A combined anterior pituitary stimulation test: experience with 285 individuals

A pituitary reserve test was performed in 285 individuals. Eighteen were healthy volunteers without any endocrine disease, 25 suffered from a presumed hypothalamic abnormality, 22 from hypopituitarism, 10 from acromegaly, 65 from the amenorrhea-galactorrhea syndrome, 2 from Nelson's syndrome, 32 from borderline primary hypothyroidism, 15 from borderline hyperthyroidism, 20 were on chronic levothyroxine therapy for primary hypothyroidism, and 15 had severe uncorrected primary hypothyroidism. Sixteen postmenopausal women were also included, as well as 15 patients with idiopathic ovarian failure and six with ovarian dysgenesis. Twelve male patients with hypergonadotropic and 12 with hypogonadotropic hypogonadism were also examined.The pituitary reserve test consisted of intravenous administration of a mixture of the thyrotropin-releasing hormone (TRH), gonadotropin-releasing hormone (GnRH), and regular insulin. The following tests were obtained prior to the injection only (time 0): serum thyroxine (T(4)), tri-iodothyronine (T(3)), T(3) resin uptake or thyroxine-binding globulin, total and free testosterone in men, estradiol and progesterone in women, and sex hormone binding globulin. At times 0, 20, 30, and 60 minutes, serum concentrations of the following compounds were obtained: glucose, adrenocorticotropic hormone, cortisol, growth hormone, prolactin, thyroid-stimulating hormone, luteinizing hormone, and follicle-stimulating hormone.Normal responses were established in a large number of cases. More or less typical patterns were demonstrated in the above-listed disease categories. Poor correlations between basal and stimulated values were observed, which emphasizes the diagnostic importance of the stimulation test. Maximum data were obtained using a combined test that has negligible morbidity, may be performed within an hour in an outpatient setting, and which examines the anterior pituitary function in a comprehensive fashion.