Blockage of ghrelin-induced prolactin secretion in women by bromocriptine.
OBJECTIVE
To investigate the effect of bromocriptine on ghrelin-induced PRL secretion in women.


METHODS
Longitudinal study.


METHODS
University hospital.


METHODS
Ten healthy, normally cycling women.


METHODS
The women were injected IV on day 3 of three cycles with a single dose of normal saline (cycle 1) or ghrelin (1 microg/kg) after pretreatment for 2 days either with placebo (cycle 2) or with bromocriptine (cycle 3) per os. Blood samples were taken before and frequently after drugs administration for 120 minutes.


METHODS
The PRL and GH responses to ghrelin were assessed.


RESULTS
Bromocriptine suppressed basal PRL levels significantly. The injection of ghrelin stimulated a significant increase in serum PRL levels in cycle 2 but not in cycle 3, in which PRL levels remained stable. The response of GH to gherlin was significantly attenuated in cycle 3 as compared with cycle 2.


CONCLUSIONS
The present study demonstrates for the first time that bromocriptine blocked the stimulating effect of ghrelin on PRL release and attenuated the GH response to the same stimulus. The mechanism of these interactions needs to be clarified.
Department of Obstetrics and Gynecology, Medical School, University of Thessalia, Larissa, Greece.
Christina I
CI
Messini
Department of Obstetrics and Gynecology, Medical School, University of Thessalia, Larissa, Greece.
Konstantinos
K
Dafopoulos
Department of Obstetrics and Gynecology, Medical School, University of Thessalia, Larissa, Greece.
Nektarios
N
Chalvatzas
Department of Nuclear Medicine, Medical School, University of Thessalia, Larissa, Greece.
Panagiotis
P
Georgoulias
Department of Obstetrics and Gynecology, Medical School, University of Thessalia, Larissa, Greece.
George
G
Anifandis
Department of Obstetrics and Gynecology, Medical School, University of Thessalia, Larissa, Greece. Electronic address: messinis@med.uth.gr.
Ioannis E
IE
Messinis
D000328:Adult; D001971:Bromocriptine / Q000494:pharmacology*; D015536:Down-Regulation / Q000187:drug effects; D004958:Estradiol / Q000097:blood; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D054439:Ghrelin / Q000008:administration & dosage / Q000037:antagonists & inhibitors* / Q000097:blood / Q000494:pharmacology*; D006727:Hormone Antagonists / Q000494:pharmacology; D006801:Humans; D007986:Luteinizing Hormone / Q000097:blood; D008597:Menstrual Cycle / Q000187:drug effects / Q000502:physiology; D010919:Placebos; D011374:Progesterone / Q000097:blood; D011388:Prolactin / Q000097:blood / Q000378:metabolism*; D013997:Time Factors; D055815:Young Adult
D054439:Ghrelin; D006727:Hormone Antagonists; D010919:Placebos; D001971:Bromocriptine; D011374:Progesterone; D004958:Estradiol; D011388:Prolactin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone