5-hydroxytryptamine signalling in irritable bowel syndrome with diarrhoea: effects of gender and menstrual status.
BACKGROUND
Symptomatology and physiology differ between men and women and across the menstrual cycle in irritable bowel syndrome (IBS). Ovarian hormones influence 5-hydroxytryptamine (5-HT), an amine known to play a role in gut motor-sensory function.


OBJECTIVE
To assess the effects of gender and menstrual status on platelet-depleted plasma (PDP) 5-HT concentration in IBS patients with diarrhoea (IBS-D) patients compared with healthy volunteers (HV).


METHODS
Platelet-depleted plasma 5-HT concentrations were assessed under fasting and fed conditions in 73 IBS-D patients (aged 18-58 years; 18 men) and 64 HV (aged 18-50 years; 24 men). Women were divided into those with low or high progesterone/oestrogen (P/O) levels.


RESULTS
Irritable bowel syndrome patients with diarrhoea had higher PDP 5-HT concentrations than HV under fasting (P = 0.002) and fed (P = 0.049) conditions. This was particularly related to IBS-D men having higher PDP 5-HT concentrations than healthy controls (P = 0.002). Moreover, PDP 5-HT concentrations in IBS-D women with low P/O levels were similar to healthy controls.


CONCLUSIONS
Similar to IBS-D women with high P/O levels, IBS-D men also have raised PDP 5-HT concentrations. 5-HT concentration normalizes at menses in IBS-D women, suggesting a shift in the mechanisms responsible for abnormal 5-HT signalling in these patients.
Houghton
L A
LA
Neurogastroenterology Unit, School of Translational Medicine-GI Sciences, University of Manchester, Wythenshawe Hospital, Manchester, UK. Lesley.Houghton@manchester.ac.uk
Brown
H
H
Atkinson
W
W
Morris
J
J
Fell
C
C
Whorwell
P J
PJ
Lockhart
S
S
Keevil
B
B
D000293:Adolescent; D000328:Adult; D001792:Blood Platelets / Q000378:metabolism*; D016022:Case-Control Studies; D003967:Diarrhea / Q000150:complications / Q000503:physiopathology*; D004435:Eating / Q000502:physiology; D004967:Estrogens / Q000378:metabolism; D005215:Fasting / Q000502:physiology; D005260:Female; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000150:complications / Q000503:physiopathology*; D008297:Male; D008597:Menstrual Cycle / Q000502:physiology*; D008875:Middle Aged; D011374:Progesterone / Q000378:metabolism; D012701:Serotonin / Q000378:metabolism*; D012737:Sex Factors; D015398:Signal Transduction / Q000502:physiology; D055815:Young Adult
D004967:Estrogens; D012701:Serotonin; D011374:Progesterone