absorption and metabolism of vitamin a

... 20,23-dihydroxyvitamin D3 and 1 7a, 20,23-trihydroxyvitamin D3 The major pathway of vitamin D3 metabolism by cytochrome P450scc involves initial hydroxylation at C20 followed by hydroxylations at C23 and ... hydroxylation of vitamin D3 at position 22 now provides a clear explanation for the inability of P450scc to cleave the side chain of vitamin D3 Hydroxylation of the side chain of cholesterol at the adjacent ... with vitamin D3 1 7a, 20-Dihydroxyvitamin D3 and 1 7a, 20,23-trihydroxyvitamin D3 also dissociate from the P450scc in Fig Pathways for the metabolism of vitamin D3 by P450scc The major pathway is...

Ngày tải lên: 18/02/2014, 17:20

... (2000) Activation of rabbit blood platelets by anandamide through its cleavage into arachidonic acid FEBS Lett 471, 12–16 Ó FEBS 2003 43 Fasia, L & Siafaka-Kapadai, A (1997) Effects of anandamide and ... that anandamide crossed the platelet plasma membrane by simple diffusion and not by a carriermediated transport Again, the accumulation of [3H]anandamide in platelets was higher at 0–4 °C than ... of FAAH activity which is localized mainly in the plasma membrane-rich fraction of rabbit platelets and is much higher than that in human platelets (L Fasia and A Siafaka, unpublished data) Moreover,...

Ngày tải lên: 08/03/2014, 08:20

... non-mycorrhizal or either Metabolism of these amino acids and a 4th amino acid, glycine, was affected both by type of amino acid and by mycorrhizae After a h uptake period, little glycine had been metabolized ... very small amount of anion influx was balanced by bicarbonate efflux Most cations were presumably stored in vacuoles as salts of organic acids Our calculations suggest that both mycorrhizal and ... wall/free space, cytoplasm and vacuole was There was rapid influx and efflux of potassium About 95% of all potassium entering roots was subsequently released; net accumulation was only 5% of total flux...

Ngày tải lên: 09/08/2014, 04:20

... criteria is supported by the majority of experts and is based on studies of relationships between plasma 25(OH)D level and plasma parathomone, calcium absorption in guts and consequences of vitamin ... PES: Partial Eta Squared Vitamin D status was significantly associated with HOMA2IR-In (p = 0,028) and HOMA2-IR-Cp (p = 0,009) in the analysis of covariance model (tab 3.9) 3.5 Effects of vitamin ... 1.1.4 Recommendations on vitamin D supplementation and treatment of vitamin D deficiency There has not been also a widespread concensus on vitamin D supplementation and treatment of vitamin D deficiency...

Ngày tải lên: 11/05/2016, 08:56

... Function A Bannink and S Tamminga 263 METABOLISM 11 Glucose and Short-chain Fatty Acid Metabolism R.P Brockman 291 12 Metabolism of the Portal-drained Viscera and Liver D.B Lindsay and C.K Reynolds ... research into digestion and metabolism in ruminants, as in many other areas of biology, has been empirically based and has centred on statistical analysis of experimental data Whilst this has ... methods have advantages and disadvantages that influence their suitability for a given application, affect the mathematical model that is needed, and alter interpretation of results Regardless of the...

Ngày tải lên: 24/10/2013, 17:15

... 389–410 Warren, W.P., Martz, F .A. , Asay, K.H., Hilderbrand, E.S., Payne, C.G and Vogt, J.R (1974) Digestibility and rate of passage by steers fed tall fescue, alfalfa and orchardgrass hay in 18 and ... at a constant rate throughout gestation Australian Journal of Agricultural Research 30, 493–504 Faichney, G.J., Poncet, C and Boston, R.C (1989) Passage of internal and external markers of particulate ... and Williams, V.J (1973) Rate of passage of digesta in sheep Passage of marker through the alimentary tract and the relevance of rate constants derived from the changes in concentration of marker...

Ngày tải lên: 24/10/2013, 17:15

... in lower and more variable disappearance rates, whereas too small particles are associated with greater mechanical losses of ´n material from the bags (Weakley et al., 1983; Ude and Van Soest, ... procedures are standardized to increase precision, as lack of standardization has been reported as the main source of variation in the assay (Madsen and Hvelplund, 1994) As for the animal effects, ... degradation and the uptake of ammonia for the synthesis of microbial protein The amount and nature of fermentable substrates also affect ammonia concentrations, as uptake by microbes is stimulated...

Ngày tải lên: 29/10/2013, 00:15

... Central pith Fig 5.2 Conceptual representation of the breakdown process of (A) leaves of tropical and temperate grasses and of legumes, and (B) mature stems of grass and legume, during eating and ... total cell wall area was exposed on the outside of chewed particles of legume leaflets and grass leaf blades and sheaths, whereas stem fragments were larger, and only 3–4% of cell wall area was ... was available, our ability to explain the interaction of mastication and plant anatomy would be greatly enhanced A pertinent approach was made by Murphy and Bohrer (1984) From data for sheep of...

Ngày tải lên: 29/10/2013, 00:15

... sheep given a diet of hay and concentrates assimilated both 14 C-labelled peptides and free AA and their intracellular metabolism was also rapid (Armstead and Ling, 1993) Free AA are taken up from ... (Tamminga, 1990) Bacteria contain proteins that are readily digested in the small intestine and have a well-balanced, though less than ideal, array of essential AA The essential AA profiles of ... R.J and Ørskov, E.R (1991) Control of rate and extent of protein degradation In: Tsuda, T., Sasaki, T and Kawashima, R (eds) Physiological Aspects of Digestion and Metabolism in Ruminants Academic...

Ngày tải lên: 07/11/2013, 23:15

... converted to acetate or propionate Methanogenic archaebacteria such as Methanobrevibacter ruminantium and Methanosacina barkeri utilize either H2 and CO2 or formate, acetate, methylamine and methanol ... mechanical resistance of particles, allowing increased bacterial attack on those damaged particles and possible coexistence of fungi and bacteria (Dijkstra and France, 1997; Fonty et al., 1999) In addition ... production and portal appearance of volatile fatty acids in dairy cows In: McNamara, J.P., France, J and Beever, D.E (eds) Modelling Nutrient Utilization in Farm Animals CAB International, Wallingford,...

Ngày tải lên: 07/11/2013, 23:15

... nitrogen availability is a function of protein degradation rates, the peptide uptake rate and the relative utilization of ammonia and amino N by NFC bacteria FC bacteria are assumed to use only ammonia ... cost of amino acid transport was greater than the cost of amino acid biosynthesis; and (iii) ammonia was taken up by active transport Mixed ruminal bacteria utilize peptides at a faster rate than ... growth of strictly anaerobic bacteria (Clarke, 1977) In virtually all cases, strict anaerobes outnumber facultative anaerobes and aerobes by a factor of at least 10,000 to Because oxygen is not available...

Ngày tải lên: 07/11/2013, 23:15

... in this way accurate estimates of actual losses of N as ammonia absorbed from the rumen are obtained An analysis on the rumen N balance was made of observations available in the database used ... Tamminga and Chen (2000) Variation of the fractional passage rate of particulate material influences the retention time and hence the amount of NDF available for microbial degradation Several ... feed evaluation systems largely ignore the effects of variation in rumen pH and passage rates, and the fractional rates of degradation and passage are as yet considered independent of each other...

Ngày tải lên: 15/12/2013, 08:15

... UFA Early, basal Early, UFA Medium, basal Medium, UFA Early, basal Early, UFA Medium, basal Medium, UFA Early, basal Early, UFA Medium, basal Medium, UFA Insulin Gut glucagon Pancreatic glucagon ... uptake of lactate by the mammary gland of lactating animals is equal to about 20% of its glucose uptake on a molar basis (Oddy et al., 1985) The liver uses more of the lactate, and is normally a ... et al (199 1a) The authors studied exchange of Na, K, Ca, P and Mg in dairy cattle, first in lactating animals and then in a dietary study comparing hay and concentrate diets Portal vein and arterial...

Ngày tải lên: 15/12/2013, 08:15

... Fazakerly, S and Nichols, B.W (1967b) The oxidation and utilisation of palmitate, stearate, oleate and acetate by the mammary gland of the fed goat in relation to their overall metabolism, and ... the mammary gland in fed goats (Annison et al., 1967b), there was a marked gross uptake indicating a large simultaneous release and uptake of NEFA due to the action of LPL on plasma TAG (Annison, ... dilution A potassium soap of radiolabelled fatty acids is dissolved in plasma and infused intravenously at a constant rate After about h the specific radioactivity of plasma NEFA in arterial blood...

Ngày tải lên: 15/12/2013, 09:15

... Protein synthesis and degradation in the mammary gland of lactating goats Journal of Dairy Research 55, 143–154 ´ Patureau Mirand, P., Bernard, O., Prugnaud, J and Arnal, M (1985) Metabolisme ´ ´ ... 43–59 MacRae, J.C., Walker, A. , Brown, D and Lobley, G.E (1993) Accretion of total protein and individual amino acids by organs and tissues of growing lambs and the ability of nitrogen balance ... many mRNAs are also subject to translational control, and the relative amount of any mRNA depends on both rates of transcription and of mRNA breakdown Finally, there are frequent discrepancies...

Ngày tải lên: 15/12/2013, 09:15

... post-translational energy costs The general acceptance of ATP/bond is based on ATP for AA activation, ATP for bond formation, ATP for translocation and ATP for AA transportation, RNA production and associated ... production and enhance energy efficiency of the animal through the use of fumarate and malate as feed additives that would serve as electron acceptors The importance of AA, peptides and ammonia as substrates ... extracellular and intracellular free specific radioactivity Wolfe (2002) noted that AA concentrations are able to maintain the charge of tRNA in a variety of situations, and it is unlikely that tRNA charging...

Ngày tải lên: 15/12/2013, 09:15

... reciprocal changes in the amount of mRNA, total enzyme activity (Table 17.5) and activation status of ACC -a in adipose tissue and mammary gland (Travers et al., 1997) The proportionately greater changes ... fatty acids, Ca2þ and Pi, increased Synthesis and secretion of protein, lipid and lactose increased Secretion of Ca2þ and Pi increased Absorptive capacity increased Increased Increased Heart Adipose ... Uptake of glucose and acetate may decrease; uptake of fatty acids increased Output of lactate, amino acids increased Protein synthesis decreased; proteolysis increased Decreased ? Uptake and accretion...

Ngày tải lên: 15/12/2013, 09:15

... (hypertrophy), and includes the deposition of substantial amounts of extracellular matrix material (e.g collagen and mineral) in cartilage and bone, extracellular fluids and electrolytes and accumulation of ... paraventricular and dorsomedial hypothalamus (Tartaglia et al., 1995) It serves as an indicator of energy status especially adipose stores and is a postprandial satiety signaller (Houseknecht et al., ... and soft tissues (4)) and P enters the system via intake (F10 ) and exits via faeces (F 01 ) and urine (F 02 ) The daily intake and loss of P in faeces and urine were measured by chemical analysis...

Ngày tải lên: 15/12/2013, 09:15

... hyperinsulinaemia and hypoaminoacidaemia caused substantial reductions in uterine, uteroplacental and fetal uptakes of several amino acids, particularly the branched-chain acids, and a 60% reduction ... umbilical bloodstream (Chung et al., 1998) Quantitative aspects of ovine placental metabolism and fetal–placental exchanges of branched-chain amino acids, glutamine, glutamate and their metabolites ... while maintaining basal fetal glycaemia (DiGiacomo and Hay, 1990b) Effects of amino acid supply on fetal metabolism have not been studied systematically Decreased maternal plasma concentrations of...

Ngày tải lên: 15/12/2013, 09:15

... Glucose oxidation (mol/day) dTAa/dt (mol/day) ¼ TabsAa þ TPbAaB þ TPvAaV À TAaPbB À TAaPvV À TAaPmV À TAaSAL À TAaDEG À TAaPRG TAa ¼ Total amino acids in plasma (mol) TabsAa ¼ Total amino acid absorption ... (VAaLA *UENZ *kminh /(1.0þ((kAaLA/cAa)EXPAa)))/fLAAa SAaLA1 ¼ (VSAaLA *UENZ *kminh /(1.0þ((kSAaLA/cSAa)EXPSAa)))/fLASAa LysLA1 ¼ (VLysLA *UENZ *kminh /(1.0þ((kLysLA/cLys)EXPLys)))/fLALys HisLA1 ... propionic acid (AbsPr) Ammonia (Am) Absorbed glucose (AbsGl) PrGlV Saliva Lactate in gut (GGlLa) Urea CO2 TAaDEG Oxidation (BuCd) TAaAc Plasma acetate (Ac) Plasma total amino acids (TAa) Made up of...

Ngày tải lên: 15/12/2013, 09:15