Which of the following sets of hormones regulate menstrual cycle ?

Question

UnlockIAS · Accepted Answer

Correct — option (1), FSH, LH, estrogen and progesterone. The human menstrual cycle runs on the hypothalamic-pituitary-ovarian axis, and these four hormones are the complete working set that drives it phase by phase. Pulsatile GnRH from the hypothalamus makes the anterior pituitary release two gonadotropins, follicle-stimulating hormone (FSH) and luteinising hormone (LH). Early in the cycle, rising FSH recruits a cohort of ovarian follicles and drives one dominant follicle to mature; the maturing follicle's granulosa cells secrete estrogen, which thickens and proliferates the uterine endometrium (the proliferative phase) and, once it peaks, feeds back on the pituitary to trigger a sharp mid-cycle LH surge. That LH surge is what actually causes ovulation — the rupture of the follicle and release of the egg — and it also converts the ruptured follicle into the corpus luteum. The corpus luteum then secretes progesterone (along with some estrogen) through the luteal phase, converting the endometrium into a secretory, implantation-ready lining. If fertilisation does not occur, the corpus luteum degenerates, progesterone and estrogen levels collapse, and the unsupported endometrium sheds as menstrual flow, after which FSH begins rising again to start the next cycle. Every other option in this question either substitutes an unrelated steroid hormone for one of these four or drops a hormone the cycle cannot run without, which is why only option (1) names the actual regulating set.

Why the other options are wrong — (b) This set keeps LH and estrogen but swaps in two hormones from the wrong axes altogether. Testosterone is the principal androgen of the male reproductive system, produced mainly by the testes under LH stimulation there; while females do produce small amounts of testosterone from the ovary and adrenal cortex, it is not a driver of the follicular-to-luteal hormonal sequence of the menstrual cycle. Corticosterone is a glucocorticoid made by the adrenal cortex as part of the hypothalamic-pituitary-adrenal stress axis, regulating metabolism and, in some species, mineral balance — it has no role in ovulation or endometrial cycling. The set is also missing FSH entirely, without which follicles are never recruited or matured in the first place.  (c) Three of these four are genuine cycle hormones, but cortisol does not belong among them. Cortisol is the body's principal glucocorticoid, released by the adrenal cortex under ACTH control as part of the stress-response HPA axis; it influences metabolism, immune function and blood pressure, not follicular development or ovulation. More importantly, this set has no LH at all — without the mid-cycle LH surge, ovulation never happens and the corpus luteum never forms, so a set that keeps FSH, estrogen and progesterone but drops LH still cannot regulate the complete cycle.  (d) Dihydrotestosterone (DHT) is a potent androgen formed by the enzymatic conversion of testosterone, responsible for male secondary sexual characteristics such as facial hair, prostate growth and pattern baldness — it plays no regulatory role in the female reproductive cycle. As with option (3), this set also lacks LH, so even setting DHT aside, the remaining three hormones (FSH, estrogen, progesterone) cannot by themselves produce ovulation, since the LH surge is the specific trigger for follicle rupture and corpus luteum formation.

Concept: The menstrual cycle is jointly an ovarian cycle and a uterine cycle, synchronised by the same four hormones acting in sequence. The hypothalamus sets the pace with pulsatile GnRH; the anterior pituitary translates that into FSH and LH; and the ovary translates the gonadotropins into the two steroid hormones, estrogen and progesterone, that actually remodel the uterus. In the follicular phase, rising FSH matures a dominant follicle, which secretes estrogen; estrogen builds up the endometrium (proliferative phase) and, at a critical threshold, flips from suppressing to stimulating the pituitary, producing the LH surge. Ovulation follows roughly a day after the LH peak. In the luteal phase, the corpus luteum's progesterone converts the endometrium into a secretory lining capable of supporting implantation, while also suppressing further GnRH/FSH/LH release so a new follicular wave cannot start mid-cycle. Without fertilisation and the rescue signal of hCG, the corpus luteum has a fixed lifespan of about two weeks, after which hormone levels fall and menstruation begins the next cycle.

State PCS 2025 Q61 — Science & Technology PYQ with Answer

State PCS 2025 Q61 — Science & Technology PYQ with Answer