The hormone responsible for ovulation is?

Appeared in: RUHS, Jaipur, PB B.Sc Nursing Entrance-2021

Explanation

Luteinizing Hormone (LH) is the primary hormone that directly triggers ovulation.
About two days before ovulation, a surge in LH secretion from the anterior pituitary gland occurs, increasing 6- to 10-fold.
This 'LH surge' is necessary for the final follicular growth and rupture, causing the release of the ovum from the ovary.
Without this preovulatory surge of LH, ovulation will not take place, even if FSH levels are high.

Option A: Follicle-Stimulating Hormone (FSH) is responsible for the growth and maturation of ovarian follicles at the beginning of the cycle, not the final release of the egg.
Option B: Testosterone is the primary male sex hormone. In females, it is produced in small amounts and acts as a precursor for estrogen but does not trigger ovulation.
Option C: Progesterone levels rise significantly after ovulation to prepare the uterine lining for pregnancy. It does not cause ovulation.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Hormonal regulation of ovulation as background academic context rather than a clinical decision trigger.
Nurses frequently educate patients on fertility awareness. Understanding that the LH surge precedes ovulation is the basis for using over-the-counter ovulation predictor kits, which detect this surge in urine.
Infertility treatments often involve hormonal manipulation. For instance, hCG, which mimics LH, may be administered to trigger ovulation in a controlled manner for procedures like IVF.
What if? If the LH surge fails to occur (a condition known as anovulation), the follicle may not rupture, and the egg is not released. This is a common cause of infertility, often seen in conditions like Polycystic Ovary Syndrome (PCOS).

How to Approach the Question

First, identify the keywords in the question: 'hormone' and 'ovulation'. This directs you to the topic of the female reproductive cycle.
This is a factual recall question. You need to access your knowledge about the specific functions of reproductive hormones.
Mentally review the sequence of the menstrual cycle: FSH stimulates follicle growth, leading to increased estrogen. High estrogen triggers an LH surge. The LH surge causes ovulation. After ovulation, the corpus luteum produces progesterone.
Based on this sequence, identify that the LH surge is the direct trigger for ovulation.
Evaluate and eliminate the other options based on their primary roles: FSH for follicular growth, Progesterone for post-ovulation endometrial support, and Testosterone as a primarily male hormone.

Concept Tested & Keywords

QuyCXTpuDGJNuW4jD2lTIi

E6 Physiology Guyton 4SAE Part 3 p. 35-37

E6 Pharmacology Katzung 16e p. 1049-1051

Practise the full RUHS, Jaipur, PB B.Sc Nursing Entrance-2021

Attempt every question from this paper in a timed mock, then review the full solution for each one.