Biomedical subjects

U Sod-Moriah

Publications and source records attributed to U Sod-Moriah.

6 recordsLinked to original sources

PubMed2000

Soluble polysaccharide and biomass of red microalga Porphyridium sp. alter intestinal morphology and reduce serum cholesterol in rats.

The present study investigated the effects of the red microalga Porphyridium sp. on gastrointestinal physiology and lipid metabolism in male Sprague-Dawley rats. Diets containing dietary fibre from pelleted red microalgal cells (biomass) or their sulfated polysaccharide, pectin or cellulose (control) were fed to rats for a period of 30 d. All three fibre-supplemented diets increased the length of both the small intestine and colon, with a significantly greater effect in rats fed the algal polysaccharide. The polysaccharide also increased mucosa and muscularis cross-sectional area of the jejunum, and caused hypertrophy in the muscularis layer. The algal biomass significantly lowered gastrointestinal transit time by 44% in comparison with the control rats. Serum and mucosal cholecystokinin levels were lower in rats on the pectin and polysaccharide diets, while cholecystokinin levels in rats fed algal biomass were not different from those in the control animals. In comparison with the control diet, all the experimental diets significantly lowered serum cholesterol levels (22-29%). Feeding of non-fermentable algal polysaccharide or biomass significantly increased faecal weight and bile acid excretion compared with pectin-fed or control rats. The algal polysaccharide and biomass were thus shown to be potent hypocholesterolaemic agents active at low concentrations in the diet. Both metabolic and morphological changes were observed following consumption of algae, suggesting several possible mechanisms by which the alga affects lipid metabolism. The results presented in the present study encourage the use of red microalga as a functional food.

Analysis of Variance↗

PubMed1990

Estrous cycle irregularities in overfed rats.

Hypothalamic and genetic obesities in rodents are usually associated with reproductive impairments, but the underlying etiology of the latter is not clear because of concomitant metabolic abnormalities in these animal models. In the present study metabolically intact rats were used and obesity was developed by offering the rats a cafeteria-type diet. Purina chow-fed animals were used as control. Cafeteria feeding was associated with hyperphagia and an increased brown adipose tissue (BAT) thermogenesis, in association with long estrous cycles (p less than 0.01). The latter was accounted for by a long diestrous phase (p less than 0.02). Replacement of the cafeteria diet with purina rat chow corrected the estrous cycle irregularities, as caloric consumption and body weight were reduced. We propose, as a working hypothesis, that reproductive functions are finely tuned with body temperature, and that an excess feeding-induced BAT thermogenesis may underlie the disruption in estrous cycle observed during overfeeding.

Adipose Tissue, Brown↗

PubMed1990

Role of midcycle FSH surge in follicular development.

The present study was undertaken to examine the importance of the proestrous surge of FSH for follicular development during the following cycles in the rat. The midcycle FSH surges were blocked in several consecutive cycles (1-5) by injecting proestrous rats with pentobarbital. The rats were sacrificed on the day of proestrus following the appropriate number of blocked FSH surges and their ovaries were removed for either direct measurements or for histological workout. The number and diameter of follicles were determined in the excised ovaries. Two or three cycles of barbiturate treatment reduced the number and diameter of the follicles. No large follicles (greater than 0.4 mm) were observed in the ovaries of rats in which four or five gonadotropin surges were blocked. A repeat experiment with concomitant supplementary hCG administration yielded the same results. Addition of exogenous FSH canceled the effect of pentobarbital. The cohort observed on ovaries after four cycles of treatment with pentobarbital and FSH resembled that observed in control rats. Histological measurements supported the results obtained with fresh ovaries. It is therefore suggested that in the third cycle preceding the ovulatory one, the midcycle FSH surge determines which follicles will be able to adequately develop in the following three cycles. In the cycle preceding the ovulatory one, the midcycle FSH peak 'rescues' a group of follicles and prepares them for a proper response to the FSH elevation taking place at the beginning of the subsequent ovulatory cycle. This process allows the selection of the dominant follicles which will respond by ovulation to the ensuing LH peak.

Animals↗

PubMed1986

Effects of acarbose in rats are influenced by the type of dietary starch.

When rats consume a high cornstarch (raw) diet containing the alpha glucosidase inhibitor acarbose, they transport a large portion of the undigested starch into the large bowel, causing massive distention of the lower GI tract. In the present study we compare the effects of acarbose (50 mg per 100 g diet) when mixed in a raw cornstarch diet to its effects when mixed in a cooked cornstarch diet of otherwise identical composition. Controls received the respective diets but without the drug. In contrast to its effects when mixed in the raw cornstarch, mixed in the cooked cornstarch diet, acarbose consumption was not accompanied by any significant fecal losses of dietary starch. The intestinal distention induced by the drug was also much smaller in the rats eating the cooked cornstarch than the raw cornstarch. When either diet contained acarbose, fat depot weights were significantly lower than when the diets did not contain the drug. However, the difference was consistently greater with the raw cornstarch diet.

Acarbose↗

PubMed1986

Hormonal effects of ketoconazole in vivo in the male rat: mechanism of action.

Ketoconazole, an antifungal agent, has been shown to lower serum testosterone (T) in man. Measurements of circulating precursors of T suggest that ketoconazole may inhibit 17,20-desmolase activity in the testis. To further elucidate its mechanism of action in vivo, we studied its effects on the pituitary-gonadal axis in the male rate. Two groups of normal male Sprague-Dawley rats were treated with either oil or 25 mg ketoconazole in oil by im injection every 8 h for 21 days. Serum ketoconazole concentrations in the rat 2 h after the 25-mg dose were similar to those after oral administration of a much lower (1/33rd) dose to man. Ketoconazole treatment led to 50% suppression of serum T and prostate and seminal vesicle weights. Testis weights were not significantly affected. Intratesticular T concentrations showed a 50% decrease below the control level. Testicular 17 alpha-hydroxylase, 17,20-desmolase, and 17 beta-hydroxysteroid dehydrogenase activities in the ketoconazole-treated animals were significantly decreased in proportion to the decreases in serum and intratesticular T concentrations. Elevations of serum LH and FSH concentrations in the ketoconazole-treated rats were not proportionate to the decline in serum T concentration. Therefore, to exclude an additional inhibitory effect of ketoconazole at the pituitary level, we treated two groups of castrated male Sprague-Dawley rats with the same dose of ketoconazole or oil for 3 days. Serum LH and FSH concentrations were not significantly different in the two groups. In separate experiments, combined treatment of intact rats with GnRH agonist and ketoconazole for 21 days led to lower mean serum T concentrations and accessory organ weights than those achieved with either agent alone. We conclude that ketoconazole inhibits T synthesis, primarily by inhibiting the activity of multiple enzymes in the T biosynthetic pathway and has no direct effect at the pituitary level; ketoconazole metabolism in the rat is considerably different from that in man; and ketoconazole enhances the inhibitory effects of GnRH agonist.

Aldehyde-Lyases↗

PubMed1982

Excretion of ammonia by rat kidney during metabolic alkalosis.

In rat kidney, proximal tubular and final urinary ammonia concentration are finite. They are lower in animals with metabolic alkalosis than in controls. A positive correlation between ammonia concentration and water removal (as indicated by fluid to plasma ratios for inulin) was found. A comparison of tubular fluid to plasma concentration ratios for inulin and ammonia indicates that more ammonia enters proximal tubular fluid than appears in the final urine. These observations indicate that ammonia is probably secreted primarily at the level of the proximal tubule and then undergoes reabsorption at distal sites of the nephron.

Alkalosis↗