November 8 notes - Summary of last lecture De novo...

Info iconThis preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
Summary of last lecture De novo synthesis of vitamin D Alternative pathways for conversion of vitamin D to prevent toxicity Conversion of parent compound (vitamin D 3 ) to its active form (1,25-(OH) 2 D 3 ) via the liver and kidney Determinants of 25-OH D 3 status Age Skin pigmentation Diet UV exposure
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Calcium Homeostasis: Three Hormones i) PTH Low blood Ca stimulates release of PTH from parathyroid glands stimulates synthesis of 1-hydroxylase produces 1,25-(OH) 2 D 3 Elevated serum 1,25-(OH) 2 D 3 decreases gene transcription of pre-PTH Elevated ionized calcium reduces PTH secretion 209
Background image of page 2
210
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
ii) 1,25-(OH) 2 D 3 kidney, intestine and bone iii) Calcitonin synthesized and secreted by cells of thyroid gland high plasma Ca stimulates secretion counter-regulatory to PTH acts at bone to inhibit osteoclastic bone resorption 211
Background image of page 4
Summary: Roles of 1,25-(OH) 2 D 3 (Fig 10.14) Blood calcium maintained in normal range by: dietary Ca absorption through intestine – by 1,25-(OH) 2 D 3 Ca mobilization (resorption) from bone – by PTH and 1,25-(OH) 2 D 3 Ca reabsorption from kidney – by PTH and 1,25-(OH) 2 D 3 212
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Disorders of Vitamin D Metabolism Causing Bone Defects A. Gene defects in Vitamin D metabolism or VDR causing rickets A. Nutritional rickets (diet/environment) 213
Background image of page 6
A. Genetic Disorders of Vitamin D Associated Rickets Characterized in
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 21

November 8 notes - Summary of last lecture De novo...

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online