Vitamin D-Dependent Rickets in the Pig: Renal Handling of Amino Acids

2015 ◽  
pp. 162-166
Author(s):  
Claus v. Grabe ◽  
Johein Harmeyer
Keyword(s):  
Amino Acids ◽  
Vitamin D ◽  
Renal Handling

scholarly journals Cellular and metabolic mechanisms of nutrient actions in immune function

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Philip Newsholme
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
Vitamin D ◽  
Immune System ◽  
Cell Function ◽  
Immune Cell ◽  
Cell Structure ◽  
Nutritional Intervention ◽  
Immune Cell Function ◽  
And Function

AbstractVarious nutrients can change cell structure, cellular metabolism, and cell function which is particularly important for cells of the immune system as nutrient availability is associated with the activation and function of diverse immune subsets. The most important nutrients for immune cell function and fate appear to be glucose, amino acids, fatty acids, and vitamin D. This perspective will describe recently published information describing the mechanism of action of prominent nutritional intervention agents where evidence exists as to their action and potency.

The nutritional biochemistry of wool and hair follicles

2000 ◽  
Vol 70 (2) ◽  
pp. 181-195 ◽  
Author(s):  
P.I. Hynd
Keyword(s):  
Amino Acids ◽  
Vitamin D ◽  
Amino Acid ◽  
Vitamin A ◽  
Hair Follicle ◽  
Significant Activity ◽  
Direct Effects ◽  
Outer Root Sheath ◽  
Root Sheath ◽  
Fibre Growth

AbstractThe rôle of various classes of nutrients (energy substrates, vitamins, minerals, amino acids) in the production of wool and hair from follicles, is considered for a variety of animal species. The wool and hair follicle have evolved a number of interesting features of carbohydrate metabolism including glutaminolysis, aerobic glycolysis, significant activity of the pentose phosphate pathway, and storage and mobilisation of glycogen. Presumably the necessity to continue to produce fibre despite fluctuations in the supply of oxygen and nutrients has resulted in some of these unique features, while others reflect the high level of DNA and protein synthesis occurring in the follicle. While it is considered that energy does not normally limit fibre growth, the relative contributions of aerobic and anerobic metabolism will greatly influence the amount of ATP available for follicle activity, such that energy availability may at times alter fibre growth. Alopecia and deficient fibre growth are consistent outcomes of deficiencies of biotin, riboflavin, pyridoxine, folate and pantothenic acid, but the precise rôles of these vitamins in follicle function await elucidation. Folate, in particular appears to play an important rôle in wool production, presumably reflecting its involvement in methionine metabolism. Cholecalciferol (vitamin D) significantly alters fibre growth in cultured follicles; vitamin D receptors are located in the outer root sheath, bulb, and dermal papilla of the follicle; and alopecia occurs in humans with defects in the vitamin D receptor. Retinol (vitamin A), too, appears to influence follicle function by altering keratinocyte proliferation and differentiation, with direct effects on the expression of keratin genes. The receptors for the retinoids are present in the keratogenous zone, the outer root sheath, the bulb, and the sebaceous glands. Vitamin A may also act indirectly on follicle function by influencing the activity of the insulin-like and epidermal growth factors and by altering vitamin D activity. At present there is little evidence implicating alpha-tocopherol (vitamin E) or phytylmenaquinone (vitamin K) in follicular events. Of the minerals, only copper and zinc have been shown to have direct effects on follicle function, independent of effects on food intake. Copper has direct effects on the activity of an unidentified enzyme on oxidation of thiol groups to form disulphide linkages. Wool produced by copper-deficient sheep lacks crimp, is weak and lustrous. Copper is also necessary for the activity of tyrosinase and the tyrosinase-related proteins involved in melanin synthesis. Zinc, like copper, is required for the normal keratinization of fibres but again, the precise rôle has yet to be elucidated. While the importance of amino acid supply for wool growth has long been established, there are still some unaswered questions such as; what are the effects of amino acids on fibre growth in animals other than sheep; what are the characteristics of the amino acid transport genes and proteins operating in the wool and hair follicle; and what are the specific rôles for amino acids in follicle function.

scholarly journals 74 Hyperexcretion of Urinary Amino Acids and Phosphorus in the Vitamin D-Deficient Holtzman Rat

1967 ◽  
Vol 1 (3) ◽  
pp. 219-219
Author(s):  
John Grose ◽  
Charles Scriver ◽  
John Fawcett
Keyword(s):  
Amino Acids ◽  
Vitamin D ◽  
Urinary Amino Acids ◽  
Urinary Amino

scholarly journals Intron retention generates a novel isoform of the murine vitamin D receptor that acts in a dominant negative way on the vitamin D signaling pathway.

1996 ◽  
Vol 16 (7) ◽  
pp. 3393-3400 ◽  
Author(s):  
K Ebihara ◽  
Y Masuhiro ◽  
T Kitamoto ◽  
M Suzawa ◽  
Y Uematsu ◽  
...  
Keyword(s):  
Amino Acids ◽  
Vitamin D ◽  
Ligand Binding ◽  
Signaling Pathway ◽  
Vitamin D Receptor ◽  
Target Genes ◽  
Stop Codon ◽  
Dominant Negative ◽  
Transient Expression Assay ◽  
Vitamin D Signaling

We identified and characterized a novel rat vitamin D receptor isoform (rVDR1), which retains intron 8 of the canonical VDR (rVDR0) during alternative splicing. In this isoform protein directed by the stop codon in this newly identified exon, a part of the ligand binding domain (86 amino acids) is truncated at the C-terminal end but contains 19 extra amino acids. The rVDR1 transcript was expressed at a level 1/15 to 1/20 of that of rVDR0 in the kidney and intestine in adult rats but not in embryos. The recombinant rVDR1 protein showed no ligand binding activity. Homo- and heterodimers of the recombinant rVDR0 and rVDR1 proteins bound to a consensus vitamin D response element (VDRE) but not to consensus response elements for thyroid hormone and retinoic acid. However, unlike rVDR0, rVDR1 did not form a heterodimeric complex with RXR on the VDRE. A transient expression assay showed that this isoform acted as a dominant negative receptor against rVDR0 transactivation. Interestingly, the dominant negative activities of rVDR1 differed among VDREs. Thus, the present study indicates that this new VDR isoform negatively modulates the vitamin D signaling pathway, through a particular set of target genes.

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