Vitamin D Council Glossary

Dendrite

A branching extension from the neuron cell body that receives information from other neurons.

Dendritic cells

Immune cells that play a crucial role in the initiation of T-cell-mediated immunity due to their potent antigen-presenting function.

Dentin

A calcified tissue of the body and the major component of teeth.

Deoxyribonucleic acid (DNA)

Nucleic acid that contains the genetic instructions for the development and functioning of living organisms.

DEQAS (Vitamin D External Quality Assessment Scheme)

International monitoring program that evaluates the accuracy of vitamin D level testing in the United Kingdom.

Diabetes mellitus

A metabolic disorder in which blood sugar (glucose) levels are abnormally high because the body does not produce enough insulin to move the sugar into cells.

Dietary Reference Intake (DRI)

The daily amount of a nutrient needed to maintain health, prevent nutrient deficiencies, and reduce risk of chronic disease as established by the Food and Nutrition Board of the Institute of Medicine.

Dihydrotachysterol (DHT)

Vitamin D analog that is a synthetic reduction product of tachysterol, a close isomer of vitamin D.

Dihydrotachysterol2

Vitamin D analog that is hydroxylated in vivo to 25OHDHT2 and 1,25OH2DHT2, both of which may suppress PTH gene transcription.

Dihydroxyphenylalanine (DOPA)

Naturally-occurring amino acid made from L-Tyrosine that is converted into dopamine in the human body. Dihydroxyphenylalanine (DOPA) is also found in food and is sold as a dietary supplement and prescription drug in the United States.

Dopamine

An important neurotransmitter in the brain.

Doxercalciferol (1α-hydroxyvitamin D2,1α(OH)D2,1α-hydroxyergocalciferol)

Vitamin D analog that is similar to alfacalcidol in that it is hydroxylated in the liver to 1α,25(OH2)D2. Doxercalciferol is also 24-hydroxylated to produce 1α,24(S)-(OH)2D2 (a metabolite with prodifferentiation actions), whereas alfacalcidol is not.

DU 145

Human prostate cancer cell line.