Which of the following is not a function of progesterone?

Options

A. Gestation
B. Stimulation of mammary secretion
C. Inhibition of ovulation
D. Uterine growth and development

Answer

To determine which of the following is not a function of progesterone, we will analyze the options provided: gestation, stimulation of mammary secretion, inhibition of ovulation, and uterine growth and development.

### Step-by-Step Solution:

1. **Understand the Role of Progesterone**:
- Progesterone is a steroid hormone primarily produced by the corpus luteum in the ovaries after ovulation. It plays a crucial role in the menstrual cycle and in maintaining pregnancy.

2. **Evaluate Each Option**:
- **Gestation**: Progesterone is essential for maintaining pregnancy. It prepares the endometrium (the inner lining of the uterus) for implantation of the fertilized egg and supports the pregnancy.
- **Stimulation of Mammary Secretion**: This function is not performed by progesterone. Instead, it is primarily regulated by oxytocin, which is secreted by the posterior pituitary gland. Therefore, this option is likely to be the correct answer.
- **Inhibition of Ovulation**: Progesterone prevents the release of further eggs during the menstrual cycle, thereby inhibiting ovulation.
- **Uterine Growth and Development**: Progesterone promotes the growth and development of the uterine lining, making it suitable for implantation and supporting the developing fetus.

3. **Identify the Correct Answer**:
- After analyzing the functions of progesterone, we find that the stimulation of mammary secretion is not a function of progesterone. The correct answer is **stimulation of mammary secretion**.

### Final Answer:
The option that is not a function of progesterone is **stimulation of mammary secretion**.

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