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==What is Vitamin B7 (Biotin)?==

==What is Vitamin B7 (Biotin)?==

'''Vitamin B₇''', also called '''biotin''', is an '''essential water-soluble vitamin'''. Biotin is actively transported across the intestinal mucosa, with minimal passive [[Diffusion - Physiology|diffusion]], and is typically found as free biotin in [[plasma]]. '''Biotin is not stored in the body and is freely filtered by the [[Nephron Microscopic Anatomy#Proximal Tubule|renal tubules]]'''.  

'''Vitamin B₇''', also called '''biotin''', is an '''[[Nutrition Glossary#Essential Nutrients|essential]] water-soluble vitamin'''. Biotin is actively transported across the intestinal mucosa, with minimal passive [[Diffusion - Physiology|diffusion]], and is typically found as free biotin in [[plasma]]. '''Biotin is not stored in the body and is freely filtered by the [[Nephron Microscopic Anatomy#Proximal Tubule|renal tubules]]'''.

==Why is it Important?==

==Why is it Important?==

==Roles in the Body==

==Roles in the Body==

Biotin is an essential component of 4 carboxylase enzymes<ref>Sweetman L. Pantothenic Acid and Biotin. In Biochemical and physiological aspects of human nutrition. 2000 Philadelphia, PA: WB Saunders Company p.529-540.</ref>:

Biotin is an essential component of 4 carboxylase enzymes<ref>Sweetman L. Pantothenic Acid and Biotin. In Biochemical and physiological aspects of human nutrition. 2000 Philadelphia, PA: WB Saunders Company p.529-540.</ref>:

#'''Pyruvate carboxylase''', which converts pyruvate to oxaloacetate (OAA) during [[Carbohydrate Overview - Nutrition|carbohydrate]] metabolism;  

#'''Pyruvate carboxylase''', which converts pyruvate to oxaloacetate (OAA) during [[Carbohydrates Overview - Nutrition|carbohydrate]] metabolism;  

#'''Acetyl CoA carboxylase''', which is the rate limiting enzyme step in conversion of acetyl CoA to malonyl CoA in fatty acid synthesis;  

#'''Acetyl CoA carboxylase''', which is the rate limiting enzyme step in conversion of acetyl CoA to malonyl CoA in [[Fatty Acids Overview - Nutrition|fatty acid]] synthesis;  

#'''Propionyl CoA carboxylase''', which carboxylates propionyl CoA (from [[Protein Overview - Nutrition|amino acid]], [[Fatty Acids - Nutrition|fatty acid] or carbohydrate metabolism) into methylmalonyl CoA; and  

#'''Propionyl CoA carboxylase''', which carboxylates propionyl CoA (from [[Protein Overview - Nutrition|amino acid]], fatty acid or carbohydrate metabolism) into methylmalonyl CoA; and  

# '''3-methylcrotonyl CoA carboxylase''', which functions in the catabolic pathway for leucine.

# '''3-methylcrotonyl CoA carboxylase''', which functions in the catabolic pathway for [[Branched-Chain Amino Acids - Nutrition|leucine]].

==Consequences of Biotin Deficiency==

==Consequences of Biotin Deficiency==

==Toxicity==

==Toxicity==

There are no published reports of biotin toxicity in dogs and cats<ref name="NRC"/>; excess intake is freely filtered through the renal tubules.

There are no published reports of biotin toxicity in dogs and cats<ref name="NRC"/>; excess intake is [[:Category:Urine Production|freely filtered through the renal tubules]].

==Dietary Sources==

==Dietary Sources==

High concentrations of naturally occurring biotin are found in meats, dairy products, grains, and pulses (e.g., legumes). Because endogenous microbial synthesis is normally adequate, a dietary supply of biotin is not required. However supplementation may be necessary in situations where intestinal microbial synthesis is compromised, such as long term administration of anti-bacterial agents.

High concentrations of naturally occurring biotin are found in meats, dairy products, grains, and pulses (e.g. legumes). Because endogenous microbial synthesis is normally adequate, a dietary supply of biotin is not required. However supplementation may be necessary in situations where intestinal microbial synthesis is compromised, such as long term administration of [[Antibiotics|anti-bacterial agents]].

==Diagnosing Biotin Deficiency==

==Diagnosing Biotin Deficiency==

==References==

==References==

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[[Category:Vitamins]]

[[Category:Vitamins]]