The relative effect of dietary fats and carbohydrates on lipid metabolism in the albino rat

This study is concerned with the effect of two carbohydrates, cane-sugar and corn starch, at four different levels in the presence of two dietary fats, on the serum and the tissue lipids (cholesterol, phospholipid and fatty acid patterns). Keeping the dietary fats (coconut safflower seed oil) at 20% level, diets containing (a) startch (54%) + cane sugar (0%), (b) starch (44%) + cane sugar 10%), (c) starch (10%) + cane sugar (44%) and (d) only cane sugar (54%) were administered to rats for 8 weeks. The lipid levels were determined at the end of the feeding period. The beneficial effect of the unsaturated fat in lowering the serum cholesterol level is nullified by an excess of cane sugar in the diet. In liver, there is an increase of 40-50% of cholesterol, as the cane sugar level in the diet is raised, irrespective of the type of dietary fat. The fatty acid pattern of the serum and tissue lipids is influenced by dietary fats as well as carbohydrates.     

The effect of a subnormal dose of vitamin B6 on plasma lipid in the rat

In order to understand the mechanisms by which capsaicin at high concentrations affects the micturition reflex and detrusor contractility, in vivo and in vitro whole bladder studies were conducted using ganglionic blockers and a neurokinin receptor antagonist. Thirty-eight adult rats were divided into control (normal saline cystometry) and experimental (1,000 microM capsaicin cystometry) groups. Both groups were subdivided to receive pretreatment with intravesical hexamethonium, perivesical hexamethonium, or intravesical spantide ([D-Arg1, D-Trp7,9, Leu11]-substance P). After in vivo cystometry, the bladders were removed and in vitro whole bladder contractility studies using electrical field stimulation as well as bethanechol and KCl stimulations were performed. In the bladders pretreated with perivesical hexamethonium, the amplitudes of contractions and in vitro detrusor contractility under electrical stimulation were decreased. Other bladder preparations showed no significant differences from the controls. However, when 1,000 microM capsaicin was infused into the bladders, both control and experimental bladders showed an initial excitation and a final inhibition with an elevated basal intravesical pressure and retention. Capsaicin at 100 microM did not have this effect. The results of this study conclude that blockage of perivesical ganglia or neurokinin receptors in the submucosa did not influence the depressant effects of 1,000 microM capsaicin on the micturition reflex and detrusor contractility in rats. Nonspecific toxic effects on detrusor muscle or nerves is likely when intravesical high-concentration capsaicin is administered.     

Inhibitory effect of Garcinia kola on lipid peroxidation in rat liver homogenate

Garcinia kola, (a herb grown in Nigeria; calorific value 358.54 k.cal/100 g) inhibited in vitro lipid peroxidation of rat liver homogenate in a dose dependent manner. The inhibitory activity of G.kola was not affected by heating (100 degrees C/10 min). The antioxidant component of G.kola was soluble in aqueous and ethanolic media. The active component(s) in G. kola responsible for its inhibitory activity on lipid peroxidation is tentatively identified as isoflavones.     

The effect of anti-prolactin antibody on in vitro synthesis of a pregnancy-associated rat uterine glycoprotein

Experiments were conducted to study the hormonal (estrogen [E2], progesterone [P4] and prolactin [PRL]), regulation of synthesis of a pregnancy-associated glycoprotein (named Uterine Agglutinin or UA) in the Day 4 post coital (p.c.) rat uterus with antibody administration and immunohistochemistry. Of the antibodies used, it was shown that anti-PRL antibody was the most effective in reducing in vitro UA synthesis. The results suggested that in vitro UA synthesis could be correlated to serum PRL levels as analyzed by radio-immunoassay. Binding studies revealed that PRL bound specifically to the stromal cells of the rat uterus where UA is produced and localized.     

Antioxidant effect of cupric complex on NADPH-dependent lipid peroxidation in rat liver microsomes

The antioxidant effect of His-Cu (Histidine and cupric ion) on NADPH-dependent lipid peroxidation was proportional to the inhibitory effect on cytochrome c reduction i the presence of microsomes and ADP-Fe (ADP and ferric ion). The inhibiton of cytochrome c reduction by His-Cu caused no inhibition of NADPH oxidation. ADP-Fe stimulated NADPH oxidation in the absence of cytochrome c, and inhibited cytochrome c reduction. His-Cu inhibited NADPH-oxidation stimulated by ADP-Fe, but the antioxidant effect of His-Cu was independent of the effect on cytochrome b5 reduction. These results suggest that the antioxidant effect of His-Cu depends on the inhibitory effect on the electron transport from NADPH-cytochrome c reductase to ADP-Fe, but not on the inhibitory effect on the activity of the reductase.     

Stimulating effect of xanthene dyes on immunoglobulin produced in vitro by rat spleen lymphocytes

The effects of food additives on immunoglobulin produced in rat splenic lymphocytes were examined. The xanthene dye, Rose Bengal, enhanced IgE production, while inhibiting the production of IgG and IgM, at 50 microM. Among the xanthene dyes, Rose Bengal having 4 iodine and 4 chlorine atoms exerted the highest Ig production-regulating activity in splenocytes, and dihalogenated fluorescein, a diiodo compound, exerted similar activity, while the dichloro and dibromo compounds did not. These results suggest that halogen atoms, especially the iodine atom, in xanthene dyes play an important role in regulation of Ig production.     

Protective effect of dehydroepiandrosterone against copper-induced lipid peroxidation in the rat

This study investigates the effectiveness and multitargeted activity of dehydroepiandrosterone (DHEA) as antioxidant in vivo. A single dose of DHEA was given IP to male rats. Liver and brain microsomes, and plasma low density lipoprotein (LDL), were isolated from rats sacrificed 17 h later. Liver and brain microsomes were challenged with CuSO(4) and, as index of lipid peroxidation, the production of thiobarbituric acid reactive substances (TBARS) was measaured. Also, plasma low-density lipoprotein (LDL) were challenged with copper and the time course of lipid peroxidation was evaluated following the formation of conjugated dienes. The onset of TBARS generation induced by copper was marked delayed in both liver and brain microsomes from DHEA-treated animals. Also, the resistance of LDL to oxidation, expressed by the duration of the lag-phase of the kinetic curve, was significantly enhanced in DHEA-treated rats. Results indicate that in vivo DHEA supplementation makes subcellular fractions isolated from different tissues and plasma constituents (LDL) more resistant to lipid peroxidation triggered by copper. The antioxidant effect on plasma LDL might be of special relevance to the proposed antiatherogenic activity of DHEA. Moreover, multitargeted antioxidant activity of DHEA might protect tissues from oxygen radicals damage.     

The effect of exercise intensity on lipid peroxidation

This study characterizes exercise-induced lipid peroxidation during graded aerobic exercise in seven healthy men and women (36.4 +/- 3 yr). Levels of ethane and pentane in expired breath during cardiopulmonary exercise stress testing were measured at rest, lactic acidosis threshold (LAT), maximal exercise (VO2max), and recovery. Serum malonaldehyde (MDA) levels were measured at rest before exercise and 5 min after maximal exercise. Expired ethane and pentane flux levels were increased above resting levels at LAT, continued to rise at VO2max, then declined during recovery. Serum MDA levels were not significantly different before and after maximal exercise. Substantial exercise-induced lipid peroxidation (by expired ethane and pentane) apparently occurred in healthy individuals at LAT and continued to increase at VO2max, yet rapidly attenuated during post-exercise recovery. These findings indicate that in healthy individuals physical exercise induced lipid peroxidation transiently and that there was a removal of lipid peroxidation byproducts during recovery.     

The effect of undecaprenol on bilayer lipid membranes

The influence of undecaprenol on phosphatidylcholine macrovesicular bilayer lipid membranes has been studied by electrophysiological techniques. The current-voltage characteristics, ionic transference numbers, the membrane conductance-temperature relationships and the membrane breakdown voltage were measured. The permeability coefficients for Na+ and Cl- ions, the activation energy of ion migration across the membrane, the membrane hydrophobic thickness and the membrane Young's modulus were determined. Undecaprenol increases membrane conductance, membrane capacitance, membrane ionic permeability and membrane elastic deformability, decreases the activation energy, membrane hydrophobic thickness and membrane electromechanical stability, and does not change membrane selectivity. The formation by undecaprenyl molecules of fluid microdomains modulating membrane hydrophobic thickness is postulated. The data suggest that the behaviour of undecaprenol in membranes is regulated by transmembrane electrical potential.     

The effect of thermal trauma in mice on cytotoxicity of lymphocytes

Ten adult 18-month-old male fowls were vasoligated unilaterally just anterior to the cloaca via an incision made between the base of the tail and the cloacal orifice. Two birds each were killed at two weeks and four weeks post-ligation, and the remaining six birds at 12 weeks post-ligation. Forty per cent of the birds showed severe reactions in the ipsilateral testis, epididymal region and ductus deferens. The remaining birds showed slight gross changes and near normal histology. The contralateral organs in all birds were normal both macroscopically and microscopically.     

The effect of physical training on lipid parameters in the blood

Physical training leads to an improved metabolic capacity of musculature. At the same time through a decreased liberation of catecholamines a reduction of the increased lipolysis develops. The two factors together condition an improved glucose tolerance and a decrease of the reactive insulin secretion. Thus, among others, the synthesis of triglycerides is reduced and an essential factor of risk is favourably influenced for the development of arteriosclerosis.     

The effect of stevioside on glucose metabolism in rat

This study was conducted to determine the effect of stevioside (SVS) on glucose metabolism. The experiments were performed in male Wistar rats treated with SVS either by intravenous infusion or feeding. SVS infusion (150 mg/mL) was carried out in doses of 0.67, 1.00, and 1.33 mL.kg-1 body weight.h-1. The plasma glucose level significantly increased both during and after SVS infusion, whereas it was not affected by SVS feeding (13.3 mL.kg-1 body weight). The glucose turnover rate (GTR) of [14C(U)]glucose and [3(-3)H]glucose was not significantly different between control and SVS infusion animals. Percent glucose carbon recycling and glucose clearance were reduced from 28.7 +/- 1.3 to 23.0 +/- 1.6% (p < 0.05) and from 6.46 +/- 0.34 to 4.99 +/- 0.20 mL.min-1.kg-1 body weight (p < 0.01), respectively. The plasma insulin level did not change, whereas the plasma glucose level significantly increased from 120.3 +/- 5.9 to 176.8 +/- 10.8 mg% (p < 0.01) during SVS infusion. Animals pretreated with angiotensin II and arginine vasopressin showed no significant effect, while animals pretreated with prazosin had an attenuated hyperglycemic effect of SVS infusion. Pretreatment with indomethacin or N omega-nitro-L-arginine methyl ester (L-NAME) alleviated the plasma glucose level during the second period of SVS infusion. Pretreatment with the combination infusion of indomethacin and L-NAME reduced the plasma glucose level from 117.0 +/- 1.8 to 109.0 +/- 1.7 mg% (p < 0.001), and normalized the plasma glucose level in the second period of SVS infusion. Insulin infusion inhibited the hyperglycemic effect of SVS infusion. The present results show that the elevation of the plasma glucose level during SVS infusion is not due to the reduction of the insulin level. It is probably the effect of SVS on glucose transport across the cell. Insulin response to a high plasma glucose level is suppressed during SVS infusion. Several interactions among norepinephrine, prostaglandin, and nitric oxide are involved in modulating the hyperglycemia during SVS infusion.     

The effect of antioxidants on lipid metabolism in myocardium in experimental hyperthyroxinemic conditions

This experiment was conducted on 38 white Wistar-strain rats subdivided into five experimental groups. Group I were control animals which receiving intraperitoneal 0.5 ml injections of the sodium chloride physiological solution everyday during the whole experimental period of 26 days. Rats from Group II were injected intraperitoneally L-thyroxine (600 micrograms per kg of body weight) five times a week. The animals from Groups III, IV, and V, in addition to thyroxine injected in the same way as in Group II, were additionally administered one of such antioxidants as allopurinol, desferal, or vitamin C. The purpose of this research was to find an answer to the question whether the application of the above-mentioned antioxidants modifies the non-beneficial hyperthyroxinemic impact on the lipid metabolism of the cardiac muscle. It was found that the thyroxine influenced the change of the triglyceride and phospholipid contents in the cardiac muscle. All the applied antioxidants partly modified the thyroxine influence on the lipid balance in the cardiac muscle, especially in the area of triglycerides.     

Factors influencing rumen fermentation: effect of hydrogen on formation of propionate

The effect of hydrogen on fermentation of lactate, pyruvate, fumarate, and succinate by resting rumen microorganisms has been investigated. Under an atmosphere of nitrogen, lactate was fermented to yield acetate as the major product (85 to 100 mole %) and propionate (0 to 17 mole %) and butyrate (0 to 3%) as secondary products. Under hydrogen, there was increased formation of both propionate and total volatile fatty acids. The amount of propionate increased 4 to 8 times and total volatile fatty acids 2.5 to 3.2 times. Propionate formation was proportional to the hydrogen concentration and reached a maximum at a partial pressure of hydrogen of .2 N/m2. With [2-carbon-14] lactate, propionate was formed via the dicarboxylic acid pathway under both nitrogen or hydrogen. Hydrogen did not affect significantly the fermentation of pyruvate or succinate. With fumarate under hydrogen, propionate and total volatile fatty acids increased 6.8 and 2 times while acetate was unchanged. The mechanism by which hydrogen exerts these effects is discussed in relation to the role of methanogenesis in the rumen.     

The effect of anaesthetics on the dynamic heterogeneity of lipid membranes

A randomized multicenter study was performed in order to investigate the acceptance of a low-dose OC (30 micrograms of ethinyloestradiol and 150 micrograms of desogestrel), using a 9 weeks on and 1 week off schedule (prolonged regimen, n = 198), compared to a traditional 3 weeks on, 1 week off schedule (standard regimen, n = 96). Haemoglobin and blood pressure remained the same in both groups during the study. No significant differences were found in body weight changes between the two groups. There was significantly more breakthrough bleeding and spotting in the group with prolonged regimen than in the group with standard regimen, but both breakthrough bleeding and spotting decreased during the trial. Irregular bleeding was significantly less in women who were already using OC, compared to "new starters." No serious side effects occurred. Significantly more women stopped the trial because of bleeding problems in the group with prolonged regimen, while there were significantly more women who stopped the trial because of headache in the group with standard regimen. After completing 12 months, or after premature withdrawal from the study, each women completed a questionnaire. Sixty-three per cent of the women preferred the studied alternative and twenty-six per cent preferred the traditional OC.     

The effect of prolactin on the response of human lymphocytes to phytohaemagglutinin

Lymphocytes were collected from ten normal human males and incubated with or without phytohaemagglutinin (PHA) in the absence or presence of ovine prolactin in concentrations found in normal individuals and in human pregnancy. Prolactin consistently inhibited lymphocyte transformations. The degree of inhibition became progressively less as PHA concentrations were increased.     

The effect of aging on rat liver regeneration

The effect of age on hepatocyte mensuration and mitotic activity 48 h after partial hepatectomy was investigated in rats. Both age and partial hepatectomy had significant effects upon hepatocyte counts per microscopic field. The number of hepatocytes per microscopic field declined with age in the control groups of different advancing ages and in the experimental groups of advancing ages. There was essentially no mitotic activity in the livers of the control groups. However, mitotic counts were greatly increased in livers from those animals that were partially Hepatectomized; the increase in mitotic activity in the 13-month-old animals was double over that observed in both the very young and the very old.     

The hypotensive effect of cisapride in rat

1. Cisapride is a prokinetic agent believed to facilitate acetylcholine release from the myenteric plexus of the gut. The aim of the present study was to investigate the effect of cisapride on blood pressure and the effects of muscarinic receptor antagonists on the cisapride-induced blood pressure changes. 2. Cisapride was given i.v. alone or 10 min after muscarinic receptor antagonists. Cisapride given i.v. produced a significant decrease in blood pressure in a dose-related manner. Atropine, AF-DX 116 and 4-DAMP given 10 min before cisapride injection, partially inhibited the hypotensive response to cisapride. In pithed rat, the effect of cisapride on blood pressure remained unaltered. 3. This study indicates that the action of cisapride is not through central mechanisms and part of cisapride's effect is through the cholinergic system.