Question

Which among the following hormones is not produced by placenta?

• A. Human Chorionic Gonadotropin (hCG)
• B. Human Placental Lactogen (hPL)
• C. Estrogens
• D. Relaxin

Hint:

Important placental hormones: \[ \text{hCG, hPL, Estrogens, Progesterone} \] Relaxin is mainly secreted by the corpus luteum.

Answer 1

The Correct Option is D

Concept: The placenta is a temporary endocrine structure formed during pregnancy. It establishes physiological connection between mother and fetus and performs several important functions such as:

• Exchange of nutrients
• Exchange of respiratory gases
• Removal of fetal wastes
• Secretion of hormones

Placental hormones are extremely important for maintenance of pregnancy, fetal growth, maternal metabolic regulation, and preparation for childbirth. The major hormones secreted by placenta include:

• Human Chorionic Gonadotropin (hCG)
• Human Placental Lactogen (hPL)
• Estrogens
• Progesterone

Step 1: Analyze option (A) Human Chorionic Gonadotropin (hCG).
Human Chorionic Gonadotropin (hCG) is secreted by trophoblastic cells of placenta during early pregnancy. Its major functions include:

• Maintenance of corpus luteum
• Continued secretion of progesterone
• Maintenance of uterine endometrium

Since hCG is produced by placenta, this option is incorrect.

Step 2: Analyze option (B) Human Placental Lactogen (hPL).
Human Placental Lactogen (hPL) is another important placental hormone. It helps in:

• Altering maternal metabolism
• Ensuring nutrient supply to fetus
• Promoting mammary gland development

Thus, hPL is produced by placenta. Hence, this option is also incorrect.

Step 3: Analyze option (C) Estrogens.
During pregnancy, placenta secretes increasing amounts of estrogens. Functions of estrogens include:

• Growth of uterus
• Increased blood supply to reproductive organs
• Development of mammary glands
• Preparation for childbirth

Therefore, estrogens are also produced by placenta.

Step 4: Analyze option (D) Relaxin.
Relaxin is mainly secreted by the corpus luteum of ovary in humans. Its functions include:

• Relaxation of pelvic ligaments
• Softening of cervix
• Facilitation of childbirth

Although relaxin is associated with pregnancy, it is not considered a principal hormone secreted by placenta in standard NCERT classification. Therefore, Relaxin is the correct answer.

Step 5: Determine the final answer.
Among all the given hormones, Relaxin is not produced by placenta. Hence, the correct answer is: \[ \boxed{\text{Relaxin}} \]