Question: If only 25% of the pituitary gland remains after removal of a microadenoma for treatment of Cushing’s disease, is the gland still able to produce not only adequate amounts of hormone, but a normal amount as if the gland was intact? If so, does it take longer for the body to reach the optimal level of hormones when the pituitary is not whole?

Answer: In regards to the partial hypophysectomy, the remaining function depends on what part of the pituitary remains intact and what pituitary hormones have been affected. To determine that, it is useful to perform a combined pituitary function test using insulin-induced hypoglycemia and TRH to assess pituitary hormone response. There are circumstances in which much of the pituitary has been surgically removed and yet there is enough residual to maintain normal menstrual cycles and fertility. The response to stress depends on what has been the reason for the pituitary surgery. In cases of Cushing’s disease, if an ACTH-secreting pituitary microadenoma has been surgically removed, the normal corticotropes could be suppressed and the response to stress may be delayed for a long time. In the adult, growth hormone deficiency can develop with extensive pituitary surgery or radiation therapy and in the adult symptoms are not always easy to define. GH deficiency may promote increased deposition of fat, decreased physical stamina and endurance and sense of well being. Treatment with GH is not always sufficiently effective to justify daily injections and its cost. In children and adolescents, substitution with GH is certainly necessary for patients to achieve optimal linear growth.

By Dr. David Schteingart MD (Spring, 2009)