The goal of this prospective study is to analyse the hormonal components in the blood of patients that were diagnosed with empty sella. Hereby we only take the hormones into consideration that are produced by the pituitary gland and/or are influenced by it due to positive/negative feedback. These are GH, ACTH, TSH, FSH, LH, PRL, oxytocine, ADH but also IGF-1, estradiol, testosteron, F4 and cortisol. The purpose is to see if abnormalities of the blook levels can be explained by the absence/shrinking of the pituitary gland. During this study, there will be a blood draw twice. The reason is to avoid wrong positive and negative results. Together with the second blood draw, there will be an insuline tolerance test in all patients. MRI will only be done if the last taken image is more than two years old or if the MRI was not taken with main focus on the pituitary gland.

Inclusion Criteria:

• Patients that were diagnosed with an (partial) empty sella detected by MRI or CT of the brain have been included in this study. Whenever the MRI or CT scan was performed more than two years ago, a new MRI scan was required.

Exclusion Criteria:

• Children (patients less than 18 years) and patients with earlier diagnosed carcinomas of the brain as well as patients with secondary empty sella (antecedents of radiation, pharmacological treatment of pituitary adenomas, traumatic head injury and surgery of the pituitary gland as well as the central nervous system) were not included.