Hyperprolactinaemia is associated with a higher prevalence of pituitary-adrenal dysfunction in non-functioning pituitary macroadenoma

Tjeerdsma G, Sluiter WJ, Hew JM, Molenaar WM, de Lange WE, Dullaart RPF. Hyperprolactinaemia is associated with a higher prevalence of pituitary—adrenal dysfunction in non-functioning pituitary macroadenoma. Eur J Endocrinol 1996;135:299—308. ISSN 0804–4643 In non-functioning pituitary macroadenoma (NFMA), hyperprolactinaemia (hyperPRL) is considered to be a sign of hypothalamic—pituitary dysregulation, but it is unknown whether hyperPRL is associated with an increased frequency of pituitary hormone deficiencies. Forty consecutive patients with histology-proven NFMA were studied and hyperPRL was defined as serum prolactin (PRL) >200 mIU/l in men and >600 mIU/l in women. The pituitary—adrenal axis was evaluated by measurement of urinary free cortisol (N = 38), peak cortisol to insulin-induced hypoglycaemia (IIH, N = 36) and to human corticotrophin-releasing hormone (hCRF, N = 40) and by urinary tetrahydro11-deoxycortisol (H4S, N = 39), plasma androstenedione increment (N = 39) and serum 11-deoxycortisol (N = 1) after metyrapone. Central hypothyroidism, gonadotrophin deficiency and growth hormone (GH) reserve were also assessed. Twenty patients had hyperPRL (serum PRL 331 (2231120)mIU/l (median, range) in men and 932 (660–3927)mIU/l in women); urinary free cortisol excretion (p < 0.03) and peak serum cortisol in response to IIH (p < 0.02) were lower in hyperPRL than in normoPRL patients; peak serum cortisol after hCRF was not different between groups but occurred later in hyperPRL patients (at 60 vs 30 min, p < 0.03); urinary H4S excretion and androstenedione response after metyrapone were lower in hyperPRL than in normoPRL patients (p < 0.05 for both); 60% of hyperPRL patients and 15% of normoPRL patients had an abnormal H4S response (p < 0.025); central hypothyroidism (overt + subclinical) was present in 74% of hyperPRL and in 60% of normoPRL patients (NS); 78% of hyperPRL and 55% of normoPRL patients had gonadotrophin deficiency (NS); growth hormone (GH) deficiency was present in 83% of hyperPRL and in 89% of normoPRL patients (NS); 73.3% of 75 evaluable pituitary hormone axes were abnormal in hyperPRL patients compared to 5 3.8% of 78 hormone axes in normoPRL patients (by metyrapone test to examine adrenal function, p < 0.025); and no significant differences in tumour grade and stage distribution were found between hyperPRL and normoPRL patients. It is concluded that hyperprolactinaemia in NFMA is associated with a higher prevalence of pituitary–adrenal dysfunction, which is likely to be explained at least in part by functional hypothalamic–pituitary interruption. RPF Dullaart. Department of Endocrinology, University Hospital Groningen, PO Box 30.001, 9700 RB Groningen, The Netherlands