Acquired prolactin deficiency indicates severe hypopituitarism in patients with disease of the hypothalamic-pituitary axis

Summary objective Prolactin deficiency has been the subject of many scientific studies, but there is a paucity of information regarding prolactin deficiency in humans. In this report, adults with disease of the hypothalamic–pituitary axis (HPA) were studied to determine the prevalence of severe acquired prolactin deficiency (APD) and the pathophysiological characteristics associated with it. patients and methods APD was defined as a serum prolactin level persistently below the detection limit of the assay, i.e. less than 50 mU/l (normal range: male 85–444, female 85–530). Patients with a diagnosis of acromegaly, prolactinoma or with congenital or drug induced prolactin deficiency were excluded. Three hundred and sixty‐nine patients (190 women, age range 17–79 years) with disease of the HPA, meeting the specified criteria were identified. results Twenty‐two (13 women, age range 29–76 years), showed evidence of APD. Thirteen of the 22 patients with APD had been treated for Cushing's disease. In all, 62 patients treated for Cushing's disease were identified, resulting in a prevalence of APD in treated Cushing's disease of 20·97%. Excluding treated Cushing's disease, the prevalence of APD in the remainder of the cohort was 2·93%. Nineteen patients with APD (86·4%) and 183 without APD (52·7%) underwent surgery in the region of the HPA (P = 0·0042). In contrast, nine patients with APD (40·9%) and 283 without APD (80·4%) had received radiotherapy, with fields which included the HPA (P