The pleiotropic effects of excessive luteinizing hormone secretion in transgenic mice.

Luteinizing hormone (LH) is member of the glycoprotein hormone family of gonadotropins, which also includes the highly related human chorionic gonadotropin and follicle-stimulating hormone. The necessity of these factors for sustaining human fertility has been known for decades. In addition, elevated serum levels of LH have been associated with polycystic ovarian syndrome, suggesting that the appropriate balance of LH is critical for maintaining reproductive function. To dissect the biological consequences of aberrant LH signaling in vivo, several genetically engineered mouse models have been developed that overexpress LH or have increased LH signaling. These models underscore the importance of tightly regulated LH levels for normal reproductive function, and reveal novel roles for LH and gonadal hormones in tumorigenesis of multiple tissues, including the ovary, mammary gland, and pituitary. Thus, mice with altered LH signaling provide valuable tools in understanding normal reproduction and various pathological conditions.