[show abstract][hide abstract] ABSTRACT: Phytoestrogens, naturally occurring plant compounds having oestrogenic and/or anti-oestrogenic activity, are present in many human foodstuffs including hop. Moderate intakes of isoflavonoid phytoestrogens have been associated with a reduction in cardiovascular diseases incidence. So, it is possible that hop (Humulus Lupulus L.) might similarly contribute to the reported health-beneficial effects of moderate beer consumption. Thus, the purpose of this study was to investigate in vitro effects of aqueous hop extract on thoracic vascular reactivity in Sprague Dawley male and female rats. Endothelium-intact thoracic arterial rings from male rats (MALE, n=8), sham-ovariectomized (Sham OVX) female (n=8) and ovariectomized (OVX) female rats (n=8) were used. We assessed the relaxation induced by aqueous hop extract (10(-9), 10(-2)g/l) in aortic rings precontracted with norepinephrine (10(-7)M), in the absence or in the presence of l-NAME (10(-4)M), indomethacin (10(-5)M), thapsigargin (10(-4)M), iberiotoxin (3.10(-8)M), apamin (3.10(-8)M) and TEA (3.10(-4)M). Aqueous hop extract induced relaxation of endothelium-intact thoracic arterial rings in MALE and Sham OVX rats, whereas a weak effect was observed in OVX rats. This vasorelaxation was strongly inhibited in presence of l-NAME, indomethacin and thapsigargin. These data indicated that aqueous hop extract-induced vasodilation, in male and intact female rats, is mediated by NOS activation, cyclooxygenase products and Ca(2+) pathways. Moreover, our results suggested that effect of hop in enhancing vascular reactivity was independent of gender but strongly related to hormonal status.
Phytomedicine: international journal of phytotherapy and phytopharmacology 04/2008; 15(3):185-93. · 2.17 Impact Factor
[show abstract][hide abstract] ABSTRACT: We investigated in female rats the effects on bone metabolism of a prolonged no-training period, subsequent to an isometric exercise program, performed during young adulthood and those of a long-term consumption of Humulus lupulus L-enriched diet (genistein 1.92 and daidzein 1.24 mg/kg diet) combined or not with isometric training. Forty-eight rats (4 weeks old) were randomly divided into 4 groups: trained (C-Tr) or nontrained rats (C-NTr) fed with control diet and trained (H-Tr) or nontrained rats (H-NTr) fed with Humulus lupulus L-enriched diet. The diets lasted 100 weeks. Training was followed over a 25-week period. Bone parameters were measured at week 100. Our results showed that no significant difference was observed among the 4 groups in uterine relative weight, calcium (Ca) intake, fecal Ca, urinary Ca excretion, net Ca absorption, plasma Ca, and bone Ca content. Calcium balance was significantly enhanced in H-NTr rats in comparison with C-NTr and C-Tr rats. Isometric strength training led to a significant increase in total bone mineral density (BMD), diaphyseal BMD, and osteocalcin-deoxypyridinoline ratio in C-Tr rats compared with the other groups. The main findings of the present study indicate that in female rats, a 25-week isometric strength training performed during young adulthood followed by a prolonged no-training period increases BMD values and osteocalcin-deoxypyridinoline ratio, whereas long-term consumption of Humulus lupulus L-enriched diet does not improve bone parameters. It suggests that bone gains induced by exercise do not decrease immediately after cessation of training and also confirms the importance of the practice of physical activity during puberty and young adulthood to maximize the achieved peak bone density.
[show abstract][hide abstract] ABSTRACT: Using female 4-week-old Sprague-Dawley rats, we investigated the effects of 14 weeks of progressive strength isometric training on endothelium dysfunction after estrogen deficiency. We also proposed possible mechanism(s) by which such training acted on endothelium-dependent vasodilation in thoracic aortic rings. Rats were randomly divided into 4 groups of 8 rats: a sham operated group, an ovariectomized sedentary group receiving 17beta-estradiol vehicle s.c. daily, an ovariectomized sedentary group receiving a daily injection of 20 microg.kg(-1) 17beta-estradiol s.c., and an ovariectomized exercised group receiving daily s.c. vehicle. Vascular reactivity of aortic rings have been evaluated by a cumulative dose of acetylcholine (ACh), in the presence or absence of L-NAME (N-nitro-L-arginine methyl ester), indomethacin, thapsigargin, iberiotoxin, apamin, and tetraethylammonium. Ovariectomy markedly decreased the relaxation caused by ACh, whereas 17beta-estradiol treatment induced a significant increase in the relaxation elicited by ACh. Isometric exercise enhanced relaxation due to ACh. This enhancement was attenuated in the presence of L-NAME, indomethacin, thapsigargin, iberiotoxin, and apamin. Our data indicated, for the first time, that the endothelium-dependent relaxant response to ACh was markedly improved in trained ovariectomized rats. This increased vasodilation is mediated by nitric oxide, cyclooxygenase, sarco-endoplasmic reticulum Ca2+-ATPase pathways, and endothelium-derived hyperpolarizing factor. Finally, this study suggested that resistance training may provide benefits in addressing vascular dysfunction consequent to a decline in estrogen levels after menopause. However, any benefits for age-related vascular dysfunction remain to be demonstrated.
[show abstract][hide abstract] ABSTRACT: Soybean proteins, a rich source of isoflavones, taken immediately after an ovariectomy prevent bone loss in rats. Exercise-induced stimuli are essential for bone growth. Few studies exist about the combined effects of swim training and soybean protein supplementation on bone metabolism. So, the purpose of this study was to investigate, in 48 female Sprague-Dawley rats (12 weeks old) the effects of an 8-week swim-training regimen (1 h/day, 5 days/week) and dietary soybean proteins (200 g/kg diet) on bone metabolism. Rats were randomly assigned to four groups: (1) ovariectomized fed with a semisynthetic control diet; (2) ovariectomized fed with a soybean protein-enriched semisynthetic diet; (3) ovariectomized trained to exercise and fed with control diet; (4) ovariectomized trained to exercise and fed with a soybean protein diet. Following the treatment period, body weight gain was identical in the four groups. Soybean protein supplementation increased bone calcium content, and reduced plasma osteocalcin values, without significant modification of calcium balance and net calcium absorption. Swim training enhanced plasma and bone calcium content and calcium balance and net calcium absorption. It did not modify either plasma osteocalcin values or urinary deoxypyridinoline excretion. Both exercise and soybean protein intake increased plasma on bone calcium without modifying net calcium absorption or bone markers. In conclusion, we demonstrated, in ovariectomized rats, that swimming exercise and dietary supplementation with soy proteins do not have synergistic effects on calcium metabolism and bone markers.
Journal of Bone and Mineral Metabolism 02/2006; 24(3):206-12. · 2.22 Impact Factor
[show abstract][hide abstract] ABSTRACT: IntroductionOvariectomy in animals reduces endothelium-dependent relaxation. On the other hand, endurance training improves the endothelial function. The purpose of this in vivo study was to investigate, in female Sprague–Dawley rats, the effects of a 14-week progressive strength isometric training on endothelium dysfunction induced by estrogen deficiency.
[show abstract][hide abstract] ABSTRACT: The purpose of this study was to investigate the effects of a 8-week of swim training on total plasma homocysteine and cysteine levels in 16 male Sprague-Dawley rats aged 17 weeks. We also evaluated the activity of hepatic cystathionine beta-synthase (CBS), an enzyme involved in the metabolism of Hcy, the concentration of plasma glutathione, taurine, and a fraction of vitamin B6: the pyridoxal 5-phosphate (PLP). After one week of acclimatization, rats were randomly divided into two groups: 8 non-trained (NTR) and 8 trained rats (TR). Following the training period, body weight gain was lower in TR than in NTR. Plasma homocysteine did not differ among groups while significantly lower plasma cysteine and taurine levels were found in TR (157.83 +/- 8.6 micromol/L; 133.01 +/- 9.32 micromol/L; P < 0.05) compared with data of NTR (176.19 +/- 4.9 micromol/L; 162.57 +/- 8.16 micromol/L; P < 0.05). No significant changes in hepatic CBS activity were observed in TR compared with NTR. Moreover, values for plasma glutathione and PLP concentrations were not affected by training.These results indicate that training reduces plasma cysteine and taurine levels whereas it does not modify other studied parameters. Thus, physical training may regulate cysteine metabolism.
[show abstract][hide abstract] ABSTRACT: The aim of this study was to evaluate whether endurance exercise in middle-aged men induces changes in plasma total homocysteine (tHcy) and total cysteine (tCys), and whether these changes depend on the diet especially on vitamin B(6), folic acid and vitamin B(12) intakes.
Twelve trained subjects (52.33 +/- 2.4 years) and twelve untrained subjects (56.23 +/- 0.9 years) volunteered for the present study. tHcy and tCys were measured with high-pressure liquid chromatography at rest in both groups and during an incremental exercise performed on a cycle ergometer until exhaustion in the trained subjects.
At baseline homocysteinemia and cysteinemia were lower in trained subjects (7.48 +/- 0.4 and 183.45 +/- 13.6 micromol/l) compared with untrained subjects (9.79 +/- 0.4 micromol/l, p < 0.001; 229.01 +/-14.7 micromol/l, p < 0.05, respectively). Incremental exercise also induced a decrease in tHcy and tCys concentrations. Moreover, tHcy concentration was negatively related to the folic acid and B(12) intakes in untrained (r = -0.589, p < 0.05; r = -0.580, p < 0.05, respectively) as well as in trained groups (r = -0.709, p < 0.01; r = -0.731, p < 0.01, respectively) whereas no correlation between tCys and vitamin in the diet was observed.
This study demonstrates that the combined effects of a chronic physical exercise and a high folate and vitamin B(12) intake could be responsible for the reduction of plasma tHcy and tCys concentrations that might be a key for the prevention of many diseases.
Annals of Nutrition and Metabolism 01/2005; 49(2):125-31. · 1.66 Impact Factor