Singh, R., Pretheeban, T. and Rajamahendran, R. 2011. GnRH agonist (buserelin)-induced in vitro apoptosis in bovine endometrium. Can. J. Anim. Sci. 91: 265-273. Apoptosis is a vital physiological process. The local modulatory role of the GnRH, GnRH-R system in uterine physiology is not clear. We investigated GnRH agonist (buserelin)-induced apoptosis in bovine endometrium. Reproductive tracts were collected from a local abattoir. The endometrial explants were sliced into smaller pieces, cultured for 20 h and then treated (6 h) with buserelin (0, 200, 500, 1000 ng mL^-1), the GnRH antagonist-antide (500 ng mL^-1) and antide buserelin (500 200 ng mL^-1), and stored at -80°C for RNA extraction. Two micrograms of total RNA was subjected to reverse transcription-polymerase chain reaction using gene-specific primers. Subsequently, endometrial epithelial cells were isolated from the follicular and luteal phase uteri, cultured for 48 h, characterized and treated with buserelin (200 ng mL^-1), antide (500 ng mL^-1), and antide buserelin (500 200 ng mL^-1) for 6 h. The cells were stained with acridine orange-ethidium bromide and visualized and counted under a fluorescent microscope. Buserelin up-regulated BAX (200 ng mL^-1) and CASPASE3 mRNA (200 and 500 ng mL^-1) and induced apoptosis (200 ng mL^-1) at the cellular level in the follicular phase endometrium. GnRH appears to regulate uterine homeostasis in bovine endometrium at the transcriptional and cellular levels.