Heterogeneity of prolactin responses to oestradiol benzoate in women with prolactinomas.
Serum prolactin concentrations were measured for 72 h after intramuscular injection of 1 mg of oestradiol benzoate in six normoprolactinaemic women and nineteen with a prolactinoma (eleven with an obviously enlarged pituitary fossa and eight with a normal pituitary fossa). The group with an obvious tumour showed a rise in mean serum prolactin at 48 h to 122% of basal concentrations (p less than 0.05), and at 72 h to 137% of basal concentrations (p less than 0.01). Individual responses were variable, but in four patients serum prolactin rose to 165% or more of basal concentrations. In the group with a prolactinoma and a normal pituitary fossa serum prolactin at 72 h was 121% of basal concentrations (p less than 0.05). Normoprolactinaemic women showed no significant change in serum prolactin at any time. This study demonstrated a heterogeneity of serum prolactin responses to acute oestradiol administration in women with prolactinomas. Some patients with large tumours had a hypersensitive response to oestradiol. This heterogeneity of response could account for the present unpredictability of expansion of prolactinomas during pregnancy.
D000293:Adolescent; D000328:Adult; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D006801:Humans; D010911:Pituitary Neoplasms / Q000378:metabolism*; D011247:Pregnancy; D011388:Prolactin / Q000097:blood* / Q000378:metabolism; D011458:Prostaglandins E / Q000097:blood; D012306:Risk; D012636:Secretory Rate / Q000187:drug effects
D011458:Prostaglandins E; D004958:Estradiol; D011388:Prolactin