Optometry Admission Test (OAT) Practice

What is the primary function of progesterone?

1. Stimulates T lymphocyte development

2. Promotes growth of endometrium

3. Maintains circadian rhythms

4. Involved in osmoregulation

The correct answer is: Promotes growth of endometrium

The primary function of progesterone is indeed to promote the growth of the endometrium. This hormone is crucial during the menstrual cycle, specifically during the luteal phase, following ovulation. After ovulation, the corpus luteum forms and secretes progesterone, which prepares the endometrial lining for potential implantation of a fertilized egg. If pregnancy occurs, progesterone levels remain elevated to maintain the endometrium and support early pregnancy. This function is vital for reproductive health, making it a key player in ensuring that the uterine lining is thick and nutrient-rich, providing the necessary environment for a fertilized egg to implant and develop. If implantation does not occur, progesterone levels drop, leading to the shedding of the endometrium and the start of menstruation. In contrast, the other options address functions that are not primarily associated with progesterone. For instance, the stimulation of T lymphocyte development relates more to thymosin and other immune-related hormones, while maintenance of circadian rhythms is closely related to hormones like melatonin. Osmoregulation is managed largely by hormones such as aldosterone and antidiuretic hormone (ADH), rather than progesterone. Thus, the promotion of endometrial growth is the definitive