The circadian rhythm in activity of the periodic acid Schiff reaction and of the Mg and Ca content in rat liver in relation to age and season of the year.

The experiments were carried out on male Wistar rats aged 6, 12 and 24 months, over the four seasons of the year. Analysis of the results obtained in all age groups disclosed that changes in activity of the p.a.S (periodic acid Schiff) reaction and in concentrations of Mg and Ca in the liver showed rhythmic oscillations with a period of 12 hours. The maximal p.a.S reaction activity and of Ca and Mg levels were generally found to coincide throughout all seasons and in all age groups. The rhythms of change in these parameters in 12- and 24-month-old rats showed a phase shift as compared to the 6-month-old animals.

Circadian variation of mitochondrial succinic dehydrogenase and microsomal cytochrome P-450 dependent monooxygenase activity in the liver of sexually immature and mature rats.

The experiments were carried out on 60-day and 6-month old male Wistar rats within 48 h in one season of the year (autumn). Material was collected every four hours, beginning from 10:00 a.m. The present results indicate that the fluctuations of cytochrome P-450 content in liver microsomes in both age groups occurred in a 12 h rhythm with peaks at 10:00 and 22:00. Similarly, the activity fluctuations of NADPH-cytochrome c reductase showed the 12 h rhythm, with maximal values at 10:00 and 22:00, too. The cytochrome b5 content in a younger group of rats oscillated apparently in the 12 h rhythm with the maximal values at 06:00 and 18:00. The activity course of cytochrome b5 in 6-month-old rats revealed a 24 h rhythm and two maxima of the activity were found: the first one at 14:00 and the second one at 02:00. NADH-cytochrome b5 reductase in both age groups showed a 24 h rhythm, also the activity fluctuations of succinic dehydrogenase showed a tendency to 24-h rhythmicity, and the differences between minimal and maximal values were statistically insignificant. The results of our experiment have shown some correlations between the activity of microsomal system of mixed-function oxidases and mitochondrial respiratory enzyme.

Effect of cadmium upon the activity of some selected marker enzymes in rat liver.

The aim of this study was to determine activities of selected enzymes, i.e. Mg(++)-stimulated ATP-ase, acid phosphatase (AcP), esterase and succinate dehydrogenase (SDH) in rat liver after intragastric administration of cadmium chloride. The investigations were performed on forty male rats, Wistar strain, which made up one control group and two experimental groups. The rats of one experimental group were given a single dose of cadmium chloride solution of 88 mg CdCl2 per kg body weight (Group I), whereas the other experimental group received a double dose, i.e. 176 mg CdCl2 per kg body weight (Group II). The activities of enzymatic reactions were determined by means of analysis of surface optical density using the image computer analyzer, whereas the degree of mental accumulation was estimated with atom absorption spectrophotometry. Following cadmium chloride administration, the activities of SDH and esterase decreased in both experimental groups compared to controls. The decrease in both enzymatic activities was statistically significant. Similarly, activities of ACP and Mg(++)-stimulated ATP-ase decreased below control level in the rats of the Group I, which were given lower dose of CdCl2. This change was not statistically significant. Higher dose of CdCl2 (Group II) caused a statistically significant increase in acid phosphatase activity and only a small increase (bearing no statistical significance) in Mg(++)-stimulated ATP-ase activity. In addition, it was found that the accumulation of cadmium in both the liver and the kidneys is dose-related.

Changes of enzyme activity in the rat liver at different age in circadian cycle.

Most of the biological processes in the living organisms of both animals and man are known to be of rhythmical nature. Variability of enzymatic activity in circadian cycle depends on many factors among other on age, sexual maturity, diet as well as medication. The results obtained in our studies indicate, that the activity changes of acid phosphatase and ATP-ase Mg++ dependent in the liver of all the examined age groups were of 24 hour circadian rythm. As to the acid phosphatase activity the results of this experiments showed that in circadian cycle in all examined age groups there is only one peak of elevated activity. ATP-ase Mg++ dependent showed two activity peaks appearing at the same hour both in 30 and 60 days old animals. It should be noticed that the activities of ATP-ase Mg++ dependent in 100 day old animals were two times higher than in 30 and 60 days old rats.

Effect of dietary fats on experimental hypertension.

In an experiment on 95 Wistar rats weighing 330 g the effect was studied of partially hydrogenated marine oil and cod-liver oil as well as sunflowerseed oil and animal fat on arterial hypertension induced with administration of 1.5% NaCl in drinking water. During 5 weeks the animals received diets containing 37.8 kcal% derived from the studied fats. After the first week of 1.5% NaCl solution administration a significant rise of the systolic blood pressure and heart rate was observed in all animals without regard to the fat received by them with the diet. The rise of the blood pressure was greatest in the group of rats kept on the diet with animal fat, while in the groups of rats receiving diets with sunflowerseed oil or marine oils this rise was significantly smaller, especially with cod-liver oil. The hypotensive effect of marine oils, particularly cod-liver oil, was more pronounced than that of sunflowerseed oil. The hypotensive effect of partially hydrogenated fish oil was less pronounced than that of cod-liver oil. Our experiments demonstrated a significant effect of the amount of dietary fat on the development of experimental hypertension. Greater intake of salt and animal fats in human diet may be one of the causes of essential hypertension.

Effect of long-term diet enrichment with selenium, vitamin E and vitamin B15 on the degree of fatty infiltration of the liver.

In a two-year experiment on 190 Wistar rats the effects were studied of the aging process and diet enrichment with selenium, vitamin E and vitamin B15 (pangamic acid) on the degree of fatty infiltration of the liver determined histochemically with Oil Red O. The degree of fatty infiltration of the liver was assessed by the method of quantitative analysis using a computer image analyser Quantimet 720. System 30 (Cambridge Instruments). The process of aging of the animals was associated with increasing fatty infiltration of the liver. Selenium had a two-phase effect on the degree of fatty infiltration: in the first 12 months of selenium administration (0.1 ppm of sodium selenite per 100 g of the diet) fatty infiltration of the liver was decreasing, and after 18 months of the experiment this effect disappeared and the degree of fatty infiltration was not different from that in the control group. Contrary to this, vitamin E administration 6 mg/100 g of the diet increased the degree of fatty infiltration during the first 12 months. After 18 months a reverse effect appeared with inhibition of the progression of fatty infiltration. Thus the two-phase effect of vitamin E was a reverse of selenium effect. Addition of vitamin B15 to the diet (2.5 mg/100 g of diet) increased the degree of fatty infiltration of the liver which was maintained at a stable level throughout the whole experiment, i.e. 12-18 months.

Influence of lead poisoning on ultrastructural changes in the body wall of Eisenia foetida (Savigny), Oligochaeta. II. Long action of different concentration of lead on ultrastructural changes in the cells of the body wall.

The studies were performed on earthworms collected from March to September in the vicinity of Katowice. The earthworms were breed in Petri dishes on soil to which lead nitrate was added in the following concentrations 0.025, 0.10, 0.50 mg/g of soil. For the performed studies small specimen were taken from behind the citellum in which was lead histochemically evaluated. Tissue specimen taken from the citellum of the experimental animals were investigated in electronmicroscope. It has been found that lead accumulates in the sarcoplasm of the muscle fibres but not in the cell organells. Lead concentrations in the cells appear as regular crystals with membranaceous cover. The lead compounds used in the experiments does not provoke structural changes in the contractile elements of the muscle fibres, they induce only some deformations of mitochondria and hyperactivity of the glandular cells of the epithelium.

Zinc and lead interactions on alkaline phosphatase activity (E.C. 3.1.3.1.) in rats.

The interactions between zinc and lead in their effect on the biochemical and histochemical activity of alkaline phosphatase were investigated in different parts of the small intestine in rats: in the duodenum, jejunum and ileum, as well as in the liver, kidney and serum. The animals were divided into three experimental groups receiving during 120 days 50 micrograms/ml Zn, 100 micrograms/ml Pb and 50 micrograms/ml Zn + 100 micrograms/ml Pb in deionized water. In the duodenal mucosa in all experimental groups the activity of alkaline phosphatase was raised in relation to controls. The administration of both metals separately increased also the activity of the enzyme in the jejunal mucosa but their joint administration decreased this activity by 28% in relation to the control group. The activity of the enzyme in the ileal mucosa was decreased in all experimental animals. In the homogenates of the liver and kidneys of the rats given only zinc a statistically significant rise was found in the activity of the enzyme. In the remaining experimental groups this activity was decreased. Both metals given separately or jointly increased significantly the activity of the enzyme. Moreover, administration of lead caused a change in the location of alkaline phosphatase in the kidney shifting it towards the basement membrane of the epithelial cells in the convoluted tubules.

The effect of lead acetate on rat liver mitochondria.

The effect of two lead doses (100 and 200 micrograms Pb/kg) on the metabolism of rat liver mitochondria was studied determining the protein content of mitochondria and the activity of mitochondrial ATPase. Structural changes of mitochondria were studied in electron microscopy. Oxygen consumption was measured in mitochondria in two models: in vivo and in vitro. It was found that both doses used caused mitochondrial configuration changes in relation to control animals, reduced the amount of mitochondrial configuration changes in relation to control animals, reduced the amount of mitochondrial protein and the activity of mitochondrial ATPase and raised mitochondrial oxygen consumption in vivo and in vitro. The most powerful action of both lead consumption in vivo and in vitro. The most powerful during the first 30 minutes of lead contact with mitochondria. At the same time a significantly greater stimulation of mitochondrial respiration was observed after the lower dose of lead.

Influence of lead poisoning and ultrastructural changes in the body wall of Eisenia foetida (Savigny), Oligochaeta. I. Short action of different concentrations of lead and ultrastructural changes in the cells of the body wall.

The effect of short term influence of different concentrations of Pb(NO3)2 in the soil on the accumulation and localization of lead in the body wall cells of the earthworm Eisenia foetida (Savigny), Oligocheta, was studied histochemically. The experimental animals displayed the presence of lead deposits in the cytoplasm and vacuols of the epithelial gland cells which also showed morphological changes indicative of their increased secretory activity. Furthermore, a considerable accumulation of lead was found in the sarcoplasm and particularly in the sarcoplasmic reticulum of the muscle cells in the body wall. The histochemical data show that the most intense accumulation of lead is found in animals kept in an environment containing 0-05 mg Pb per 1 g of the soil. At this concentration of lead noteworthy morphological changes together with deposits of this metal are found in the mitochondria. This mitochondrial changes occurred together with the above mentioned, lead induced cytological deviations. They did not appear in other groups of experimental animals.

Accumulation and localization of lead in Eisenia foetida (Oligochaeta) tissues.

1. Accumulation and distribution of lead in tissues of Eisenia foetida (Oligochaeta) living in soils with different concentrations PbO2 was studied histochemically and with the use of the dithizione method. 2. The earthworms absorb lead from the soil through the alimentary canal as well as through the body wall. this leads to considerable accumulation of this metal in epithelial cells, especially in the epithelial gland cells of the body wall and of the alimentary tract. 3. High concentration of lead in the soil does not favour increased accumulation of lead in the earthworms' organisms. The histochemical data show that the most intense accumulation occurs when the concentration of PbO2 is 0-4 mg/1-00 g soil.