Which hormone stimulates ovulation in females?

Luteinising hormone (LH) plays a crucial role in the female reproductive system, particularly in the regulation of the menstrual cycle and ovulation. LH is secreted by the anterior pituitary gland and is responsible for triggering ovulation, which is the release of a mature egg from the ovary.

As the menstrual cycle progresses, a surge in LH levels typically occurs around the midpoint, leading to the final maturation of the follicle and the subsequent release of the egg. This surge is prompted by rising estrogen levels from developing follicles, which signal the pituitary gland to release LH.

In contrast, while follicle-stimulating hormone (FSH) is involved in the initial stages of follicle development, it is LH that directly stimulates the ovulatory process. Progesterone, secreted primarily by the corpus luteum after ovulation, is involved in preparing the uterus for potential pregnancy but does not stimulate ovulation itself. Thyroxine (T4) is a thyroid hormone that regulates metabolism and energy but is not directly involved in the reproductive hormone pathway.

Thus, LH's specific role in triggering ovulation is what makes it the correct answer to the question.