LH, or luteinizing hormone, is a hormone produced by the anterior pituitary gland in the brain. It plays a crucial role in regulating the reproductive system in both males and females. In women, LH triggers ovulation and helps maintain the menstrual cycle, while in men, it stimulates the production of testosterone. LH levels fluctuate throughout the menstrual cycle, peaking just before ovulation. Abnormal levels of LH can indicate various health issues, such as polycystic ovary syndrome (PCOS) in women or hormonal imbalances in men. Monitoring LH can be important for fertility assessments and overall reproductive health.