Sex differences in plasma prolactin response to tryptophan in chronic fatigue syndrome patients with and without comorbid fibromyalgia.
BACKGROUND
Some think chronic fatigue syndrome (CFS) and fibromyalgia (FM) are variants of the same illness process. This would imply that CFS patients with and without comorbid FM have similar biological underpinnings. To test this, we compared serotonergic-based responses, plasma prolactin (PRL), and self-reported measures of fatigue to intravenous infusion of tryptophan among patients with CFS alone, CFS + FM, and healthy controls.


METHODS
Men and women with CFS alone or CFS + FM and healthy subjects, none with current major depressive disorder (MDD), were given 120 mg of L-tryptophan per kg lean body mass intravenously (i.v.). Before and after tryptophan infusion, blood samples were collected, and plasma PRL, tryptophan, and kynurenine concentrations were determined.


RESULTS
Women with CFS alone, but not CFS + FM, showed upregulated plasma PRL responses compared with controls. There were no differences among groups of men. Plasma tryptophan and kynurenine concentrations did not differ among groups.


CONCLUSIONS
These results indicate that women with CFS alone have upregulated serotonergic tone that is not seen in those with comorbid FM. The lack of effect in men suggests a mechanism that might explain, in part, the increased prevalence of CFS in women. The data support the interpretation that CFS in women is a different illness from FM.
Weaver
Shelley A
SA
Department of Neurology & Neurosciences, UMDNJ-New Jersey Medical School, Newark, New Jersey, USA.
Janal
Malvin N
MN
Aktan
Nadine
N
Ottenweller
John E
JE
Natelson
Benjamin H
BH
D000328:Adult; D018687:Antidepressive Agents, Second-Generation / Q000008:administration & dosage*; D016022:Case-Control Studies; D015673:Fatigue Syndrome, Chronic / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011388:Prolactin / Q000097:blood*; D012727:Sex Characteristics; D014364:Tryptophan / Q000008:administration & dosage*
D018687:Antidepressive Agents, Second-Generation; D014364:Tryptophan; D011388:Prolactin
Clin Chem. 1997 Dec;43(12):2424-6
9439467
J Affect Disord. 1995 Aug 18;34(4):283-9
8550954
Adv Exp Med Biol. 1991;294:369-76
1772075
Curr Top Med Chem. 2006;6(18):1987-96
17017969
Neuropsychopharmacology. 2004 May;29(5):833-46
14997175
Eur J Clin Nutr. 1998 Jun;52(6):425-30
9683395
Psychol Med. 2001 May;31(4):585-91
11352361
Psychopharmacology (Berl). 2004 Mar;172(2):137-44
14647968
BMJ. 1992 Apr 18;304(6833):1010-2
1586780
Can J Psychiatry. 1995 Mar;40(2):93-6
7788624
Biol Psychiatry. 2005 Feb 1;57(3):239-46
15691524
Pain. 1978 Jun;5(1):65-71
307724
J Clin Psychiatry. 1982 Dec;43(12 Pt 2):11-8
6130068
J Rheumatol. 1992 Jan;19(1):90-4
1556707
J Affect Disord. 2003 Jun;75(1):77-82
12781354
J Rheumatol Suppl. 1989 Nov;19:158-63
2607510
J Nutr. 2006 Feb;136(2):553S-559S
16424146
Life Sci. 1976 Apr 1;18(7):707-14
131230
Psychosom Med. 2003 Mar-Apr;65(2):268-75
12651994
Clin Endocrinol (Oxf). 1998 Jan;48(1):31-7
9509065
Amino Acids. 2001;20(1):25-34
11310928
Clin Chem. 2002 Mar;48(3):579-81
11861457
Arthritis Rheum. 1990 Feb;33(2):160-72
2306288
Biol Psychiatry. 1995 Feb 15;37(4):245-52
7711161
Ann Intern Med. 1994 Dec 15;121(12):953-9
7978722
Am J Clin Nutr. 1985 Aug;42(2):366-70
4025206
J Neurochem. 1981 Aug;37(2):410-7
6167678
Adv Exp Med Biol. 1999;467:697-704
10721121
Psychopharmacol Bull. 1984 Summer;20(3):595-8
6473667
J Neurochem. 1968 Oct;15(10):1093-108
5304606
J Affect Disord. 1996 Nov 4;41(1):71-6
8938208
Clin Sci (Lond). 2003 Aug;105(2):213-8
12708966
BMJ. 1997 Jul 19;315(7101):164-5
9251547
Clin Infect Dis. 1995 Nov;21(5):1204-10
8589144
Arthritis Rheum. 1992 May;35(5):550-6
1374252
Eur J Pharmacol. 1999 Jun 30;375(1-3):87-100
10443567
Lancet. 2006 Jan 28;367(9507):346-55
16443043
Am J Clin Nutr. 2000 Aug;72(2 Suppl):573S-8S
10919962
J Pharmacol Sci. 2006 Jun;101(2):107-17
16766858
Psychosom Med. 2003 Sep-Oct;65(5):889-95
14508037
Arch Intern Med. 1999 Oct 11;159(18):2129-37
10527290
Rheumatology (Oxford). 2001 Mar;40(3):290-6
11285376
Ann Intern Med. 1999 Jun 1;130(11):910-21
10375340
Psychol Med. 2001 Nov;31(8):1331-45
11722149