Question

Which of the following is a female hormone ?

• A. Estradial
• B. Methyl testosterone
• C. Ethyl testosterone
• D. Nor ethindrone

Hint:

Key hormones in Aquaculture:
1. Estradiol $\rightarrow$ For Feminization.
2. Methyl-testosterone $\rightarrow$ For Masculinization (Sex reversal).
3. GtH (Gonadotropins) $\rightarrow$ For Induced breeding.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The question asks to identify a hormone that is primarily associated with female reproductive functions and characteristics in animals, including fish.
Detailed Explanation:

• Estradial (A): More commonly spelled as Estradiol (specifically 17$\beta$-estradiol), it is the primary estrogen found in vertebrates. It is secreted by the granulosa cells of the ovary. In fish, it plays a crucial role in vitellogenesis (the process of yolk formation in the liver).

• Function: It stimulates the liver to produce vitellogenin, which is then transported through the blood to the developing oocytes. It is also responsible for the development of female secondary sexual characteristics.

• Analysis of other options:
• Methyl testosterone (B): This is a potent synthetic androgen (male hormone). It is widely used in aquaculture for "sex reversal" to produce all-male populations (e.g., in Tilapia).

• Ethyl testosterone (C): Another synthetic androgen.

• Nor ethindrone (D): A progestin used in human contraceptives; it is not the primary "female hormone" used in a general biological or fisheries context.

Step 2: Final Answer:
Estradial (Estradiol) is the primary female hormone.