Effects of single sessions of low-intensity continuous and moderate-intensity intermittent exercise on blood lipids in the same endurance runners.

The factors responsible for the acute effects of exercise on blood lipids are not well known, and there have been few studies comparing different kinds of exercise in the same population. The concentration of blood lipids was evaluated in this study at the end and at post-24h of two 14km/90min single exercise sessions: continuous exercise (CE) at 44.5+/-5.6% VO(2max) and intermittent exercise (IE) at 39-72% VO(2max), in subjects with high levels of aerobic training. Fourteen male athletes (endurance runners) took part in this study and each completed a 24h dietary record. The O(2) uptake and CO(2) production were recorded, and blood lactate and blood lipids were measured. The results showed that triacylglycerols were not modified by any kind of exercise. Total cholesterol was increased at the end of both exercises: 7.04% for CE (p<0.001) and 4.23% for IE (p=0.001). High-density lipoprotein cholesterol was increased at the end of IE: 11.38% (p=0.03) and low-density lipoprotein cholesterol was increased only at the end of CE: 7.45% (p=0.006). The increase of lipids for CE was negatively correlated with aerobic fitness indicators (heart rate and %HRmax at lactate threshold), and was positively associated with energy expenditure. For IE, %HRmax and lactate were negatively correlated, and the respiratory exchange ratio was positively correlated, with the lipid increase. We conclude that in trained male athletes, a 14km run in 90min induced different changes of lipid profile if the exercise was done continuously or intermittently, and that in CE the extent of these increases was influenced by aerobic fitness.

Preventive effect of Spirulina maxima on the fatty liver induced by a fructose-rich diet in the rat, a preliminary report.

Cyanobacteria Spirulina maxima from Texcoco Lake in Mexico was administered as a 5% component of a purified diet, to Wistar rats together with a high percentage of fructose (60%) and its effect on several lipid fractions of plasma and liver was studied and compared to those of rats fed purified diets containing 60% of glucose or 60% of fructose. A preventive effect of Spirulina maxima on the fructose-induced increase of the liver triglycerides level was observed together with an elevation of the phospholipid concentration in this tissue. On the other hand Spirulina maxima produced a plasma cholesterol level even lower than that observed in the control group.

Effects of acute and chronic estrogenic treatment on vasomotor responses of aortic rings from ovariectomized rats.

The effects of either chronic or acute estrogenic treatment on the "in vitro" vasomotor responses to phenylephrine (10(-9)-10(-5) M) and to carbachol (10(-9)-10(-5) M) of aortic rings excised from ovariectomized rats were analyzed. Chronic estrogenic treatment consisted in a single subcutaneous dose of 1 mumol estradiol 17-stearate. Effects of acute estrogenic treatment were evaluated by recording the responses of aortic rings excised from untreated ovariectomized rats both before and after the addition of 17 beta-estradiol to the superfusing solutions. In order to identify the endothelium-dependent responses each experiment was performed simultaneously on pairs of rings from the same aorta, one with and the other without functional endothelium. The contractile responses to phenylephrine of endothelium-intact vessels were attenuated by chronic estrogenic treatment; this attenuation was further increased by preincubation of the vessels with indomethacin and was reverted by N omega-nitro-L-arginine methyl ester. Either chronic or acute estrogenic treatment enhanced the carbachol-induced endothelium dependent relaxation of phenylephrine-precontracted rings. The results may be explained by assuming that estrogens increase the basal release of both nitric oxide and a cyclooxygenase-dependent vasoconstricting prostanoid as well as the receptor-mediated release of nitric oxide from the endothelium of the rat aorta.

Spirulina maxima prevents fatty liver formation in CD-1 male and female mice with experimental diabetes.

The dietary administration of 5% Spirulina maxima (SM) during four weeks to diabetic mice, starting one week after a single dose of alloxan, 250 mg/Kg body weight, prevented fatty liver production in male and female animals. The main action of SM was on triacylglycerol levels in serum and liver. There was also a moderate hypoglycemia in male mice. The thiobarbituric acid reactive substances also decreased in serum and liver after SM administration. There was also a decrease in the percentage of HDL in diabetic mice that was reverted by the SM administration. The sum of LDL + VLDL percentages was also partially normalized in diabetic animals by the SM administration. An additional observation was the lower incidence of adherences between the liver and the intestine loops in the diabetic mice treated with SM compared with diabetic mice without SM. Male and female mice showed differences to diabetes susceptibility and response to SM, the female being more resistant to diabetes induction by alloxan and more responsive to the beneficial effects of SM. It is worth future work of SM on humans looking for better quality of life and longer survival of diabetic patients.

Effects of dietary Spirulina maxima on endothelium dependent vasomotor responses of rat aortic rings.

The aim of this study was to evaluate the effects of Spirulina maxima on vasomotor responses of aorta rings from male Wistar rats fed on a purified diet. For this purpose, the animals (weighing 200-240 g) were allocated randomly in two groups. One receiving purified control diet (A) and the other receiving purified diet containing 5% Spirulina (B). Purified diets were according to American Institute of Nutrition guidelines and adjusted to Spirulina protein content. All animals were fed (20 g/day/rat) during two weeks, receiving water ad libitum and 12 h. light-dark cycles. Spirulina maxima effects were evaluated by concentration-response (CR) curves of aorta rings with or without endothelium to phenylephrine (PE), both in presence and absence of indomethacin (Indom) or indomethacin plus L-NAME (Indom. + L-NAME), and to carbachol (CCh). Aorta rings with endothelium from group B showed, relative to corresponding rings from group A: 1) a significant decrease in the maximal tension developed in response to PE. 2) this decrease was reverted by Indom. 3) Indom. + L-NAME induced an additional increase in the contractile responses to PE. 4) a significant shift to the left of the CR curve to CCh. No significant differences were observed in the tension developed in response to PE in rings without endothelium from either group. These results suggest that Spirulina maxima may decrease vascular tone by increasing the synthesis and release of both a vasodilating cyclooxygenase-dependent product of arachidonic acid and nitric oxide, as well as by decreasing the synthesis and release of a vasoconstricting eicosanoid from the endothelial cells.

Comparative toxicity of high doses of vastatins currently used by clinicians, in CD-1 male mice fed with a hypercholesterolemic diet.

The CD-1 male-mouse model was employed to evaluate comparatively the toxicity of four vastatins (VTS) currently used in clinical medicine: lovastatin (LVT), simvastatin (SVT), pravastatin (PVT) and fluvastatin (FVT). Each vastatin was used orally in doses of 500 mg/Kg body weight/day, in animals with a hypercholesterolemic diet (HD) 5 days, or with a control diet (CD) 30 days. The association of high doses of VTS + HD produced a significant increase in liver weight and liver weight to body weight ratio in animals with SVT and FVT. Cholesterol (Chol) and triacylglycerols (TAG) in the liver increased significantly with FVT but not with the other VTS; Chol increased and TAG decreased in serum very significantly with FVT and SVT. The serum aminotransferases increased quite significantly with FVT but not with other VTS. In the experiment with high doses of VTS + CD, the animals receiving SVT or FVT showed a moderate loss of body weight. Liver weight and liver weight to body weight ratios were similar among all groups. Liver Chol showed a significant decrease with all VTS. Serum Chol decreased moderately with LVT and FVT. TAG in serum and liver showed a moderate decrease with all VTS. The serum aminotransferases were not modified by any vastatin. Our results indicate that high doses of VTS in male mice with a hypercholesterolemic diet result in a decreasing toxicity as follows: FVT>SVT>LVT>PVT.

High lovastatin doses combined with hypercholesterolemic diet induce hepatic damage and are lethal to the CD-1 mouse.

The addition of 1% lovastatin (LVT) to hypercholesterolemic diets [1% cholesterol or 1% cholesterol plus 0.1% sodium deoxycholate (HD)] induced hepatic damage and was lethal to CD-1 mice in the first days of treatment; the females were more resistant than males. LVT or HD administered alone was harmless to male or female mice. After a 3-day treatment all groups that received LVT (1%, 0.1% or 0.05%) plus HD showed a higher percentage of liver weight, with respect to whole body weight. Cholesterol serum levels increased in males with HD, but remained low in female mice. In the liver, total lipids and cholesterol levels increased in male mice with HD, but cholesterol remained unchanged in females. The addition of LVT to HD prevented the increase of serum and liver cholesterol levels in male mice. These results allow us to propose the CD-1 male-mouse as a model to evaluate the toxicity of LVT or other vastatins.

Arthrospira maxima prevents the acute fatty liver induced by the administration of simvastatin, ethanol and a hypercholesterolemic diet to mice.

An evident fatty liver, corroborated morphologically and chemically, was produced in CD-1 mice after five daily doses of simvastatin 75 mg/Kg body weight, a hypercholesterolemic diet and 20 percent ethanol in the drinking water. After treating the animals, they presented serum triacylglycerols levels five times higher than the control mice, total lipids, cholesterol and triacylglycerols in the liver were 2, 2 and 1.5 times higher, respectively, than in control animals. When Arthrospira maxima was given with diet two weeks prior the onset of fatty liver induction, there was a decrement of liver total lipids (40%), liver triacylglycerols (50%) and serum triacylglycerols (50%) compared to the animals with the same treatment but without Arthrospira maxima. In addition to the mentioned protective effect, the administration of this algae, produced a significant increase (45%) in serum high density lipoproteins. The mechanism for this protective effect was not established in these experiments.

Comparative analysis of erythrocyte fatty acid composition in a sample of Mexico City children and young adults on a free diet.

In the present study the influence of age on red blood cell fatty acid (RBCFA) composition was analyzed in a sample of Mexico City children and young people on a free diet, as there is scarce information about RBCFA composition in the Mexican population. Erythrocyte lipids were extracted with isopropyl alcohol and fatty acid methyl esters were prepared to be analyzed by gas liquid chromatography. The 1- to 2-year-old group showed a higher percent level of C18:0 (34.75 +/- 2.5 vs. 29.67 +/- 1.3, p < 0.002) and lower of C16:1 (0.58 +/- 0.2 vs. 1.09 +/- 0.2, p < 0.05), C20:4 (14.08 +/- 4.1 vs, 18.20 +/- 1.2, p < 0.05) and C22:5 (2.79 +/- 1.7 vs. 7.68 +/- 0.8, p < 0.001) than the 20- to 25-year-old group. Both groups showed a very low linoleic acid proportion, children 0.48% and young adults 0.54%. The unsaturated/saturated fatty acid ratio was found to be 0.55 +/- 0.2 in children and 0.91 +/- 0.1 in adults (p < 0.001). These findings indicate the presence of factors related to age that affect the fatty acid composition in the erythrocyte membrane different from diet habits in the sample analyzed. Results are compared with reports in the literature.

Steroid metabolism in granulosa and theca interna cells from preovulatory follicles of domestic hen (Gallus domesticus).

The capability of granulosa and theca interna cells, from preovulatory follicles of the domestic hen, to metabolize steroid precursors was evaluated. Granulosa and theca interna cells were isolated from ovarian preovulatory follicles at three different developmental stages: F1, F3 and F5. Tritiated pregnenolone (P5), progesterone (P4), dehydroepiandrosterone (DHEA), androstenedione (A4) and testosterone (T) were employed as precursors and their metabolic products were evaluated. The major metabolite of P5 by granulosa cells was P4, but we also observed low amounts of 5beta-pregnandione. DHEA metabolism by granulosa cells yielded mainly A4, and minute quantities of 5beta-androstan-3,17-dione (5beta-dione) were detected. The only significant metabolite obtained in granulosa cells from A4 was 5beta-dione, whereas T was only transformed into A4. On the other hand, P5 metabolism by theca interna cells yielded A4 as the main product, also P4, 17alpha-OHP4, 17alpha-OHP5, 5beta-pregnandione, and DHEA, were found. When DHEA was the precursor A4 was produced in higher amounts than 5beta-dione. A4 was mainly transformed into 5beta-dione. In similar conditions, T was transformed into A4. These results show that granulosa cells have enzymatic activities of 3beta-hydroxysteroid dehydrogenase/5-4 isomerase (3beta-HSD from P5 and DHEA), 17beta-hydroxysteroid dehydrogenase (17beta-HSD from T) and 5beta-reductase (from P5, DHEA and A4). Whereas theca interna cells have enzymatic activities of cytochrome P450c17 (from P5 and P4), 3beta-HSD (from P5 and DHEA), 17beta-HSD (from T) and 5beta-reductase (from P4, DHEA and A4). These data support the concept that theca interna cells have the ability to synthesize androgens from progestins produced in granulosa cells. In addition, since theca interna cells did not show the capacity to aromatize androgens suggests that interaction between theca interna and theca externa cells occurs in vivo, thus confirming the three cell model for estrogen production. Furthermore, the fact that other metabolites were produced both in granulosa and theca interna cells, but in a different extent, suggests that complex mechanisms are participating in the regulation of steroid synthesis in avian ovary follicles.

Hypoglycemic action of Cucurbita ficifolia on Type 2 diabetic patients with moderately high blood glucose levels.

Ten Type 2 diabetic patients with moderately hyperglycemia, received a raw extract of Cucurbita ficifolia or potable water in a single dose of 4 ml/Kg body weight, in two different sessions at least separated by 1 week. Blood glucose levels were followed in both parts of the study by a period of 5 h. The patients had stopped their pharmacologic medication 24 h prior to each part of the study. As expected, no significant changes on blood glucose were observed after giving the vehicle; however, the oral administration of C. ficifolia was followed by a significant decrease in blood glucose levels, from 12.07+/-1.69 mM (217.2+/-30.4 mg/dl) to 9.42+/-1.96 mM (169.6+/-35.3 mg/dl) 3 h after and to 8.37+/-1.74 mM (150.8+/-31.3 mg/dl) 5 h after the extract administration. The hypoglycemic action of Cucurbita ficifolia agrees with its effects previously observed in laboratory animals. The results of this preliminary study do not give indications for the mechanism of this hypoglycemic effect.

Endothelium-dependent effects of the ethanolic extract of the mistletoe Psittacanthus calyculatus on the vasomotor responses of rat aortic rings.

The mistletoe Psittacanthus calyculatus (Loranthaceae) is used in Mexican traditional medicine for the treatment of hypertension. In the present study the effects of a crude ethanolic extract of this mistletoe, on the vasomotor reactivity of superfused rat aortic rings (with or without a functional endothelium) were analyzed. Either in the absence or in the presence of L-NAME or indomethacin, the extract (12.5-800 microg/ml) had no effect on the basal tone of both types of rings. In phenylephrine-precontracted rings, low concentrations of the extract (up to 300 microg/ml) induced a small additional tension development in both types of rings; however, the tension increase was slightly larger in rings having an intact endothelium. At higher concentrations (400-800 microg/ml), the extract relaxed, concentration-dependently, phenylephrine-precontracted rings with an intact endothelium. This relaxation was completely reverted by the addition of L-NAME. When the extract was applied in the continuous presence of L-NAME to phenylephrine-precontracted rings, instead of a relaxation a marked additional tension development occurred. Indomethacin did not modify the relaxation induced by the extract. The results indicate that the ethanolic extract of this mistletoe induces, predominantly, an endothelium-dependent relaxation which seems to be mediated by the synthesis/release of nitric oxide.

Studies on the preventive effect of Spirulina maxima on fatty liver development induced by carbon tetrachloride, in the rat.

The aim of the present work was to assess if the feeding of either the oil extract of Spirulina maxima or of its defatted fraction would prevent fatty liver development, induced in rats by a single intraperitoneal dose of carbon tetrachloride (CCl4). Liver and serum lipids were evaluated 4 days after treatment with this agent. Concentration of liver lipids did not differ in rats fed on a purified diet either without or with one of the fractions of Spirulina, except for total cholesterol, which showed a slight increase in the group receiving the oil extract of Spirulina. However, after CCl4 treatment, liver total lipids and triacylglycerols were significantly lower in rats fed on a diet containing any fraction of Spirulina (defatted or the oil fraction) than in rats without Spirulina in their diet. Furthermore, the increased liver cholesterol values, induced by CCl4 treatment, were not observed in rats receiving Spirulina. In addition, rats receiving whole Spirulina in their diet and treated only with the vehicle showed an increase in the percentage of HDL values. The changes in VLDL and LDL induced by CCl4 treatment were not observed in the whole Spirulina group. Furthermore, after CCl4 treatment the values of the liver microsomal thiobarbituric acid-reactive substances were lower in the whole Spirulina group than in the control group. These results support the potential hepatoprotective role of Spirulina.

Effects of the ethanolic extract of Spirulina maxima on endothelium dependent vasomotor responses of rat aortic rings.

Dietary Spirulina decreases, endothelium-dependently, the responses to vasoconstrictor agonists and increases the endothelium-dependent, agonist-induced, vasodilator responses of rat aorta rings. The aim of this study was to analyze, in vitro, the effects of a raw ethanolic extract of Spirulina maxima on the vasomotor responses of rat aortic rings to phenylephrine and to carbachol. On rings with endothelium, the extract produced the following effects: (a) a concentration-dependent (60-1000 microg/ml) decrease of the contractile response to phenylephrine; (b) a rightward shift and a decrease in maximal developed tension, of the concentration--response curve to phenylephrine; (c) a concentration dependent relaxation of phenylephrine-precontracted rings. These effects were blocked by L-NAME, and not modified by indomethacin. The extract had no effect on the concentration-response curve to carbachol of rings with endothelium. On endothelium-denuded rings the extract caused a significant rightward shift of the concentration response curve to phenylephrine without any effect on maximal tension development. In the presence of the extract, indomethacin induced a marked decrease in the maximal phenylephrine-induced tension of endothelium-denuded rings. These results suggest that the extract increases the basal synthesis/release of NO by the endothelium and, also, the synthesis/release of a cyclooxygenase-dependent vasoconstricting prostanoid by vascular smooth muscle cells.

[Erythrocyte fatty acids in children with severe protein-calorie malnutrition]. / Los ácidos grasos eritrocíticos de niños con desnutrición energético proteica grave.

In this study we analyzed the erythrocyte fatty acid (FA) composition in Mexican children, from 4 to 21 months old with advanced protein-calorie malnutrition. We tried to establish if there were differences in the erythrocyte FA composition of these subjects in comparison with normal children of the same age. The major FA found in children with protein-calorie malnutrition and their controls were (in percentage): stearic (30.6 +/- 5.4 vs 34.8 +/- 2.5), palmitic (22.7 +/- 3.1 vs 25.8 +/- 2.5), oleic (15.9 +/- 3.8 vs 13.1 +/- 3.0), arachidonic (14.8 +/- 4.4 vs 14.1 +/- 4.1), decosatetraenoic (2.4 +/- 2.0 vs 3.7 +/- 2.1) and docosapentaenoic (3.9 +/- 2.2 vs 2.8 +/- 1.7), respectively. There were no intergroup statistical differences in the individual FA between the undernourished and control groups. Saturated FA were 53.2 +/- 6.8% vs 60.6 +/- 7.2%, monounsaturated FA 17.0 +/- 4.1% vs 13.7 +/- 3.0% and polyunsaturated FA 23.7 +/- 5.5% vs 21.1 +/- 4.8% for undernourished and control groups, respectively. Long-chain unsaturated FA values presented the highest variation in both groups, i.e. the unsaturated/saturated FA ratio was 0.76 +/- 0.2 for the undernourished and 0.53 +/- 0.2 for the control group (p < 0.05). Thus, the higher unsaturated/saturated FA ratio in the undernourished was the only change in erythrocyte FA composition observed.

Acute physiological response to indoor cycling with and without hydration; case and self-control study.

INTRODUCTION: Oral rehydration drinks help maintain physical capacity and hydration during exercise. OBJECTIVE: Evaluate, in a case and self-control study, the effectiveness of three hydration and exercise protocols on work capacity and physical and psychosomatic stress during indoor cycling (InC). METHODS: 14 middle-aged eutrophic men participated in three controlled randomly and not sequentially hydration (~278 mL 6/c 15 min) and exercise (InC/90 min) protocols: No liquids, plain water, or sports drinks (SD). The response variables were: Body temperature (BT), heart rate (HR), and mean blood pressure (MBP). The covariables: Distance traveled (DT), ergometer resistance (R), body fat (BF), difference in body weight between tests (rBW), and age of the participants. The differences between protocols were evaluated using GLM Repeated Measures, the independence of associations by multiple linear regression. RESULTS: In non-liquids, the subjects showed higher BT, HR, and MBP than when they drank plain water or SD (p < 0.01). Work capacity was the same in the three hydration protocols. BT was the most sensitive variable detected by the hydration status of the subjects. 34%, 99%, and 21% of the associated variance to HR, MBP, and BT was explained by DT + BT, BT + BF, and ΔBW + age + R + DT + BF, respectively. CONCLUSIONS: Liquid intake with or without electrolytes does not affect work capacity, and they are equally effective as hydration sources during =?90 min of InC at strong and very strong intensities. Body temperature is the most sensitive variable detected by the subject's hydration status during exercise.

Introducción: Las bebidas de re-hidratación oral ayudan a mantener la capacidad física y el nivel de hidratación durante el ejercicio. Objetivo: Evaluar en un estudio de casos y autocontroles la efectividad de tres protocolos de hidratación y ejercicio sobre la capacidad de trabajo, estrés físico y psicosomático durante el ciclismo de sala (CiS). Métodos: 14 varones eutróficos de mediana edad participaron de manera aleatoria y no consecutiva en tres protocolos de hidratación controlada (~278 mL 6/c 15 min) y ejercicio (CiS/90 min): No líquidos, agua corriente o bebida deportiva (BD). Las variables respuesta fueron: Temperatura corporal (TC), frecuencia cardiaca (FC) y presión sanguínea media (PSM). Las covariables: distancia recorrida (DR), resistencia del ergómetro (R) grasa corporal (GC), pérdida de peso al final del ejercicio ( PC) y edad de los participantes. Las diferencias entre los protocolos fueron evaluadas por GLM de Medidas Repetidas, la independencia de las asociaciones por regresión lineal múltiple. Resultados: En no líquidos, los sujetos presentaron mayor TC, FC y PSM que cuando ingirieron agua corriente o BD (p < 0,01). La capacidad de trabajo fue igual en los tres protocolos de hidratación. La TC fue la variable más sensible que detectó el estado de hidratación de los sujetos. El 34%, 99% y 21% de la varianza asociada a FC, PSM y TC lo explicaron DR + TC, TC + GC, y ?PC + edad + R + DR + GC respectivamente. Conclusiones: La ingesta de líquidos con o sin electrolitos no afecta la capacidad de trabajo y son igualmente efectivos como medios de hidratación durante =?90 min de Cis a intensidades pesadas y muy pesadas. La TC es la variable más sensible que detecta el estado de hidratación de los sujetos durante el ejercicio.

Effects of dietary Spirulina on vascular reactivity.

There are several reports suggesting that Spirulina (Arthrospira) may have a beneficial effect in the prevention of cardiovascular diseases. Here we review the results of studies on the effects of dietary Spirulina on the vasomotor reactivity of aortic rings excised from either lean or obese Wistar rats. We also review preliminary results on the effects of Spirulina intake on plasma lipids and blood pressure in humans. The results of the former studies strongly suggest that Spirulina induces a tone-related increase in the synthesis/release of nitric oxide by the endothelium as well as an increase in the synthesis/release of a vasodilating cyclooxygenase-dependent metabolite of arachidonic acid and/or a decrease in the synthesis/release of a vasoconstricting eicosanoid by the endothelium. In humans, Spirulina maxima intake decreases blood pressure and plasma lipid concentrations, especially triacylglycerols and low-density lipoprotein-cholesterol, and indirectly modifies the total cholesterol and high-density lipoprotein-cholesterol values.

Steroid metabolism in the cortex and the medulla of the early fetal bovine ovary.

Suspensions of cells obtained from the cortex and the medulla of the ovary of early bovine fetuses of 4-10 cm in crown-rump (C-R) length were used for studies of the metabolism of radiolabeled exogenous steroid precursors. Tritiated dehydroepiandrosterone, androstenedione, and testosterone were employed as precursors and their metabolic products were evaluated after separation by thin-layer chromatography. The extent of conversion of tritiated dehydroepiandrosterone to androstenedione was higher in cells from medulla than in those from the cortex. Androstenedione was metabolized mainly to estrone, and the percent of transformation was similar in the cortex and the medulla, but the rate of formation of 17 beta-estradiol was higher in the medulla than in the cortex. Furthermore, cells obtained from the cortex and the medulla aromatized testosterone to 17 beta-estradiol at a similar rate. In all cases, the percent of transformation was higher in ovaries from fetuses of 4.0 cm in C-R length than those from fetuses of 9.0-10.0 cm in C-R length. These data suggest that, in the bovine fetal ovary, the activity of 3 beta-hydroxysteroid dehydrogenase/isomerase and 17 beta-hydroxysteroid dehydrogenase predominates in the medulla, whereas aromatase activity is similar in the cortex and the medulla of the early fetal bovine ovary.

In vivo and in vitro studies of hypocholesterolemic effects of diosgenin in rats.

There is evidence that diosgenin when given orally or parenterally decreases cholesterol plasma levels in rat, chicken and rabbits that have had a diet-induced hypercholesterolemia. 2. The per-oral administration of [3H]diosgenin yielded 12% of the given dose distributed throughout: liver, spleen, epididymal fat, brain and carcass of the rat. 3. In everted gut sacs, [3H]diosgenin was better absorbed than cholesterol. 4. In these tests diosgenin was recovered esterified from the tissues and the recovered cholesterol showed less esterification in the presence of diosgenin than in its absence.

Identification of steroidogenic cell subpopulations in the ovary of the newly hatched chicken.

The aim of the present study is the isolation of subpopulations of steroid-producing cells in the ovary of the newly hatched chicken. Cells were obtained by fractional trypsin dissociation of the ovary and isopycnic separation in a continuous metrizamide gradient (0-30%). Testosterone and 17 beta-estradiol secretion was measured by radioimmunoassay in the incubation medium of the isolated cells. Six fractions of ovarian cells were studied. Fraction II (density 1.080) contained typical steroidogenic cells with a positive reaction for 3 beta-hydroxysteroid dehydrogenase, delta 5-isomerase. This fraction secreted testosterone (3.7 ng/10(6) cells/2 hr) but no 17 beta-estradiol secretion was detectable. The majority (85%) of cells obtained in fraction VI (density 1.150) were relatively undifferentiated and contained polyribosomes, mitochondria with lamellar cristae, and few rough endoplasmic reticulum; only 3-5% of the cells of this fraction were similar to those of fraction II. In fraction VI the highest level of 17 beta-estradiol secretion was found (2.9 ng/10(6) cells/2 hr) whereas testosterone was at a minimum level (0.06 ng/10(6) cells/2 hr). Results strongly suggest the existence of two cell subpopulations in the inmature chicken ovary: typical steroidogenic and poorly differentiated cells which secrete testosterone and 17 beta-estradiol, respectively.