Vitamin D Council Glossary

# A B C D E F G H I J–K L M N O P R S T U V
S-adenosyl-L-methionine (SAMe)
A direct metabolite of the essential amino acid L-methionine and the methyl-group donor in the biosynthesis of DNA and RNA nucleic acids, phospholipids, proteins, epinephrine, melatonin, creatine, and other molecules.
Cell-cycle period during which DNA replication takes place.
Seasonal Affective Disorder (SAD)
Winter depression that is caused by decreased sunlight and is more prevalent at higher latitudes. Symptoms include feelings of depression, lethargy, fatigue, cravings for sweets and starches, headaches, sleep problems, and irritability.
A molecule that is similar in structure to a steroid, except two of its four B-ring carbon atoms (C9 and 10) are un-joined. Vitamin D is the most important secosteroid in the human body.
Serotonin (also called 5-hydroxytryptamine) is a hormone in the pineal gland, digestive tract, brain, and blood platelets. Serotonin acts both as a chemical messenger that transmits nerve signals between nerve cells and that causes blood vessels to narrow. Changes in serotonin levels in the brain can alter mood.
Deadly collagenous and inflammatory pneumoconiosis caused from inhaling sand dust.
Single nucleotide polymorphism (SNP)
A variation of a single nucleotide of DNA useful in understanding and identifying a higher risk of a disease in particular people.
Vitamin D5. Produced by irradiating 7-dehydrositosterol.
Sequential multi-channel analysis. A group of chemical tests performed on serum (the portion of blood without cells) to measure the levels of chemical substances released from various tissues in the body.
Somatic Nervous System (SNS)
Includes all nerves controlling the muscular system and external sensory receptors.
Spectrum Disorder
Group of disorders with similar features where one person may have mild symptoms, while another might have serious symptoms.
ST segment
The period from the end of ventricular depolarization to the beginning of ventricular repolarization on an Electrocardiogram. If elevated or depressed, can be a sign of ischemia and hyperkalemia.
Steroid hormone
Steroid that acts as a hormone by binding to and activating receptor molecules that serve to regulate gene expression.
Steroid hormone receptor
Intracellular receptor that performs signal transduction for steroid hormones and is part of the nuclear receptor family.
Steroid that provides important signals and metabolic communications such as circadium rythms, blood clotting, etc. Vitamin D derivatives are sterols.
Molecule which is acted upon by an enzyme.
Substrate inhibition
Inhibition of an enzyme activity by a substrate of the reaction catalyzed by that enzyme.
Sunlight, Nutrition, and Health Research Center.
Syndrome X
Also known as insulin resistance, metabolic syndrome, glucose intolerance, prediabetes. A disease caused by your body's inability to make the most of the food you eat, increasing the risk for obesity, hypertension, nervous system disorders, eye disease, diabetes, cardiovascular disease, cancer, and Alzheimer's disease.

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