Despite differences in the phamacokinetics of 25-hydroxycholecalciferol (25(OH)D3) and 25-hydroxyergocalciferol (25(OH)D2) in man, the effects of these and their 1α-hydroxylated forms (1,25(OH)2D3 and 1,25(OH)2D2) on cellular activity of vitamin D-responsive cells have hardly been compared. We studied differences in the effects of these metabolites on cell number, gene transcription, protein ex...

In this study, the ligand-receptor-G protein interactions of the dopamine D3 receptor expressed in Chinese hamster ovary cells were investigated using guanosine 5'-[gamma-thio]triphosphate-[35S] ([35S]GTPgammaS) and receptor binding experiments. Dopamine stimulated the [35S]GTPgammaS binding in a guanine nucleotide, magnesium and sodium-dependent manner. Dopamine and quinpirole produced maximal...

Abstract Atopic dermatitis (AD) is a severe inflammatory skin disease. Langerhans cells and dendritic epidermal (IDEC) are located in the epidermis of AD patients contribute to processes. Both express robustly high-affinity receptor for IgE, Fc?RI, thereby sense allergens. A beneficial role vitamin D3 discussed be important especially with allergic sensitization. We hypothesized that impacts Fc...

OBJECTIVE Dopamine is an endogenous neuromodulator in cortical circuits and the basal ganglia. In animal models of temporal lobe epilepsy (TLE), seizure threshold is modulated to some extent by dopamine, with D1-receptors having a pro- and D2-receptors an anticonvulsant effect. We aimed to extend our previously reported results on decreased D2/D3 receptor binding in the lateral epileptogenic te...

We have previously identified a receptor for 1,25-dihydroxyvitamin D3 in myocardial cells (Simpson, R.U. 1983. Circulation. 68:239.). To establish the relevance of this observation, we evaluated the role of the prohormone vitamin D3 in regulating cardiovascular function. In rats maintained on a vitamin D3-deficient diet for nine weeks, increases in systolic blood pressure (BP) and serum creatin...

General knowledge of the role of vitamin D3 in human physiology has been shaped by its discovery as a preventive agent of nutritional rickets, a defect in bone development due to inadequate uptake of dietary calcium. Studies on the function of the biologically active vitamin D3, 1,25-dihydroxyvitamin D3, have been greatly accelerated by the molecular cloning and structural analysis of the vitam...

PURPOSE Vitamin D3 is a secosteroid mainly synthesized from the conversion of the skin precursor 7-dehydrocholesterol (7DHC) to vitamin D3 by ultraviolet (UV) B sunlight. Extrarenal synthesis of vitamin D3 has been reported in many tissues and cells, including barrier sites. This study characterizes the expression of components of vitamin D3 signaling in human ocular barrier cells. METHODS Pr...

The legend of Figure 1 was given incorrectly. Histidine should be corrected as histamine.

Vitamin D3 is a prohormone produced in skin through ultraviolet irradiation of 7-dehydrocholesterol. It is biologically inert and must be metabolized to 25-hydroxyvitamin D3 in the liver and then to 1alpha,25-dihydroxyvitamin D3 in the kidney before function. The hormonal form of vitamin D3, ie, 1alpha,25-dihydroxyvitamin D3, acts through a nuclear receptor to carry out its many functions, incl...

Differentiation of leukemic cells in vitro is characterized by the sequential appearance of morphological, functional, and biochemical markers of maturation. The interaction of insulin with its receptor may be a regulator of growth and differentiation of leukemic cells. Human promyelocytic leukemia cells (HL-60) demonstrate specific reversible insulin binding consistent with properties of human...