on cumulative nitrogen balance, without changes in the body composition. The increase of urinary nitrogen excretion, mainly as urea compound, is the major contributing factor to the lower nitrogen retention. These results indicate that DEHP decreases energy efficiency and nitrogen utilization, leading to a pronounced reduction in body weight gain. In addition, this study provides a possible conceptual framework that could explain the metabolic changes induced by DEHP and related compounds in experimental animals.     

Effect of prepartal hormone administration on feed intake and mineral metabolism of cows.

Subcutaneous administration of progesterone (.25 mg/kg body weight per day) to mature cows from 14 days before projected parturition until parturition increased feed intake over control cows. Incidence of milk fever and plasma calcium, phosphorus, magnesium, and hydroxyproline were not significantly different between treated and control cows. Subcutaneous administration of estradiol-17beta (.05 mg/kg body weight per day) or oral administration of melengestrol acetate (1 mg/day) from 7 days before projected parturition date until parturition decreased feed intake over control cows. Milk fever incidence and absorption of calcium, phosphorus, and magnesium were not significantly different between treatment groups. Plasma calcium was not significantly different between treatment groups during either the prepartum or postpartal periods but tended to be higher postpartum in cows treated with estrogen.     

Analysis of vitamin and mineral sufficiency in children using data of consumption with food and urinary excretion

It has been shown that vitamin C and B2, calcium and phosphorus daily intake strongly correlated with their urinary excretion in children 5-8 years old (Moscow) from the decreased bone mineral density risk group. Hour urinary calcium, phosphorus, creatinine excretion values for adequately supplied children has been determined. Vitamin and mineral status evaluation by means of estimation of vitamins and minerals consumption and urinary level (except vitamin B2) give relatively coincided results. Difference between these methods of nutritive status assessment attains 8-25 per cent. Thus these methods are substituted for group nutritive status evaluation.     

Enzymeimmunoassay of oestradiol,testosterone and progesterone in urine samples from female mice before and after insemination

ELISA measurements of 17beta-oestradiol, testosterone and progesterone were determined for urine samples collected non-invasively from female mice. Initial samples were collected during 5 successive days while mature female mice were isolated and cyclic. Subsequently, female mice were inseminated and additional urine samples were collected during days 2-6 after observation of copulatory plugs. Measurements of oestradiol and testosterone showed variance over days within individuals and did not significantly differ in measurements taken before or after insemination. Progesterone concentrations were significantly higher after insemination compared with before mating. In a second sample of inseminated females, urinary progesterone was measured during days 2-18 of pregnancy. Most females showed high urinary progesterone up to day 10 of pregnancy and lower concentrations during the remainder of gestation. These results indicate that urinary progesterone reflects established systemic increases of this hormone during pregnancy.     

Bioavailability of calcium,magnesium and phosphorus in rats fed probiotic,prebiotic and synbiotic powder follow‐up infant formulas and their effect on physiological and nutritional parameters

The effect of infant formulas supplemented with functional ingredients on calcium (Ca), magnesium (Mg) and phosphorus (P) bioavailability was investigated in rats. Seven follow‐up infant formulas containing probiotics (Bifidobacterium bifidum and Bifidobacterium longum), prebiotics (galactooligosaccharides at 12, 50 and 100 g kg^?1) or synbiotics (bifidobacteria and galactooligosacccharides) were administered to weanling rats for 30 days. A 3 day mineral balance was performed over three periods (8–10, 18–20 and 28–30 days) to monitor mineral apparent absorption and retention ratios and physiological and nutritional parameters. Feeding rats on infant formula‐based diets showed high feed efficiency (≥0.46). It was found that infant formulas supplemented with probiotics and/or prebiotics for 30 days increased Ca, Mg and P bioavailability in rats. Mineral apparent absorption and retention ratios were higher than 90% for Ca and P and 80% for Mg during the first balance period regardless of the infant formula used, but they decreased during the next two balance periods. Although it was not possible to select one infant formula as the best to improve mineral absorption, the 100 g kg^?1 prebiotic and 50 and 100 g kg^?1 synbiotic infant formulas were the most efficient at increasing Ca, Mg and P bioavailability compared with the control group. Copyright © 2006 Society of Chemical Industry     

The expression of transforming growth factor beta in pregnant rat myometrium is hormone and stretch dependent

From a quiescent state in early pregnancy to a highly contractile state in labor, the myometrium displays tremendous growth and remodeling. We hypothesize that the transforming growth factor beta (TGFbeta) system is involved in the differentiation of pregnant myometrium throughout gestation and labor. Furthermore, we propose that during pregnancy the mechanical and hormonal stimuli play a role in regulating myometrial TGFbetas. The expression of TGFbeta1-3 mRNAs and proteins was examined by real-time PCR, Western immunoblot, and localized with immunohistochemistry in the rat uterus throughout pregnancy and labor. Tgfbeta1-3 genes were expressed differentially in pregnant myometrium. Tgfbeta2 gene was not affected by pregnancy, whereas the Tgfbeta1 gene showed a threefold increase during the second half of gestation. In contrast, we observed a dramatic bimodal change in Tgfbeta3 gene expression throughout pregnancy. Tgfbeta3 mRNA levels first transiently increased at mid-gestation (11-fold on day 14) and later at term (45-fold at labor, day 23). Protein expression levels paralleled the changes in mRNA. Treatment of pregnant rats with the progesterone (P4) receptor antagonist RU486 induced premature labor on day 19 and increased Tgfbeta3 mRNA, whereas artificial maintenance of elevated P4 levels at late gestation (days 20-23) caused a significant decrease in the expression of Tgfbeta3 gene. In addition, Tgfbeta3 was up-regulated specifically in the gravid horn of unilaterally pregnant rats subjected to a passive biological stretch imposed by the growing fetuses, but not in the empty horn. Collectively, these data indicate that the TGFbeta family contributes in the regulation of myometrial activation at term integrating mechanical and endocrine signals for successful labor contraction.     

Screening and quantification of 18 glucocorticoid adulterants from herbal pharmaceuticals and health foods by HPLC and confirmed by LC-Q-TOF-MS/MS

A procedure for the screening and quantification of 18 glucocorticoids, i.e. hydrocortisone sodium succinate (HSS), prednisolone (PDL), prednisone (PDS), hydrocortisone (HCS), methylprednisolone (MPS), betamethasone (BTM), dexamethasone (DXM), triamcinolone acetonide (TA), prednisolone acetate (PLA), hydrocortisone acetate (HA), fludrocortisone acetate (FA), prednisone acetate (PA), cortisone acetate (CA), dexamethasone acetate (DA), hydrocortisone butyrate (HB), triamcinolone acetonide acetate (TAA), fluocinonide (FN) and halcinonide (HC) from herbal pharmaceuticals and health foods was established and fully validated. The samples were extracted by methanol and separated by HPLC. The retention times and ultraviolet spectra were used for the preliminary screening, and the suspected adulterants were then confirmed by liquid chromatography-quadrupole-time of flight mass spectrometry (LC-Q-TOF-MS/MS) and quantified by HPLC. The developed procedure was successfully applied to 14 herbal samples, and 316.3 µg g^–1 of DA and 13.6 µg mL^–1 of BTM were found in a tablet sample and a spray sample, respectively. To our best knowledge, this is the first report of the simultaneous screening and quantification of these 18 glucocorticoids from any matrix.