Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Pituitary Tumors ?
    ### Response:
    Your pituitary gland is a pea-sized gland at the base of your brain. The pituitary is the "master control gland" - it makes hormones that affect growth and the functions of other glands in the body.     Pituitary tumors are common, but often they don't cause health problems.
    