GLYCOSYLATED AND NONGLYCOSYLATED PROLACTIN FORMS ARE INCREASED AFTER OPIOID ADMINISTRATION AS PART OF SURGICAL ANESTHESIA

OBJECTIVE Previous studies have shown that nonglycosylated prolactin ( NG-PRL) increased more markedly than glycosylated hormone (G-PRL) afte r TRH or metoclopramide stimulation. The aim of the present study was to determine whether such results could be extended to opioid-induced PRL stimulation. DESIGN Open and prospective study. Using a newly deve loped IRMA specific for NG-PRL, we determined G-PRL and MG-PRL immunor eactivities after administration of 0.8-1.2 mg of the opioid drug phen operidine as part of an anaesthesia. PATIENTS Ten male patients anaest hetized for surgical treatment of a prolapsed lumbar intervertebral di sc. MEASUREMENTS Samples were obtained hourly pre and post-operatively , and every 15 minutes during operation for determination of plasma PR L, NG-PRL and G-PRL. Plasma cortisol, ACTH and GH levels were measured in an attempt to differentiate the respective roles of stress and opi ate agonists in the variations of PRL levels during surgery. RESULTS A dramatic increase in PRL levels was observed in all patients from an average of 300 +/- 90 to 1200 +/- 330 mU/l (mean + SEM) 30 minutes aft er drug administration. The proportion of G-PRL immunoreactivity was n ot significantly different when basal (25.2%) and stimulated (27%) val ues were compared (P > 0.05), and when mean increments of NG-PRL and G -PRL were compared (345 and 348%, respectively), The opioid drug induc ed a significant decrease in cortisol levels after injection and durin g operation (from 585 +/- 63 to 99 +/- 51 nmol/l) with a concomitant d ecrease in ACTH levels. GH levels were not significantly altered durin g anaesthesia but were significantly greater (P < 0.05) after than bef ore surgery (5.0 +/- 1.3 vs 0.98 +/- 0.54 mU/l, respectively). CONCLUS IONS We conclude from the present and from previous data that opioid i nduced anaesthesia is accompanied by an increase in both glycosylated and non-glycosylated PRL and that different PRL secretagogues may indu ce distinct responses in terms of PRL molecular forms.