Question

Hormones secreted by the placenta to maintain pregnancy are
A) hCG, hPL, progestogen, estrogens
B) hCG, hPL, progestogen, prolactin
C) hCG, progestogens, estrogens, glucocorticoids
D) hCG, hPL, estrogens, relaxin, oxytocin

Answer 1

Hint: Placenta also acts as an endocrine tissue and produces several hormones required for the maintenance of pregnancy. hCG, hPL and relaxin are produced to maintain a physiological environment between the mother and the baby.

Complete answer:
Placentation is the formation of the placenta which occurs as an adaptation to intrauterine development. Due to very little yolk present in mammalian eggs, the embryo depends on the mother for nourishment and oxygen supply. Thus, a temporary organ formed by the maternal tissue and extraembryonic membranes called placenta develops and helps in the physiological exchange between mother and the fetus. Though placenta is a characteristic feature of mammals, it is present in Peripatus, Salpa, Mustelus and certain lizards.
Many hormones are secreted by the placenta like hCG, progesterone, estrogens and human placental lactogen. Lactogen mobilizes fat from the adipose tissue for the production of milk. hCG is important as it protects the fetus from allograft rejection by the uterus due to immunological reaction. Its presence in urine is an indicator of pregnancy and is used for the pregnancy test. Progesterone enables the uterus to retain pregnancy and prevents spontaneous abortion of the fetus. Estrogen helps in breast and uterus enlargement. Fetal growth is promoted by placental lactogen. In the later period of pregnancy, a hormone called relaxin is likewise produced by the ovary and placenta.

So, the correct answer is option A.

Note: Prolactin is synthesized and secreted by the anterior pituitary gland, whereas oxytocin is produced by the hypothalamus and stored in the posterior pituitary. The level of several hormones is increased several fold during pregnancy in the mother’s blood.