Iodine, carbohydrate and protein metabolism in rats receiving insufficient amount of iodine in the feed

Significant changes in the iodine, carbohydrate and protein metabolism are observed under conditions of prolonged iodine deficiency in the rat ration. The reason-consequent correlations between the main links of iodine metabolism are shown. Indices of protein and carbohydrate metabolism are stated to depend on the concentration of protein-bound iodine in blood.     

Age-related changes in the tissue content of total iodine, its hormonal and nonhormonal compounds and their metabolic course

By the spectrophotometric method the age changes of total iodine content, its hormonal and non-hormonal compounds in rats and men tissues (muscles, liver, kidney, heart, lungs, brain, spleen and blood) have been studied. It was established that the total iodine content decreased at the expense of the protein-bound iodine concentration and also of the butyl-alcohol extractable iodine. The exchange of thyroid hormones intensity lowered.     

Metabolic effects of high doses of manganese in rats

The effects of acute manganese (Mn) toxicity on tissue manganese concentrations and on plasma glucose levels were investigated in adult male Sprague-Dawley rats. Manganese injection in all tissues analyzed was reflected by a significant increase in Mn concentration that was transitory. Changes in the molecular localization of Mn in liver following injection include both increases in protein-bound Mn and low molecular weight Mn complexes. A rapid, dose-responsive rise in blood glucose followed Mn injection, whereas circulating insulin levels decreased after injection. These data show that acute changes in tissue Mn levels can have a pronounced effect on carbohydrate metabolism.     

Cobalt resistance in Neurospora crassa: overproduction of a cobaltoprotein in a resistant strain

A cobalt-resistant strain of Neurospora crassa (cor) is 20-fold more resistant to Co when compared with the wild type. DEAE-cellulose and metal-chelate affinity chromatography of cell-free extracts separated cobalt into protein-bound and free ionic fractions. In N. crassa cor about 80% cobalt of cell-free extracts was protein bound while the same in wild type was only 25%. Cobalt content of the protein-bound fraction increased with time and cobalt concentration in the growth medium, and was not influenced by related metal ions. A cobaltoprotein (CBP) which is overproduced in N. crassa cor and constitutes up to 12% of total protein of extracts was purified. CPB is a brown coloured (absorption peaks at 275, 350 and 440nm), small molecular weight glycoprotein (Mr 8200 daltons) with 28 - 30% carbohydrate (mannose). CBP has 70 g cobalt mg-1 protein. Cysteine, glycine, glutamic acid and aspartic acid are the major amino acid constituents. The role of CBP in cobalt resistance is discussed in relation to other known metalloproteins involved in resistance. © Rapid Science 1998.     

The effects of cobalt and iodine supplementation of the pregnant ewe diet on immunoglobulin G, vitamin E, T3 and T4 levels in the progeny

Sixty twin-bearing ewes were allocated to one of four dietary treatments investigating the effects of supplementary iodine or cobalt during late pregnancy on lamb serum immunoglobulin G (IgG), triiodothyronine (T3), thyroxine (T4) and vitamin E concentrations, and lamb IgG absorption efficiency. Ewes were offered grass silage ad libitum supplemented with 800 g per ewe per day of a 190 g/kg crude protein (CP) concentrate from day 126 of gestation until parturition plus one of the following supplements (n = 15 per treatment); no supplement (C); 26.6 mg iodine per day for final 3 weeks pre partum (I-3); 26.6 mg iodine/day for final week pre partum (I-1); 20 mg cobalt/day for final 3 weeks pre partum (Co-3). Lambs were blood sampled at 24 and 72 h post partum for serum IgG and vitamin E concentrations. Ten lambs from C and I-3 were blood sampled at 1 h post partum for serum IgG, vitamin E, T3 and T4 concentrations. There were no differences in serum IgG, vitamin E or T4 values (P > 0.05) at 1 h post partum between lambs born to the C and I-3 ewes. T3 levels were lower in I-3 compared with C progeny (P < 0.05). Supplemental iodine reduced colostral IgG absorption efficiency (P < 0.001) and lamb serum IgG concentrations at 24 and 72 h post partum (P < 0.001). Serum vitamin E concentration in I-3 and I-1 lambs was lower than in Co-3 lambs at 24 h post partum, while at 72 h post partum I-3, I-1 and Co-3 lambs had significantly lower concentrations than C lambs (P < 0.001). Supplementing the ewe's diet with 26.6 mg/day of iodine for the final week of pregnancy reduced lamb serum IgG concentration at 24 and 72 h post partum. The lower total and free T3 values in the progeny of I-3-treated ewes suggest interference in the synthesis and metabolism of thyroid hormones when ewes receive excessive dietary iodine for 3 weeks immediately pre partum. Based on these findings, the indications are that the toxicity level for iodine in the diet of the pregnant ewe should be lowered to 20 mg per ewe per day, equivalent to 40% of its current level. The finding that high-level cobalt supplementation during the final 3 weeks of pregnancy will have a negative effect on serum vitamin E concentration at 72 h post partum is a new and significant finding and previously has not been reported in the literature.     

Perchloric acid-soluble proteins and protein-bound hexoses in serum and tissues of normal, hypo-and hyperthyroid rats.

The total content of perchloric acid-soluble proteins (PCA-SP) and protein-bound hexoses (PBH) were studied in blood serum and tissues (liver, kidney, lung, brain) of normal, hypo- and hyperthyroid rats. The results obtained indicate that the hyperthyroid state induced an increase in both PCA-SP and PBH in blood serum and studied tissue homogenates, and hypothyreosis causes a decrease of total glycoproteins content in all studied materials. The results were counted per 1 g of protein and in this way the nonspecific effect of thyroid hormones on the protein metabolism had no influence on the measurements.     

Thyroid homeostasis in animals with iodine deficiency

The content of total iodine, its hormonal and nonhormonal fractions as well the level of protein-bound iodine in blood and basic tissue targets in representatives of 4 classes of animals: Esox lucius L., Rana esculenta, Streptopelia decaocto Priv., Lepus europaeus Pall. inhabiting the mountain regions with iodine deficiency in environment and in the lowlands of Transcarpathia with higher iodine provision have been investigated. A considerable decrease of general and hormone iodine level in the animal tissues of the mountain area accompanied by the suppression of the thyroid function has been stated. The utilization of thyroid hormones under the iodine deficiency condition is increased in the majority of cases and the level of protein-bound iodine is lowered that testifies to the transition of animal organism in the iodine-deficient areas to the lower level of thyroid homeostasis.     

Carbohydrate and nitrogenous metabolism condition in the rat tissue under experimental rhabdomyolysis

Some effects of glycerol injection on indices of the condition of the thiol-disulfide system as well as carbohydrate and nitrogen metabolism in rats in vivo were studied. A decrease was revealed in levels of non-protein SH-groups in the liver, kidney and heart, as well as of protein SH-groups in the kidney and heart of rats following glycerol injection. That might be connected with SH-group oxidation under the excessive arrival of free haem into tissues under rhabdomyolysis. A decrease in glycogen and increase in tyrosine aminotransferase activity in the liver were observed. Activation of nitrogenous metabolism following glycerol injection is indicated by the increase of aminotransferase activity in organs, and concentration of blood urea. High concentration of creatinine in the rat serum can reflect malfiltration in kidneys.     

Blood and urine iodine levels in patients with gastric cancer

In this study, we aimed to investigate whether there is any relationship between gastric cancer and iodine concentrations in blood and urine in the northeast Anatolia region, where iodine deficiency is common. A total of 56 patients, diagnosed as gastric cancer and 25 healthy volunteers were included in the study. The methods used were based on the Sandell-Kolthoff reaction. The urine iodine concentration (UIC) and serum protein-bound iodine (PBI) levels were higher in patients with gastric cancer compared with healthy control subjects. The UIC in stage IV was higher than all other stages and the control group. The UIC was higher in stages III and IV compared with stages I and II. However, serum PBI levels in stage III were higher compared with stages I, and II and also control group. The serum PBI level in stage IV was higher than stage II and the control group. In the patient and control groups, there were no significant differences in serum PBI and UIC with regard to age or sex. Our results suggested that urinary and blood iodine concentration might be a useful marker for following the disease.     

Placental transport and utilization of amino acids and carbohydrates

Uteroplacental tissues have been shown to have a high rate of metabolism under in vivo steady-state conditions. Fully two-thirds of the glucose and one-half of the oxygen consumed by the uterus are utilized by these tissues rather than by the fetus. Its high metabolic rate must be borne in mind in any analysis of tracer kinetics, which prohibits the exclusion of these tissues and the use of a two-compartment model for analysis of carbohydrate and amino acid metabolism. Current techniques permit determination of utilization rates of nutrients in all three compartments (fetal, uteroplacental, and maternal) with considerable precision. Using tracer amino acids one can determine rates of protein synthesis and protein breakdown as well as rates of amino acid oxidation. These techniques should prove useful in investigating the role of various trophic factors in fetal life and in assessing the impact of changes in placental function or maternal nutritional state on fetal growth and metabolism.     

Checking of some hypotheses of the pathogenesis of diabetes mellitus by mathematical modeling

A mathematical model of normal regulation of carbohydrate metabolism by the pancreas endocrine apparatus is presented. In a numerical experiment the model imitated changed levels of sucrose, insulin glucagon and gastrointestinal hormones in the blood in response to the ingested 50 g of glucose. The model of normal regulation was damaged in the way which theoretically should result in diabetes development. Then an estimation was made to what extent the disturbances of carbohydrate metabolism characteristic of diabetes were reproduced by the changed model. It has been shown that disturbances specific for diabetes appear when the sensitivity of beta-cells to glucose stimulus or hyperproduction of glucagon decreased. No changes in the behaviour of blood glucose typical of diabetes were obtained in the model when a decrease of the sensitivity of insulin receptors due to hyperinsulinemia in insulin-dependent tissues was imitated, as well as an increased activity of liver insulinase or hyposecretion of gastrointestinal hormones. These results point to the necessity of further development of these hypotheses.     

Effect of gibberellin on protein and non-structural carbohydrate in dormant Avena fatua caryopses

Application of gibberellic acid (GA₃) to dormant Avena fatua L. caryopses resulted in the termination of dormancy within 24 h as indicated by germination between 24 and 48 h. During the period of imbibition from 0 to 24 and 24 to 48 h changes occurred in protein and carbohydrate metabolism in GA-treated and untreated caryopses. Germination did not occur in untreated caryopses, therefore physiological changes in these caryopses were not associated with the termination of dormancy. GA-treatment increased the concentration of soluble and SDS-extractable protein in the endosperm tissue by 4 and 5%, respectively, over the 24 h untreated material; no changes were apparent when the protein profiles of GA-treated and untreated tissues were compared by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) 0, 24 and 48 h after imbibition. The concentration of hexose and sucrose in the GA-treated endosperm tissue increased 189 and 151 μmol, respectively, over the untreated material at 24 h. Gibberellic acid had no effect on starch metabolism in the endosperm tissue in the first 24 h, the period associated with the termination of dormancy. The concentration of hexose increased by 57 μmol and starch decreased by 80 μmol in the GA-treated embryo tissue within 24 h. Our results demonstrate that exogenously applied GA influences sucrose and hexose metabolism in the endosperm tissue. The specific effect of GA on starch and hexose metabolism in the dormant A. fatua caryopsis embryo tissue may be associated with the termination of dormancy.     

The Effect of Povidone-Iodine (Betadine) on Serum Protein-Bound Iodine,When Used as a Surgical Preparation on Intact Skin

A study was undertaken to determine whether the use of povidone-iodine (Betadine) as a skin disinfectant prior to surgery would affect the protein-bound iodine (PBI) and so invalidate this parameter of thyroid function.Ninety-seven consecutive patients were chosen who had no thyroid disease and who had not recently been exposed to iodine in any form. Their serum PBI levels were determined before and after a wide variety of surgical operations. Povidone-iodine was used as a skin disinfectant in the operating room in all cases. Care was taken to avoid contact of the povidone-iodine with the mucous membranes.No significant change in the protein-bound iodine could be detected and it was concluded that there could be no objection to the use of povidone-iodine on the ground of its possible effect on the protein-bound iodine.     

Effect of chronic effect of the electrostatic field on various biochemical indicators of the tissues

The action of electrostatic field (320 kV/m) on the adaptability has been studied in experiments on young Wistar rats (females). Some parameters of carbohydrate, lipid and protein metabolism, and the process of lipid peroxidation were observed in blood serum, liver and brain. Glucose content was observed to increase in all the tissues, liver glycogen, cholesterol/phospholipid ratio. The urea and malondialdehyde increased in the liver and brain. The experiments have shown that the physiological adaptability is high.     

Investigation of total, free, peptide-bound, protein-bound, soluble and insoluble collagen hydroxyproline content in tissues from the Arabian camel (Camelus dromedarius)

This study was conducted to determine the concentration of total, free, peptide-bound, protein-bound, soluble and insoluble collagen hydroxyproline (Hyp) in tissues from the Arabian camel (Camelus dromedarius). Results indicated that there were significant differences in the concentration of total, free, peptide-bound, protein-bound, soluble and insoluble collagen Hyp in various tissues (P < 0.01). Camel kidney showed a significantly high concentration of total, free, peptide-bound and protein-bound Hyp and collagen content as compared to other tissues examined (P < 0.01). Kidney also showed a significantly high concentration of soluble collagen Hyp as compared to other tissues examined (P < 0.01). However, the concentration of insoluble collagen Hyp was significantly high in liver when compared to other tissues (P < 0.01). These variations may result from differences in the collagen structure and/or composition in this species.     

Occurrence of tyrosine sulfate in proteins--a balance sheet. 1. Secretory and lysosomal proteins

1. The abundance of tyrosine sulfate in secretory proteins and in various classes of cellular proteins has been quantified and compared to protein-bound carbohydrate sulfate. 2. HepG2 cells and fibroblasts, two cell types showing only the constitutive pathway of secretion, and PC12 cells, which show both the constitutive and the regulated pathway of secretion, were subjected to pulse-chase and/or long-term labelling with [35S]sulfate and [3H]tyrosine, followed by analysis of proteins in the cells and medium. Under both conditions of labelling, 65-92% of the protein-bound tyrosine sulfate and 44-84% of the protein-bound carbohydrate sulfate were found to be secretory. In HepG2 cells, the frequency of sulfation of tyrosine residues, which can be determined independently from protein abundance and the rate of protein synthesis, was 8-22 times higher in proteins secreted into the medium than in cellular proteins. 3. All cell lines studied contained significant amounts, not only of carbohydrate sulfate, but also of tyrosine sulfate in specific cellular proteins. As shown for fibroblasts, these tyrosine-sulfated proteins were retained within the cells for at least 100 min of chase following a pulse with [35S]sulfate and were almost completely recovered in a light membrane fraction after subcellular fractionation. 4. Lysosomes were found to contain small, but significant, amounts of protein-bound tyrosine sulfate in addition to protein-bound carbohydrate sulfate. Protein-bound tyrosine sulfate in lysosomes reached a peak at 20 min of chase and rapidly disappeared thereafter, whereas protein-bound carbohydrate sulfate accumulated after 20 min of chase. Examination of the known sequences of eleven lysosomal enzymes revealed the presence of potential tyrosine sulfation sites in five of them. 5. Our results show that secretory proteins are the most abundant, but not exclusive, in vivo substrates for tyrosine sulfation and suggest the presence of soluble tyrosine-sulfated proteins in lysosomes and other, as yet unidentified, organelles of the secretory pathway. In the following paper in this journal we describe the abundance of tyrosine sulfate in integral membrane proteins.     

Effects of Y. pestis mouse toxin on carbohydrate metabolism in rats

Effects of intravenous Y. pestis mouse toxin (LD50) injection on glucose, lactate glucagon, insulin blood levels and cAMP liver content in dynamics of intoxication development were studied. Hypoglycemia, observed 2 hours after toxin administration seems not to be due to the enhanced glucose utilization in peripheral tissues because insulin blood level during this period was decreased and lactate concentration has not been changed. Glucagon content by 2-5 hour of shock was strong elevated. Proposal is made that Y. pestis mouse toxin might induce carbohydrate metabolism alterations via direct liver glucose synthesising enzymes inhibition rather than cAMP-dependent glycogenolysis and gluconeogenesis regulation disturbances in this organ.     

Mass-transfer based modeling to investigate iodine staining effects for enhanced contrast X-ray computed tomography

Iodine staining combined with X-ray computed tomography (CT) has become a core approach in anatomy, offering three-dimensional and essentially non-destructive imaging of soft tissues. Although there have been rapid advances in methodologies and techniques, the mechanisms underlying diffusible iodine contrast-enhanced CT are not yet fully understood. The protocols for staining samples of differing sizes and tissue types have not yet been justified theoretically. Here we utilize mass transfer modeling to simulate iodine diffusion and predict iodine concentrations within distinct tissue types. We also undertake iodine staining experiments to visualize the detailed anatomy and contrast effects on whole-body avian specimens using different concentrations of iodine solution to compare with model simulation results. The simulations effectively explain most observed concentration changes in differently-sized samples over distinct iodine treatment durations. These results also provide insight into the mechanisms behind the efficacy of solution replenishment for enhancing staining effects. Both consistencies and inconsistencies between our simulation and experimental results regarding iodine concentration in tissues will inform further investigations to optimize iodine staining protocols.     

The effects of mefenamic acid on postprandial intestinal carbohydrate metabolism

The effects of mefenamic acid on the food-induced changes in intestinal carbohydrate metabolism were determined in an attempt to elucidate the mechanism(s) by which inhibition of prostaglandin synthesis enhances the postprandial increases in intestinal blood flow and oxygen consumption. The data show that when the luminal perfusate was changed from saline to a nutrient/bile solution, there was an increase in carbohydrate utilization, which was offset by absorption of glucose from the lumen. Intravenous administration of mefenamic acid significantly increased both carbohydrate absorption and metabolism when food was placed in the lumen. Changes in carbohydrate absorption and metabolism have been shown to play and important role in determining the magnitude of glucose induced changes in intestinal blood flow and oxygen consumption. Therefore, it is possible that the ability of mefenamic acid to enhance significantly the food-induced increases in blood flow and oxygen consumption may be due in part to its effects on intestinal carbohydrate absorption and utilization.