Vitamin D Metabolism and Disorders Quiz

What are the symptoms of Vitamin D toxicity in adults?

What is the consequence of excessive Vitamin D supplementation in some infants?

Why does excessive exposure to sunlight not lead to Vitamin D toxicity?

What is the negative effect of Vitamin D toxicity on soft tissues?

Which form of Vitamin E is considered the most active?

What symptom is associated with hypercalcemia due to Vitamin D toxicity?

Which enzyme is responsible for the hydroxylation of cholecalciferol at C-25 in the liver?

What is the active form of vitamin D that is formed after hydroxylation at both C-25 and C-1?

What controls the enzyme 1-hydroxylase in the kidney?

In cases of normal or hypercalcemia, which form of Vitamin D is predominantly formed?

What stimulates the synthesis of Ca-binding protein by Vitamin D?

Which condition may lead to vitamin D deficiency according to the text?

What are the symptoms of Vitamin A toxicity as mentioned in the text?

Which of the following is not a symptom of Vitamin A toxicity according to the text?

What can happen if Vitamin A intake exceeds the capacity of RBP (retinol binding protein)?

What is a symptom of Vitamin A deficiency according to the text?

Corticosteroids inhibit Vitamin D (VD) activation: normal range is 10-50 ng% for 25-OHVD and 15-45 pg/ml for 1,25-DHVD
In children, deficiency results in rickets, characterized by protruding abdomen and bone deformities
In adults, VD deficiency results in osteomalacia, characterized by fragile bones, especially in females
Toxicity from excessive supplementation can lead to high blood pressure, kidney and myocardial calcinosis, hypercalcemia, and kidney stones
VD is synthesized from cholesterol in the skin through ultraviolet light
Vitamin E (α-tocopherol) is essential for antioxidant activity and fat metabolism, synthesized in the body and found in vegetable oils, lettuce, and legumes
After absorption, VD is transported to the liver, hydroxylated to its active form (1,25-dihydroxycholecalciferol or calcitriol) in the kidney
Parathyroid hormone, calcium, and phosphate levels regulate the activation of calcitriol
Vitamin A (retinol) plays a role in growth, development, and immune function, deficiency results in night blindness and increased susceptibility to infectious diseases
Retinol and retinoic acid have antioxidant and anti-cancer properties
Carotenes are antioxidants, effective at low oxygen concentrations
Vitamin A deficiency causes night blindness and xerophthalmia, leading to corneal and skin dryness and blindness
Vitamin D is a steroid hormone, not sensitive to oxygen, and resistant to alkalies and high temperatures
Sources of Vitamin D include fish, milk, eggs, and cod liver oil.

Test your knowledge on vitamin D metabolism, related disorders like rickets and osteomalacia, symptoms of deficiency and toxicity, as well as the effects of corticosteroids on vitamin D conversion.