How can the pituitary gland function when parts of it breakdown?

Pituitary hormones: It is possible that some pituitary hormones do not work, and others do work. For example, after a pituitary insult (tumor, trauma, etc), you could lose the gonadotropins (fsh, lh), but still have preserved acth and TSH (adrenal and thyroid). Some of this is related to the pituitary anatomy, and the locations of certain populations of cells.