Glycosylated and non-glycosylated prolactin forms are increased after opioid administration as part of surgical anaesthesia.
OBJECTIVE
Previous studies have shown that non-glycosylated prolactin (NG-PRL) increased more markedly than glycosylated hormone (G-PRL) after TRH or metoclopramide stimulation. The aim of the present study was to determine whether such results could be extended to opioid-induced PRL stimulation.


METHODS
Open and prospective study. Using a newly developed IRMA specific for NG-PRL, we determined G-PRL and NG-PRL immunoreactivities after administration of 0.8-1.2 mg of the opioid drug phenoperidine as part of an anaesthesia.


METHODS
Ten male patients anaesthetized for surgical treatment of a prolapsed lumbar intervertebral disc.


METHODS
Samples were obtained hourly pre and post-operatively, and every 15 minutes during operation for determination of plasma PRL, NG-PRL and G-PRL. Plasma cortisol, ACTH and GH levels were measured in an attempt to differentiate the respective roles of stress and opiate 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 after drug administration. The proportion of G-PRL immunoreactivity was not significantly different when basal (25.2%) and stimulated (27%) values were compared (P > 0.05), and when mean increments of NG-PRL and G-PRL were compared (345 and 348%, respectively). The opioid drug induced a significant decrease in cortisol levels after injection and during operation (from 585 +/- 63 to 99 +/- 51 nmol/l) with a concomitant decrease in ACTH levels. GH levels were not significantly altered during anaesthesia but were significantly greater (P < 0.05) after than before surgery (5.0 +/- 1.3 vs 0.98 +/- 0.54 mU/l, respectively).


CONCLUSIONS
We conclude from the present and from previous data that opioid induced anaesthesia is accompanied by an increase in both glycosylated and non-glycosylated PRL and that different PRL secretagogues may induce distinct responses in terms of PRL molecular forms.
Priou
A
A
Department of Endocrinology, Hôpital Nord, Marseilles, France.
Bruder
N
N
Bégou
D
D
Morange
I
I
Graziani
N
N
Grisoli
F
F
Brue
T
T
D000328:Adult; D000768:Anesthesia, General; D006031:Glycosylation; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D015592:Immunoradiometric Assay; D008297:Male; D010638:Phenoperidine / Q000494:pharmacology*; D011388:Prolactin / Q000031:analogs & derivatives* / Q000097:blood*; D011446:Prospective Studies; D013268:Stimulation, Chemical; D013312:Stress, Physiological / Q000097:blood; D013514:Surgical Procedures, Operative
C043928:prolactin, glycosylated; D011388:Prolactin; D010638:Phenoperidine; D006854:Hydrocortisone