Effects of green tea or Sasa quelpaertensis bamboo leaves on plasma and liver lipids, erythrocyte Na efflux, and platelet aggregation in ovariectomized rats.

This study was conducted to investigate the effects of Sasa quelpaertensis bamboo and green tea on plasma and liver lipids, platelet aggregation, and erythrocyte membrane Na channels in ovariectomized (OVX) rats. Thirty female rats were OVX, and ten female rats were sham-operated at the age of 6 weeks. The rats were divided into four groups at the age of 10 weeks and fed the experiment diets: sham-control, OVX-control, OVX-bamboo leaves (10%), or OVX-green tea leaves (10%) for four weeks. Final body weight increased significantly in the OVX groups compared with that in the sham-control, whereas body weight in the OVX-green tea group decreased significantly compared with that in the OVX-control (P < 0.01). High density lipoprotein (HDL)-cholesterol level decreased in all OVX groups compared with that in the sham-control rats (P < 0.05) but without a difference in plasma total cholesterol. Plasma triglycerides in the OVX-green tea group were significantly lower than those in the sham-control or OVX-control group (P < 0.05). Liver triglycerides increased significantly in the OVX-control compared with those in the sham-control (P < 0.01) but decreased significantly in the OVX-green tea group compared with those in the OVX-control or OVX-bamboo group (P < 0.01). Platelet aggregation in both maximum and initial slope tended to be lower in all OVX rats compared with that in the sham-control rats but was not significantly different. Na-K ATPase tended to increase and Na-K cotransport tended to decrease following ovariectomy. Na-K ATPase decreased significantly in the OVX-green tea group compared with that in the OVX-control group (P < 0.01), and Na-K cotransport increased significantly in the OVX-bamboo and OVX-green tea groups compared with that in the OVX-control (P < 0.05). Femoral bone mineral density tended to be lower in OVX rats than that in the sham-control, whereas the green tea and bamboo leaves groups recovered bone density to some extent. The results show that ovariectomy caused an increase in body weight and liver triglycerides, and that green tea was effective for lowering body weight and triglycerides in OVX rats. Ovariectomy induced an increase in Na efflux via Na-K ATPase and a decrease in Na efflux via Na-K cotransport. Furthermore, consumption of green tea and bamboo leaves affected Na efflux channels, controlling electrolyte and body water balance.

Effects of gender and gonadectomy on growth and plasma cholesterol levels in pigs.

We conducted two studies to determine the effect of gender, gonadectomy (GDX) on growth and plasma cholesterol levels in pigs. In experiment 1, five sham-operated and five GDX female Landrace pigs (26 kg) were allowed to have free access to water and feed up to market weight (approximately 100 kg). Body weight and feed consumption were recorded biweekly, and daily body weight gain, daily feed intake and feed efficiency (gain/feed) were calculated during the feeding period. In experiment 2, 10 male (26 kg) and 10 female (26 kg) Landrace pigs were used; five male and five female pigs were assigned to sham-operated or GDX. Pigs were allowed to have free access to water and a diet without added cholesterol (Table 1) until they were 6 months old (male 104 and female 98 kg) and thereafter they were fed a hypercholesterolemic diet (Table 1) containing 0.5% cholesterol and 0.1% cholate for 10 days. GDX of female pigs increased average daily gain (P<0.05), compared with their sham-operated counterparts during the growing-finishing period, but had no effect (P>0.05) on feed efficiency. Plasma cholesterol levels in pigs fed a hypercholesterolemic diet for 10 days were much higher (P<0.05) in females than in males (161 vs 104 mg/100 mL plasma), and were increased by GDX only in male pigs. HDL-cholesterol/LDL+VLDL-cholesterol ratio appeared to be higher in males than in females, and was not influenced by GDX in either sex. Results suggested that the lower growth rate of female pigs than their male counterparts is attributable to the ovarian activity, and the lower plasma cholesterol level in male than in female pigs fed a hypercholesterolemic diet is due to the testicular activity.

Effects of gender, gonadectomy and sex hormones on growth and plasma cholesterol level in rats.

BACKGROUND/AIMS: No studies have clearly demonstrated how sex hormones are involved in the observed gender difference in growth and plasma cholesterol levels in animals fed hypercholesterolemic diets. This study was conducted to determine the effects of gender, gonadectomy (GNX), and sex hormones on growth, plasma cholesterol and cortisol levels in Sprague-Dawley rats. METHODS: In the first of two experiments, equal numbers of male and female 4-week-old rats were divided into three groups: sham-operated control, GNX, or GNX + 17alpha-methyltestosterone (MT). The rats were fed a hypercholesterolemic diet for 4 weeks. In a second experiment, 24 GNX females were equally divided into three groups: control, 17beta-estradiol (E(2)), or MT. These rats were fed a normocholesterolemic diet for 3 weeks. RESULTS: The average total plasma cholesterol level in female rats was twice that in male rats. MT administration to GNX male and GNX female rats decreased plasma cholesterol levels by 23 and 45%, respectively. Weekly intramuscular injection of E(2) markedly suppressed growth while increasing plasma cortisol levels in GNX female rats. CONCLUSION: Testosterone decreases plasma cholesterol levels in rats fed a hypercholesterolemic diet and E(2) suppresses growth of rats, inducing the secretion of hormones that increase with stress.

Effects of very-low-carbohydrate (horsemeat- or beef-based) diets and restricted feeding on weight gain, feed and energy efficiency, as well as serum levels of cholesterol, triacylglycerol, glucose, insulin and ketone bodies in adult rats.

BACKGROUND/AIMS: The beneficial or harmful effect of the low-carbohydrate (low-carb), high-protein, high-fat diet (Atkins diet) has not been clearly demonstrated. We determined the effect of a low-carb diet and restricted feeding (70% ad libitum intake) on serum levels of cholesterol, triacylglycerol, glucose, ketone bodies and insulin in rats. METHODS: In experiment 1, each of 4 groups with 10 adult rats was assigned to a high-carb diet (AIN-93G) + ad libitum intake or restricted feeding, or a low-carb diet (53% horsemeat) + ad libitum intake or restricted feeding (2 x 2 factorial). In experiment 2, each of 3 groups with 10 adult rats was assigned to a control (AIN-93G) or low-carb diets (53% beef or horsemeat). RESULTS: Restricted feeding and the low-carb diet reduced (p<0.01) serum triacylglycerol compared with ad libitum intake and the AIN-93G diet, respectively (experiment 1). The dietary effect on serum total cholesterol, high-density or low-density lipid cholesterol appeared to be inconsistent, but restricted feeding increased the low-density lipoprotein cholesterol level. The serum ketone body level was increased by the low-carb diet compared with AIN-93G (experiment 2). CONCLUSION: Restricted feeding and a low-carb diet are beneficial for alleviating cardiovascular disease risk factors, and their effects are additive, restricted feeding being more pronounced.

Nutritional characteristics of horsemeat in comparison with those of beef and pork.

This study was conducted to determine the nutritional characteristics of horsemeat and bone meal in comparison with those of beef and pork presented by Dietary Reference Intakes For Koreans. Longissimus muscle and large metacarpal bone samples were collected from 20 fattened Jeju horses. Muscle samples were subjected to proximate analysis, assays for fatty acid profile and minerals, and bone samples to mineral assays. Horsemeat had similar levels of protein (21.1 vs 21.0 or 21.1%) and lower levels of fat (6.0 vs 14.1 or 16.1%) compared with beef or pork, respectively. Horsemeat had much higher levels of palmitoleic (8.2 vs 4.4 or 3.3%) and alpha-linolenic (1.4 vs 0.1 or 0.6%) acids than beef or pork, respectively. Linoleic acid was much higher in horsemeat (11.1%) and pork (10.1%) than in beef (1.6%). PUFA:SFA and n-6:n-3 ratios in horsemeat were 0.29 and 10.2, respectively. There were no big differences in mineral contents between horsemeat, beef and pork. For daily recommended mineral intakes of male adults (Dietary Reference Intakes For Koreans), phosphorus, sodium, potassium, iron, zinc and copper can be provided up to 24, 2.5, 6.7, 21, 26 and 40%, respectively, by 100 g raw horsemeat, but calcium and manganese levels are negligible. Horse cannon bone had much higher mineral contents especially in calcium (10,193 mg/100 g), phosphorus (5,874 mg/100 g) and copper (0.79 mg/100 g). Thiamin, riboflavin, niacin and retinol contents were 0.20, 0.21, 1.65 mg/100 g and 30 microg/100 g, respectively. But ascorbic acid and beta-carotene were not detected. Our data demonstrated that higher levels of palmitoleic and alpha-linolenic acid in horsemeat than in beef and pork may be beneficial for human health. Horsemeat and bone meal are a good source of some minerals and vitamins.

Detection of abnormally high amygdalin content in food by an enzyme immunoassay.

Amygdalin is a cyanogenic glycoside compound which is commonly found in the pits of many fruits and raw nuts. Although amygdalin itself is not toxic, it can release cyanide (CN) after hydrolysis when the pits and nuts are crushed, moistened and incubated, possibly within the gastrointestinal tract. CN reversibly inhibits cellular oxidizing enzymes and cyanide poisoning generates a range of clinical symptoms. As some pits and nuts may contain unusually high levels of amygdalin such that there is a sufficient amount to induce critical CN poisoning in humans, the detection of abnormal content of amygdalin in those pits and nuts can be a life-saving measure. Although there are various methods to detect amygdalin in food extracts, an enzyme immunoassay has not been developed for this purpose. In this study we immunized New Zealand White rabbits with an amygdalin-KLH (keyhole limpet hemocyanin) conjugate and succeeded in raising anti-sera reactive to amygdalin, proving that amygdalin can behave as a hapten in rabbits. Using this polyclonal antibody, we developed a competition enzyme immunoassay for determination of amygdalin concentration in aqueous solutions. This technique was able to effectively detect abnormally high amygdalin content in various seeds and nuts. In conclusion, we proved that enzyme immunoassay can be used to determine the amount of amygdalin in food extracts, which will allow automated analysis with high throughput.

Phylogenetic relationships of Northeast Asian cattle to other cattle populations determined using mitochondrial DNA D-loop sequence polymorphism.

Phylogenetic relationships of Northeast Asian cattle to various other cattle breeds including Bos taurus, Bos indicus, and Bison bison were assessed using mtDNA D-loop sequences. A neighbor-joining tree was constructed using sequences determined for 4 Cheju Black, 4 Cheju Yellow, 4 Korean Yellow cattle (Bos taurus), and 2 American Brahman cattle (Bos indicus), and also published sequences for 31 Japanese Black cattle, 45 European breed cattle, 6 African zebus, 2 African taurines, and 6 Indian zebus. Five American bisons (Bison bison) were used as an outgroup. The neighbor-joining tree showed that American bisons and Indian zebus are clearly separate from other cattle breeds, respectively, and African cattle clustered together, although with a low bootstrap probability (< 50%). Results indicate that cattle in Northeast Asia, Europe, and Africa are closely related to each other-suggesting their recent divergence, but are separate from Indian zebus.

Differential incorporation of biotinylated polyamines by transglutaminase 2.

Polyamine incorporation or cross-linking of proteins, post-translational modifications mediated by transglutaminase 2 (TGase 2), have been implicated in a variety of physiological functions including cell adhesion, extracellular matrix formation and apoptosis. To better understand the intracellular regulation mechanism of TGase 2, the properties of biotinylated polyamines as substrates for determining in situ TGase activity were analyzed. We synthesized biotinylated spermine (BS), and compared the in vitro and in situ incorporation of BS with that of biotinylated pentylamine (BP), which is an artificial polyamine derivative. When measured in vitro, BP showed a significantly higher incorporation rate than BS. In contrast, in situ incorporation of both BS and BP was not detected even in TGase 2-overexpressed 293 cells. Cells exposed to high calcium showed a marked increase of BP incorporation but not of BS. These data indicate that the in situ activity of TGase 2 gives different results with different substrates, and suggest the possibility of overrepresentation of in situ TGase 2 activity when assayed with BP. Therefore, careful interpretation or evaluation of in situ TGase 2 activity may be required.