[Comparative studies of growth hormone secretion in acromegaly after isolated and combined application of insulin hypoglycemia, LH-RH- and TRH tests (author's transl)]

Normal growth hormone secretion is rare after microsurgical normalization of growth hormone levels in acromegaly

The effect of microsurgery on growth hormone (GH) secretion was studied in 34 patients with acromegaly. All patients showed enlarged sella volumes according to encephalography and macroadenomas at surgery. Preoperative GH levels were elevated in all 34 patients and 14 had concomitant hyperprolactinemia. There was a correlation between basal GH levels and sella size. Visual field defects, suprasellar extension, long duration of the disease, hyperprolactinemia and aneuploidy were noted in patients with low as well as high levels of GH preoperatively. The average reduction of GH levels in the total series was 71 +/- 21% (mean +/- SD). A notably similar reduction of GH levels was seen regardless of preoperative GH levels, concomitant hyperprolactinemia, visual field defects, size of the adenoma, invasive growth or increasing experience of the surgeon. Therefore, normal GH levels after surgery were reached mainly in patients with moderate GH increments preoperatively. GH levels were normalized by surgery in 15 patients but only four of these showed normal GH response to TRH and iota-dopa tests. Thus, only four patients (12%) fulfilled these criteria for cure of GH homeostasis.

Treatment of acromegaly by trans-sphenoidal operation, 90-yttrium implantation and bromocriptine: results in 230 patients

Two hundred and thirty patients with acromegaly were diagnosed and treated in a prospective cooperative study in twelve university clinics. Primary treatment was: trans-sphenoidal surgery (152 patients), trans-sphenoidal surgery with additional cryotherapy (eighteen patients), Yttrium-90-implantation (thirty patients), bromocriptine (thirty patients). The results of endocrine assessment before treatment and 6 months after operation, 90-Y implantation or commencement of bromocriptine therapy are reported. The best results (low GH, no or little deterioration of pituitary function, low complication rate) were achieved by trans-sphenoidal surgery, especially in patients with intrasellar tumours (basal GH less than 5 ng/ml in 59.7%). Results were less good with increasing tumour size. Additional cryosurgery was accompanied by a high rate of anterior pituitary insufficiency and is no longer employed. Yttrium-90-implantation resulted in less improvement in GH levels (basal GH less than 5 ng/ml in 51.7% of patients with intrasellar tumours), a high rate of pituitary insufficiency and more complications. Bromocriptine treatment was least effective in lowering GH concentrations (basal GH less than 5 ng/ml in 33% of patients with intrasellar tumours). Different criteria for treatment success were compared. In the entire group, basal GH concentrations below 5 ng/ml were attained in 51.7% of all patients whose values were higher than this prior to treatment. Suppressibility of GH below 2 ng/ml during glucose loading occurred in only 34.9%. An abnormal GH response to TRH/LHRH was present in 47.2% before and in 43.4% after/during treatment. The prognostic significance of this latter finding must be evaluated by further study.