Hypophyseal function in the operative and postoperative phases after removal of pituitary tumours

In 47 patients with various pituitary tumours plasma cortisol, LH, FSH, prolactin, and GH were measured by radioimmunoassays to investigate anterior pituitary function. In 14 subjects LH--RH and TRH stimulation tests were performed to assess pituitary reserve before, during, and after surgical therapy. The mean cortisol levels were raised during and after the operative procedures until the 14th postoperative days. In patients with functionless tumours the other hormone concentrations remained nearly unchanged and in the normal ranges. After the removal of the tumour a rapid decrease in hormone levels, as might be expected, was rare, with the exception of the GH and prolactin levels in patients with hypersecretion. The postoperative stimulation tests showed a maintained secretory pituitary reserve due to active tissue left behind after operative removal of the tumour.