INDOMETHACIN FAILS TO ALTER BASAL OR PHENOTHIAZINE-INDUCED PROLACTIN CONCENTRATIONS IN MAN

In order to evaluate the possible role of prostaglandins in pituitary prolactin (PRL) secretion, PRL was serially measured following perphenazine (Trilafon®) ingestion in 8 men before and after 5 days of indomethacin administration. Since estrogens have been shown to modulate prolactin secretion in man, serum steroids including estrone (E1), estradiol (E2), progesterone (P) and testosterone (T) were measured before and after indomethacin ingestion. Serum E1, P and T levels were similar during the pre- and post-indomethacin study periods: 56±4 (1 SEM) vs 48±5 pg/ml, 298±28 vs 315±32 pg/ml, and 8.1±0.7 vs 8.6±0.7 ng/ml, respectively. Serum E2 levels were slightly, but significantly, lower following indomethacin treatment at 30±3 vs 37±3 pg/ml (p<.01). Basal serum PRL concentrations were unaffected by indomethacin administration (9±3 pre- vs 8±2 ng/ml post-drug treatment). Integrated perphenazine-induced PRL responses were likewise similar during the 2 study periods: 101±16 ng.hr/ml during the control period and 104±14 ng.hr/ml following indomethacin. Thus, short-term indomethacin treatment had no effect on basal or perphenazine-stimulated PRL secretion in men.