In conclusion, long-term equol consumption, like genistein and daidzein, in the ovariectomized rat, provides bone sparing effects. Adding indigestible sugars, such as FOS or live microbial as L. casei, in the diet significantly improves daidzein protective effects on the skeleton.

Hesperidin (Hp), a citrus flavonoid predominantly found in oranges, shows bone-sparing effects in ovariectomised (OVX) animals. In human subjects, the bioavailability of Hp can be improved by the removal of the rhamnose group to yield hesperetin-7-glucoside (H-7-glc). The aim of the present work was to test whether H-7-glc was more bioavailable and therefore more effective than Hp in the prevention of bone loss in the OVX rat. Adult 6-month-old female Wistar rats were sham operated or OVX, then pair fed for 90 d a casein-based diet supplemented or not with freeze-dried orange juice enriched with Hp or H-7-glc at two dose equivalents of the hesperetin aglycone (0·25 and 0·5 %). In the rats fed 0·5 %, a reduction in OVX-induced bone loss was observed regarding total bone mineral density (BMD): þ 7·0 % in OVX rats treated with Hp (HpOVX) and þ 6·6 % in OVX rats treated with H-7-glc (H-7-glcOVX) v. OVX controls (P,0·05). In the rats fed 0·25 % hesperetin equivalents, the H-7-glcOVX group showed a 6·6 % improvement in total femoral BMD v. the OVX controls (P,0·05), whereas the Hp diet had no effect at this dose. The BMD of rats fed 0·25 % H-7-glc was equal to that of those given 0·5 % Hp, but was not further increased at 0·5 % H-7-glc. Plasma hesperetin levels and relative urinary excretion were significantly enhanced in the H-7-glc v. Hp groups, and the metabolite profile showed the absence of eriodictyol metabolites and increased levels of hesperetin sulphates. Taken together, improved bioavailability of H-7-glc may explain the more efficient bone protection of this compound.Bioavailability: Bone mineral density: Hesperidin: Flavanones: Rats Nutrition plays an important role in the dietary management and prevention of osteoporosis, a major public health problem. While it is established that Ca, vitamin D and micronutrients are essential for bone health, other compounds such as polyphenols, found abundantly in fruit and vegetables, show potential for bone-protective effects. For example, rodent studies have shown that quercetin and quercetin-3-rhamnoglucoside (rutin) from onions (1,2) , resveratrol from red wine (3) and isoflavones from soya (4) inhibit ovariectomised (OVX)-induced bone loss. Until now, most of the human intervention studies have been carried out with high levels of soya isoflavones (80-90 mg), some studies showing prevention of bone loss in postmenopausal women (5,6) , while others not (7,8) . The level of consumption of soya products is rather low in Western countries compared with Asian ones, whose daily intakes average 20 -40 mg (9) . Therefore, it would be of interest to identify commonly consumed polyphenols with bone-protective effects, as soya is not used as a staple in the Western diet.Hesperidin (Hp), a monomethoxylated flavanone found abundantly in citrus fruits such as oranges (10) , is highly consumed in Western countries. Indeed, in Finland, Hp consumption was estimated to be 28 mg/d, contributing to 50 % of total flavonoid intake (11) . Hp and metabolites show promising health benefit...

Chronic exposure to isoflavones in postmenopausal women resulted in plasma concentrations as high as 2.5-5 micromol/l of each isoflavone, but did not induce the ability to produce equol.

Isoflavones (IF) have been increasingly implicated for use in the prevention of osteoporosis. As their bioavailability could be improved by modulating intestinal microflora, the present study was undertaken to investigate whether IF and fructooligosaccharides (FOS), which are known to modify large-bowel flora and metabolism, may exhibit a cooperative bone-sparing effect. This work was carried out on 3-month-old Wistar rats assigned to 12 groups: 2 SH (sham-operated) and 10 OVX (ovariectomized). Animals received a diet for 90 days containing total IF (Prevastei HC, Central Soya) at 0 (OVX and SH), 10 (IF10), 20 (IF20), 40 (IF40), or 80 (IF80) microg/g body weight per day. FOS (Actilight, Beghin-Meiji) were orally given to half of the groups, (OVX FOS), (IF10 FOS), (IF20 FOS), (IF40 FOS), (IF80 FOS), and (SH FOS). Isoflavones exhibited a bone-sparing effect as soon as consumption reached 20 microg/g/day, whereas only the highest dose induced a weak uterotrophic activity. Indeed, total femoral bone mineral density (BMD) was significantly enhanced (compared with that of OVX rats), as was the metaphyseal compartment. Bone strength was improved as well. As far as the FOS diet is concerned, addition of prebiotics significantly raised the efficiency of the IF protective effect on both femoral BMD and mechanical properties. The trend toward higher BMD levels with the lowest IF dose (IF10) even reached a significant level when FOS were added. This effect could be explained by a reduced bone resorption. In conclusion, daily IF consumption prevented castration-induced osteopenia by decreasing bone resorption when given at 20, 40, or 80 microg (total isoflavones)/g/day. Simultaneous FOS consumption improved IF protective effect on the skeleton, with the lowest IF dose becoming efficient. Enhancement of IF bioavailability, following FOS fermentation, is probably involved.

Abstract. Ovine corticotrophin-releasing factor (oCRF) (1 μg/kg) and arginine vasopressin (AVP) (1 μg/kg) were injected iv in sheep, both separately and in combination. Plasma levels of immunoreactive ACTH (IRACTH), cortisol, and aldosterone were measured for 3 h after the injections. Mean levels before injections were 8 ± 4 pmol/l for ACTH, 7 ± 3 nmol/l for cortisol, and 28 ± 9 pmol/l for aldosterone. CRF caused a rapid rise in IR-ACTH and a peak level of 125 ± 52 pmol/l was obtained 15 min after injection. Highest values for cortisol and aldosterone levels were 40 ± 9 nmol/l and 64 ± 13 pmol/l, respectively, 30 min after injection. AVP also increased IR-ACTH (maximum level: 202 ± 77 pmol/l at 5 min) and aldosterone (128 ± 36 pmol/l at 15 min), whereas the cortisol increase was lower than after CRF. Simultaneous injection of CRF and AVP produced an addition of the IR-ACTH response (295 ± 82 pmol/l at 15 min), but the changes in cortisol levels were similar to those obtained after CRF alone and those in aldosterone levels resembled those induced by AVP alone. Plasma Na and K, osmolality, and plasma renin activity (PRA) were not modified by either CRF or AVP. It is suggested that the increase in aldosterone levels after CRF could be mediated by ACTH and that after AVP by an IR-ACTH peptide with less effect on cortisol secretion.

This paper reports that the selective beta(2)-adrenergic receptor agonist clenbuterol affects bone metabolism in growing 3-mo-old male Wistar rats treated over 8 wk. Thirty-two 3-mo-old growing Wistar rats weighing 234 +/- 2 g were assigned to a progressive isometric force, strength-training exercise program plus oral clenbuterol (2 mg x kg body wt(-1) x day(-1)) for 5 days each week, exercise program without clenbuterol 5 days each week, no exercise program plus oral clenbuterol (2 mg x kg(-1) x day(-1)) for 5 days each week, or no exercise without clenbuterol 5 days each week. At the end of 8 wk, lean mass, fat mass, and right total femoral, distal metaphyseal femoral, and diaphyseal femoral bone mineral density were measured by Hologic QDR 4,500 dual X-ray absorptiometry (DEXA) technique. Left femoral bones were harvested after death on day 58, and femoral resistance was determined by three-point bending testing. We found that fat mass was decreased in rats given strength training exercise and decreased further in rats treated with clenbuterol. Lean mass was increased in clenbuterol-treated animals. Strength-training exercise appeared to have no effect on bone mineral density, serum osteocalcin, or urinary deoxypyridinoline. However, clenbuterol treatment decreased femoral length, diameter, bone mineral density, and mechanical resistance. Clenbuterol had no effect on osteocalcin but increased urinary deoxypyridinoline. We concluded that clenbuterol treatment decreased bone mineral density and increased bone resorption independent of the level of exercise rats were given.

Summary. Seven groups of 10 growing rats each were fed a control diet or rapeseed diets with glucosinolate contents ranging from 4.4 to 36.6 mM/kg DM. After a 5-day adaptation period, the rats were fed ad libitum for 17 days.The food intake of the experimental groups was maximal after 11 days and was, on an average, 4 to 45 % lower than that of the control group. The differences were still greater during the last 7 days. Daily weight gain was also maximal after 8 days and began to decrease, dropping to 1 g during the last days. There were negative curvilinear relationships between food intake or weight gain and diet glucosinolate content. Liver weight (g/100 g of body weight) was not significantly altered by glucosinolate intakes between 0.08 and 0.39 mM/day. However, in the groups fed the diets with the lowest glucosinolate contents, plasma triiodothyronine (T 3 ) and thyroxine (T 4 ) levels were 50 % lower than in the control group and 70 or 80 % lower, respectively, with the diets having the highest glucosinolate contents.Introduction.

Study was carried out an Wistar female rats to evaluate the consequences of ovariectomy and 17 beta-estradiol substitutive treatment during aging on bone. Ca metabolism and calciotropic hormones. Three groups of fifteen rats, mature, old and senescent (4-, 10-, and 28 month-old) female were fed a diet (6 g/100 g BW/day) containing 0.9% Ca and 0.8% Pi, Within each group, 10 rats were surgically ovariectomized (OVX). From day 1 until day 60 after OVX, they were subcutaneously injected with either 17 beta-estradiol (E: 10 micrograms/kg BW/48 h; n = 5) or with solvent alone (OVX; n = 5). Five other rats were sham operated (SH) and received solvent alone. Animals were put in balance 1 day per week to determine Ca and Pi intestinal apparent absorption and urinary pyridinium cross-links excretion was measured by HPLC. All rats were killed by exsanguination 60 days after OVX. Plasma was collected for measurement of intact parathyroid hormone (PTH), calcitonin (CT), insulin-like growth factor-1 (IGF-1), Ca and Pi. The success of OVX was confirmed at necropsy by observation of marked atrophy of the uterine horns. The right femur was collected, cleaned from adjacent tissue and used for mineral analysis. Despite correct matching for feeding, BW was significantly larger in 6 and 12 month-old OVX rats. OVX and 17 beta-estradiol had no significant effect upon plasma Ca, Pi and CT concentrations. Aging is associated with increased circulating PTH levels (pg/ml) (SH-6 months: 50.8 +/- 12.6; 12 months: 219.1 +/- 34.9; 30 months: 158.7 +/- 23.5; P < 0.05). Urinary and fecal Ca and Pi excretion in senescent animals were higher than in adult or old rats, thus resulting in a drastic fall in both intestinal apparent absorption and retention of Ca and Pi in 30 month-old animals. In each group, urinary pyridinium cross-links excretion and plasma osteocalcin concentration were higher in the OVX animals than in the controls, consistent with increased bone turnover in the estrogen deficient state. Both biochemical turnover markers were reduced in the estrogen-treated groups. In the same way, OVX increased and estrogen decreased the plasma IGF-1 levels. We conclude that 17 beta-estradiol prevents high turnover-induced osteopenia even in 30 month-old rats.