Endogenous biotin can be found in which tissues?

Endogenous biotin can be found in which tissues?

• A. Brain and Heart
• B. Liver and Kidney
• C. Lung and Spleen
• D. Muscle and Skin

Answer: (B)

Endogenous biotin is most abundant in tissues with high metabolic activity and many biotin-dependent enzymes. The liver and kidney fit this, because they house abundant biotin-dependent carboxylases (such as pyruvate carboxylase and acetyl-CoA carboxylase) and are central to biotin metabolism and reabsorption. As a result, these organs have higher baseline biotin levels than other tissues, making them the best choice for where endogenous biotin is found. In practical immunohistochemistry using avidin-biotin detection, this higher biotin content can lead to background staining, so a biotin-blocking step or a non-biotin detection method is often used. Other tissues may contain some biotin, but at lower levels, which is why liver and kidney are the correct focus here.

Endogenous biotin is most abundant in tissues with high metabolic activity and many biotin-dependent enzymes. The liver and kidney fit this, because they house abundant biotin-dependent carboxylases (such as pyruvate carboxylase and acetyl-CoA carboxylase) and are central to biotin metabolism and reabsorption. As a result, these organs have higher baseline biotin levels than other tissues, making them the best choice for where endogenous biotin is found. In practical immunohistochemistry using avidin-biotin detection, this higher biotin content can lead to background staining, so a biotin-blocking step or a non-biotin detection method is often used. Other tissues may contain some biotin, but at lower levels, which is why liver and kidney are the correct focus here.