Ovulation typically occurs when which hormone reaches its peak in most animals?

Ovulation is primarily triggered by a surge in luteinizing hormone (LH). This surge is typically preceded by a rise in estrogen levels, which occurs during the follicular phase of the estrous cycle. As the follicle matures, it produces increasing amounts of estrogen, leading to a positive feedback mechanism that results in a rapid increase in LH release from the pituitary gland. This peak in LH is what ultimately induces ovulation, causing the mature ovarian follicle to release an egg.

Understanding the role of LH is crucial, as it is specifically responsible for initiating ovulation after reaching a threshold concentration, distinguishing it from other hormones. For example, while estrogen and follicle-stimulating hormone (FSH) play significant roles in reproductive processes, they do not directly trigger the ovulatory event. Prolactin, on the other hand, is primarily involved in lactation and does not influence the timing of ovulation. Thus, recognizing the specific functions and timing of these hormones is key to understanding how ovulation is regulated in most animals.