Question

Detoxification of drugs and chemicals in fish is predominantly carried out by

• A. Gills
• B. Liver
• C. Kidney
• D. Intestine

Hint:

In any vertebrate biology exam:
- Metabolism/Detoxification = Liver.
- Excretion of Solids = Kidney.
- Excretion of Gases/$NH_3$ = Gills (in fish).

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question asks to identify the primary organ responsible for the metabolic breakdown (biotransformation) and detoxification of xenobiotics (foreign chemicals/drugs) in fish.
Detailed Explanation:

• Role of the Liver: In fish, as in mammals, the liver is the central metabolic hub. It contains a high concentration of detoxifying enzymes, most notably the Cytochrome P450 (CYP) system (Phase I reactions) and various transferases (Phase II reactions).

• Metabolism Process: These enzymes convert lipophilic (fat-soluble) drugs into more hydrophilic (water-soluble) metabolites, which can then be easily excreted through the bile or urine.

• Other Organs:
• Gills (A): Primarily for gas exchange and excretion of simple metabolic waste like ammonia.

• Kidneys (C): Primarily for excretion of the water-soluble metabolites produced by the liver.

• Intestine (D): Can perform some first-pass metabolism, but the liver's capacity is much greater.

Step 3: Final Answer:
The liver is the predominant organ for the detoxification of drugs and chemicals in fish.