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[Aspartate and alanine aminotransferase activity in the liver and blood serum of protein-deficient rats receiving parenteral nitrogen nutrition].

The activity of aspartate and alanine aminotranspherase in the liver and blood serum was determined under parenteral nitrogen nutrition against a background of protein deficiency and protein inanition. The activity of these enzymes in the rat liver under conditions of protein deficiency and inanition is practically the same. The intraperitoneal administration of aminosol and amikin against a background of 10- and 20-day protein deficiency increases the activity of the enzymes under study in the liver. With protein deficiency and inanition the aspartate aminotranspherase activity in the liver under conditions of amikin per os feeding in the composition of protein-free semisynthetic food is considerably lower than under parenteral administration of this preparation respective dose. Under given condition of the experiment the alanine aminotranspherase activity in the liver is, vice versa, higher under per os feeding than under parenteral administration of amikin. It is also shown that administration of the parenteral nitrogen nutrition preparations containing only free amino acids (amikin) or a mixture of free amino acids and low-molecular peptides (aminosol) has a unidirected effect on reamination reactions adaptability in the liver.

Alanine Transaminase↗

Metabolism of lysosomal enzymes in the protein-deficient weanling rat.

We have shown that the protein-deficient weanling rat fed a 3% casein diet, within 2 to 4 wk, exhibits marked changes in serum lysosomal hydrolases similar to those observed in children suffering from protein-calorie malnutrition: serum hexosaminidase, alpha-mannosidase, and beta-glucuronidase activities increase 3-fold, 2-fold, and 50%, respectively, whereas the acid phosphatase levels decrease by 50%. Rehabilitation of the protein-deficient animals with a diet containing 25% protein (i.e., casein) results in a rapid restoration of the plasma lysosomal hydrolase profiles to normal in less than 1 wk. The specific activities of various tissue lysosomal enzymes change significantly in the protein-deficient animals; however, no overall consistent pattern of change is apparent. In general, the greatest number of changes in lysosomal enzymes occurs in the kidney, whereas the brain exhibits the smallest differences between experimental and control animals in this regard. Perfusion experiments have shown that the rate of release of lysosomal enzymes from livers of rats fed the protein-deficient diet is profoundly altered when compared to that of control animals. Studies of the variation of enzyme secretion with time have demonstrated that the rate of secretion of hexosaminidase by the liver remains low and then rises markedly (3-fold) after the animals have been consuming the 3% casein diet for 16 days. In contrast, the secretion of both acid phosphatase and beta-glucuronidase is markedly depressed in the early phase of protein malnutrition (i.e., 7 to 16 days), and then increases greatly by the 3rd wk. These results demonstrate that changes occur in the rate of secretion of lysosomal enzymes by the liver during the course of experimental protein malnutrition.

Acid Phosphatase↗

Morphometric analysis of the myelin-associated oligodendrocytic basic protein-deficient mouse reveals a possible role for myelin-associated oligodendrocytic basic protein in regulating axonal diameter.

Myelin-associated oligodendrocytic basic protein is a member of the proteins constituting the central nervous system myelin. By morphometric analysis, we demonstrated that axons of myelin-associated oligodendrocytic basic protein-deficient mice had larger diameters and more myelin lamellae as compared to those of wild-type mice at the same age. It is known that the number of myelin lamellae increases linearly with axonal diameter, and that the rate of radial axonal growth is the factor controlling the rate of myelin formation. In line with these observations, we found that the regression line for axonal diameter and the number of myelin lamellae in myelin-associated oligodendrocytic basic protein-deficient mice appeared to be identical to that in wild-type mice, indicating that the increase in the number of myelin lamellae was the result of the increase in axonal diameter. Furthermore, we generated myelin basic protein/myelin-associated oligodendrocytic basic protein-double-deficient mice through mating myelin-associated oligodendrocytic basic protein-deficient mice with shiverer mice, an autosomal recessive mutant characterized by a lack of all isoforms of myelin basic protein. With these knock-out mice, we showed that axons of the double-deficient mice had larger diameters and smaller form factor, an index of the deformation of the fiber contour, in ensheathed fibers than those of shiverer mice, although there was no difference in axonal diameter of unmyelinated fibers between them. Taken together, myelin-associated oligodendrocytic basic protein seemed to play a role in controlling axonal diameter and in keeping axons round.

Animals↗

Effects of protein deficiency on the biosynthesis and degradation of ribosomal RNA in rat liver.

Employing livers from rats fed on a protein-free diet for two weeks, the effects of protein deficiency on both biosynthesis and degradation of rRNA were investigated and the following results were obtained. 1. Protein deficiency led to a decrease of total liver RNA content per DNA to about 80% of that in normal rat liver. 2. From the kinetics of rRNA labelling with [14C]orotic acid in vivo, the half-lives of cytoplasmic rRNA's of normal and protein-deficient rat livers were determined to be 6.2 and 5.1 days, respectively. Furthermore, considering the pool size of rRNA in rat liver, the turnover rate of cytoplasmic rRNA was calculated to be 0.212 pmole/min/mg of nuclear DNA in normal rats and 0.240 pmole/min/mg of nuclear DNA in protein-deficient rats. 3. From the electrophoretic patterns of nucleolar RNA's of both groups of rat livers labeled with [14C]orotic acid, the time courses of the specific activities of nucleolar 45S, 32S, and 28S rRNA's were analysed and the half-life of each nucleolar RNA in both groups of rat livers was determined. Nucleolar 45S, 32S, and 28S RNA's had half-lives of 6.0, 15.9, and 26.5 min in normal rats, respectively, and 5.5, 19.4, and 22.9 min in protein-deficient rats, respectively Considering the pool size of each nucleolar RNA obtained from the leectrophoretic pattern, the turnover rates of 45S, 32S, and 28S RNA's were calculated to be the same, i.e., o.189 pmoles/min/mg of nuclear DNA, in normal rat liver and 0.372, 0.372, and 0.358 pmoles/min/mg of nuclear DNA in protein-deficient rat liver, respectively. 4. These results indicate that protein deficiency increased both the rate of degradation of cytoplasmic rRNA and that of nucleolar rRNA synthesis in rat liver. While in normal rat liver the rates of rRNA synthesis and degradation were rather similar, the rate of rRNA synthesis in protein-deficient rats was about 1.5 times higher than that of its degradation. Therefore, the decrease of total liver RNA content in protein deficiency might be accounted for by stimulated degradation of rRNA in the nucleus. 5. The activities of RNase in nuclear fractions of both groups of rat livers were compared. Both activities of nuclear acid RNase and especially that of the free form of alkaline RNase in protein-deficient rat liver were higher than those in normal rat liver.

Animals↗

Suppression of rejection of Nippostrongylus brasiliensis in iron and protein deficient rats: effect of syngeneic lymphocyte transfer.

Rejection of Nippostrongylus brasiliensis is impaired in iron and protein deficient rats and this suggests that iron and protein deficiency directly or indirectly suppresses the immune response. The site of the immunological defect in deficient rats was investigated using the technique of cellular transfer of resistance. The functional activity of immune mesenteric lymph node cells obtained from iron and protein deficient donors was not depressed as measured by their capacity to cause parasite rejection in nutritionally sufficient recipients. In contrast, immune lymph node cells obtained from either sufficient or deficient donors did not result in parasite rejection in iron and protein deficient recipients. These results indicate that there is no permanent defect of lymphocyte function in iron and protein deficient rats and suggest that either some other component of the rejection mechanism is defective, or that lymphocyte function is blocked in an iron and protein deficient environment.

Animals↗

Influence of protein deficiency in rats on hormonal status and cytoplasmic glucocorticoid receptors in maternal and fetal tissues.

The influence of dietary protein deficiency on maternal plasma corticosterone and progesterone levels as well as on maternal and fetal liver and lung cytoplasmic glucocorticoid receptors has been studied in Sprague-Dawley rats during the last 3 days of gestation. Plasma corticosterone levels of control but not protein-deficient rats increased on days 20 and 21 of gestation; corticosterone levels of protein-deficient rats decreased on day 21 of gestation. Maternal adrenalectomy caused only a moderate decrease in corticosterone levels in both groups of pregnant rats. Fetal corticosterone levels of the two groups of rats were similar. Progesterone levels were consistently lower in protein-deficient than in control animals from day 20 of gestation until 2-12 h after parturition. There were no differences in the binding of [3H]dexamethasone to liver cytosol of non-pregnant control and protein-deficient rats. However, receptor levels were lower in pregnant controls than in pregnant protein-deficient rats. Maternal protein deficiency led to an increase in fetal liver glucocorticoid receptor levels but exerted no significant effect on receptor levels in fetal lung. It is suggested that lower levels of plasma corticosterone and progesterone and high levels of liver glucocorticoid receptors in protein-deficient rats might be related to some of the adverse consequences of maternal malnutrition on fetal development.

Animals↗

Both ethanol and protein deficiency increase messenger RNA levels for pancreatic lithostathine.

Both ethanol abuse and protein deficiency are well known associations of chronic pancreatitis. An early event in chronic pancreatitis is the deposition of protein plugs in small pancreatic ducts, leading to ductular obstruction and acinar cell damage. Lithostathine, a pancreatic secretory protein, is a major organic component of protein plugs. The aim of this study was to determine the effect of chronic ethanol administration and dietary protein deficiency, separately and in combination, on messenger RNA (mRNA) levels for pancreatic lithostathine. Male Sprague-Dawley rats were fed in groups of four, for four weeks, protein sufficient and protein deficient diets with or without ethanol. Messenger RNA levels for pancreatic lithostathine were assessed in all four groups. Both ethanol and protein deficiency, separately and in combination, increased mRNA levels for lithostathine. Thus, both chronic ethanol consumption and dietary protein deficiency increase the capacity of the pancreatic acinar cell to synthesize lithostathine.

Alcoholism↗

Protein deficiency impairs erythropoiesis in rats by reducing serum erythropoietin concentration and the population size of erythroid precursor cells.

Erythropoietin (EPO), a glycoprotein produced mainly by the kidney, is the major physiological regulator of erythropoiesis. We developed a sensitive and rapid ELISA for measurement of rat serum EPO with two monoclonal antibodies that recognize different epitopes. To understand the mechanism by which erythropoiesis is impaired in rats deficient in dietary protein, we investigated the levels of the immunoreactive EPO (iEPO) in serums and erythroid precursor cells in hemopoietic tissues during protein deprivation. The iEPO level of 32-d-old rats fed a protein-free diet was lowered to one-third that of rats fed 20% casein at 6 h after protein deprivation began. Protein deprivation decreased the number of EPO-responsive cells in spleen. These results indicate that the impairment of erythropoiesis during protein deficiency is caused by the decrease in serum EPO and the subsequent reduction of the population size of erythroid precursor cells in spleen.

Animals↗

The phospholipid-dependence of uridine diphosphate glucuronyltransferase. Effect of protein deficiency on the phospholipid composition and enzyme activity of rat liver microsomal fraction.

After force-feeding a protein-free diet to male rats for 5-7 days a substantial (2.4-fold) increase in the specific activity of the liver microsomal enzyme UDP-glucuronyltransferase (EC 2.4.1.17) was observed. A similar activation of the enzyme occurred when rats were fed on a low-protein (5%, w/w, casein) diet for 60 days. Although both the short- and long-term protein-deficient diets decreased the contents of microsomal protein and phospholipid in liver tissue they did not significantly alter the ratio of these major membrane components. Protein deficiency profoundly altered the phospholipid composition of microsomal membranes. The most striking difference in microsomal phospholipid composition between control and protein-deficient rats was their content of lysophosphatides. Whereas microsomal membranes from protein-deficient rats contained significant proportions of lysophosphatidylcholine and lysophosphatidylethanolamine very little or no lysophosphatides were detected in control preparations. Pretreatment of microsomal fractions from normal rats with phospholipase A markedly increased their UDP-glucuronyltransferase activity as did their pretreatment with lysophosphatidylcholine. It is concluded that the quantities of lysophosphatides present in microsomal membranes from protein-deficient rats were sufficient to have caused the increased UDP-glucuronyltransferase activities of these preparations. Evidence is presented suggesting that these changes in microsomal phospholipid composition and UDP-glucuronyltransferase activity caused by protein deficiency reflect changes that occur in vivo. The possible physiological significance of these findings is discussed.

Acute Disease↗

Effects of severe energy and protein deficiencies on the fibres and nuclei in skeletal muscle of pigs.

1. Measurements have been made of the size and number of muscle fibres and number of nuclei in a small indicator muscle (m. flexor digiti V brevis) in the fore-foot of the pig. Well-nourished, 10-d-old and 1-year-old animals were studied, as well as 1- and 2-year-old animals that were severely energy-deficient and protein-deficient. 2. The normal 1-year-old animals had much larger muscle fibres, with more nuclei, than the pigs in any of the other groups. 3. There were no significant differences between the numbers of fibres in the muscles of pigs in any of the four groups. 4. There was a significant difference between the number of fibres in the muscles of pigs coming from different litters, irrespective of their dietary history after birth. This suggests that the number of fibres is determined genetically before birth, and all that can take place after birth is an alteration in size.

Age Factors↗

The effects of dietary protein deficiency on rat testicular function.

Diets containing 0%, 5% and 10% protein were used for treatment periods of 30, 50, and 90 days respectively. Control rats were fed a diet containing 20% protein. Protein deficient rats failed to gain weight during the experiment. In addition, the weights of the testis, epididymis, prostate and seminal vesicle also decreased, with the 10% group less affected than the 0% and 5% groups. Testicular histology indicated retarded germ cell maturation in the 0% and 5% groups only. Overall testicular cell number and size were reduced in treated rats and there was a reduction in the diameter of the seminiferous tubule in these groups. Epididymal epithelial height was also reduced in protein deficient rats with a concomitant increase in the number of epididymal duct cross sections devoid of sperm. Protein deficiency caused significant reductions in testicular DNA, RNA and protein content. The proportion of motile epididymal sperm decreased in the 0% and 5% groups by 90% and 35% respectively. Epididymal sperm number decreased in both the 0% and 5% groups by 90% while the proportion of abnormal sperm increased by 65% and 61% respectively. Circulating androgen levels were also lowered by more than 50% on average in protein deficient animals.

Androgens↗

Fruits, vegetables, and hMLH1 protein-deficient and -proficient colon cancer: The Netherlands cohort study.

BACKGROUND: Clinical and pathologic differences exist between colon carcinomas deficient and proficient in the mismatch repair protein hMLH1. Animal and in vitro studies suggest that fruits, vegetables, folate, and antioxidants are associated with colonic expression of mismatch repair genes. METHODS: Associations between consumption of fruits and vegetables and hMLH1 protein-deficient and -proficient colon cancer were evaluated in the Netherlands Cohort Study on diet and cancer using a case-cohort approach. A self-administered food frequency questionnaire was completed, in 1986, by 120,852 individuals ages 55 to 69 years. Using immunohistochemistry, hMLH1 protein expression was assessed in colon cancer tissue obtained from 441 patients who were identified over 7.3 years of follow-up excluding the initial 2.3 years. Incidence rate ratios (RR) were estimated for hMLH1 protein-deficient and -proficient colon cancer. RESULTS: hMLH1 protein expression was absent in 54 tumors (12.2%) and present in 387 tumors. Fruit consumption was associated with hMLH1 protein-deficient colon cancer [highest versus lowest tertile, RR, 0.46; 95% confidence interval (95% CI), 0.23-0.90; P(trend) = 0.029] but not with hMLH1 protein-proficient tumors (highest versus lowest tertile, RR, 1.03; 95% CI, 0.78-1.35; P(trend) = 0.81). Total consumption of vegetables was not associated with either type of tumor (hMLH1 protein deficient: RR, 0.86; 95% CI, 0.45-1.65; P(trend) = 0.67; hMLH1 protein proficient: RR, 0.94; 95% CI, 0.72-1.23; P(trend) = 0.72). No associations were observed for folate, fiber, antioxidants, or subgroups of vegetables. CONCLUSION: These analyses indicate that an inverse association between consumption of fruits and colon cancer may be confined to the subgroup of tumors with a deficient mismatch repair system.

Adaptor Proteins, Signal Transducing↗

Pituitary-testicular function in protein-deficient rats. Follicle-stimulating hormone hyperresponse to castration and supersensitivity of gonadotropin secretion to androgen negative feedback.

Previous studies have shown that weanling male rats fed a low protein diet ad libitum develop hypogonadotropic hypogonadism. Two unusual features of this state were 1) subnormal serum FSH in noncastrate rats but not in castrate rats, suggesting that FSH was being suppressed by a testicular factor, and 2) serum FSH increases after castration that were greater in protein-deficient rats than in controls. In the current study, protein-deficient rats showed FSH hyperresponse to castration, compared to either ad libitum or pair-fed controls, after periods of low protein feeding from 1-8 weeks and periods of castration from 1-8 weeks. FSH hyperresponse to castration was rapidly induced after the start of low protein feeding and was present whether castration was performed before or after low protein feeding was begun. In none of these circumstances did protein-deficient rats show LH hyperresponse to castration. Inhibin production of Sertoli cell cultures prepared from protein-deficient rats was less (P less than 0.02) than in ad libitum or pair-fed controls, suggesting that inhibin overproduction was not the cause of subnormal serum FSH in noncastrate protein-deficient rats. However, castrated rats fed a low protein diet were more sensitive to the negative feedback effects of testosterone on gonadotropin secretion than were ad libitum or pair-fed controls. We conclude that low serum gonadotropins in protein-deficient male rats may be related to hypersensitivity of these animals to the negative feedback effects of testosterone on gonadotropin secretion. In addition, FSH hyperresponse to castration, without corresponding LH hyperresponse, seems to be typical of protein deficiency, suggesting that protein deficiency may be a useful model for exploring the differential control of gonadotropin secretion.

Animals↗

Free protein S levels are elevated in familial C4b-binding protein deficiency.

In plasma, 40% of the protein S is free and functions as a cofactor for the anticoagulant effects of activated protein C. The remaining 60% of protein S is complexed to C4b-binding protein and is functionally inactive. A family with hereditary C4b binding protein deficiency has been identified with C4b-binding protein levels in an affected father and daughter of 37 micrograms/mL and 23 micrograms/mL, respectively; these values are significantly below the normal range for this protein of 180 micrograms/mL +/- 44 micrograms/mL (mean +/- 2 SD). The total protein S (free + bound) is normal in these individuals (23.2 micrograms/mL and 17.8 micrograms/mL, respectively; normal 19.1 micrograms/mL +/- 6.0 micrograms/mL). The free protein S levels are markedly increased at 22.5 micrograms/mL and 17.4 micrograms/mL, respectively (normal 5.9 micrograms/mL +/- 2.4 micrograms/mL). This experiment of nature shows that total protein S levels in plasma are not affected by the absence of C4b-binding protein and that chronic elevation of free protein S is not associated with increased hemorrhagic tendencies.

Adult↗

Biokinetics of 65Zn in liver and whole body and its bio-distribution in nickel treated protein deficient rats.

This study was designed to determine the effect of nickel treatment on biological half-lives of 65Zn in whole body and liver as well as on distribution of 65Zn in different organs of protein deficient rats. Nickel sulfate at a dose level of 800mg/l in drinking water was administrated to normal control as well as to protein deficient rats for 8 weeks. A significant increase was found in fast and slow components of biological half lives of 65Zn in whole body and only fast component in liver of protein deficient rats. Interestingly, slow component in whole body and fast component in liver of nickel treated protein deficient rats were not different from normal controls though they were significantly elevated in protein deficient rats. On the other hand, slow component of 65Zn was also not altered in nickel treated protein deficient rats, which however, was significantly decreased in nickel treated rats. Protein deficiency led to a marked elevation in per cent uptake of 65Zn in brain and caused significant depression in liver, kidney and intestine. However, uptake of 65Zn in brain showed a significant depression in nickel treated rats, whereas the uptake was elevated in brain in nickel treated protein deficient rats. In conclusion, protein deficient conditions seem to be playing a dominant role in context with the distribution of 65Zn in different organs when nickel is administered to protein deficient rats. However nickel alone is seen to cause adverse effect on the distribution of 65Zn.

Animals↗

Effect of gossypol on rats maintained on protein deficient and low potassium diets.

Sexually mature male albino rats were divided into four groups of 5 animals each. Animals of group I served as control, whereas animals of group II received gossypol (20 mg/kg body weight/day) for 45 days. Animals of groups III and IV were maintained on protein deficient diet. Animals of group IV received 20 mg/kg gossypol in addition to the protein deficient diet. Animals of group III and IV received protein deficient diet for 45 days before initiating gossypol treatment. The total period of maintaining the animals on protein deficient diet was 90 days. In another experiment, the same experimental protocol was followed except that the animals were maintained on low potassium diet instead of protein deficient diet. A significant decrease in body weight of animals was observed following protein deficient and gossypol (group IV) treatment. Testis weight decreased significantly in the animals of group III (protein deficient) and group IV (protein deficient + gossypol). Similar observations were made in the animals maintained on low potassium diet. In both the experiments, sperm motility was reduced significantly. Histologically, in the testis of animals of group IV (protein deficient + gossypol) almost all the tubules were disorganised and vacuolated and total arrest of spermatogenesis could be observed in majority of the tubules.

Animals↗

Effect of protein deficiency on endogenous pyrogen-mediated acute phase protein responses.

Endogenous pyrogen (EP) is known to trigger a rise in the plasma concentrations of various acute phase reactant proteins. This study describes the effects of chronic protein deficiency in rabbits on EP-mediated changes in the plasma concentrations of fibrinogen, albumin, and alpha 2-macroglobulin. Injection (i.v.) of EP from healthy donors into protein-deprived rabbits produced a smaller rise in plasma fibrinogen and alpha 2-macroglobulin, and a smaller fall in plasma albumin than injection of EP into controls. Injection of EP, obtained from malnourished donors, into healthy rabbits also resulted in an attenuation of the acute phase protein response. These data are consistent with the hypothesis that EP activity is influenced by the nutritional status of both the donor and recipient of EP.

Animals↗

Protein deficiency in carbon tetrachloride-induced hepatic lesions.

The influence of protein deficiency on the hepatotoxicity of carbon tetrachloride (CCl4) was investigated in a group of rhesus monkeys. Animals fed a protein-rich diet served as controls. The results indicate that protein-deficiency protects the liver against acute hepatotoxicity of this drug. The protective effect is abolished if the animals are administered phenobarbital prior to the administration of CCl4. The protective action is due to a reduction, in protein deficiency, of the endoplasmic reticulum associated enzymes involved in hepatotoxicity of CCl4. Repeated administration of CCl4, which induces hepatic regeneration, resulted in disappearance of fat from periportal cells in protein-deficient animals. The regenerating cells (because of their better enzyme system) acquire "nutritional autonomy" and are thus able to synthesize adequate amounts of lipoproteins for mobilization of liver triglycerides.

Animals↗