Question

Secretion of progesterone by corpus luteum is initiated by

• A. thyroxine
• B. testosterone
• C. LH
• D. MSH

Answer 1

The correct option is C

LH

The correct option is C.

Explanation of the correct option:

Option A:

1. LH is known as the luteinizing hormone.
2. LH is secreted by the pituitary gland located at the base of the brain.
3. LH functions to induce ovulation and helps in maintaining the corpus luteum, which is formed by remnants of Graafian follicles (fluid-filled structure of the mammalian ovary).
4. The LH surge occurs around the 14th day of the menstrual cycle and induces ovulation.
5. For the next two weeks after ovulation, LH is required to sustain luteal function.
6. The LH hormone helps in the secretion of progesterone which is the essential pregnancy hormone as it induces the thickening of the endometrial wall.

Explanation of the incorrect options:

Option A:

1. Thyroxine is known as the T4 hormone produced by the thyroid gland in the neck.
2. It helps in regulating the body's metabolism along with the the T3 hormone.

Option B:

1. Testosterone is a steroidal male sexual hormone produced by the testes.
2. It helps in maturing the secondary male sexual characteristics and regulates male sex libido.

Option D:

1. MSH is known as the melanocyte-stimulating hormone.
2. It helps in the rapid translocation of melanin granules (melanosomes) in dermal melanophores to effect rapid colour change.
3. It also helps in the melanogenesis in normal and abnormal (melanoma) epidermal melanocytes.

Final answer: Secretion of progesterone by corpus luteum is initiated by LH.