Effects of dexamethasone on the availability of L-tryptophan and on the insulin and FFA concentrations in unipolar depressed patients.
Several authors have shown that the availability of L-tryptophan (L-TRP) in the serum is lower in patients with major depression than in controls. It has recently been reported that the administration of a dose of dexamethasone sufficient to cause cortisol suppression also caused significant decrements in the availability of L-TRP. In order to elucidate the putative pathophysiological mechanisms underlying this decreased L-TRP disposition, the authors examined 37 depressed women categorized according to the DSM-III. L-TRP, the sum of five competing amino acids (CAA), the L-TRP/CAA ratio, and insulin and free fatty acid (FFA) levels were determined both before and after oral administration of 1 mg dexamethasone. The availability of L-TRP was significantly lower in depressed women with melancholia compared with simple major and minor depressives. The baseline disposal of L-TRP was related neither to insulin nor to FFA concentrations Dexamethasone administration significantly reduced the L-TRP and L-TRP/CAA values and increased FFA and insulin levels. Postdexamethasone L-TRP and FFA levels were significantly and positively correlated.
Maes
M
M
Psychiatric Center, St-Jozef, Belgium.
Jacobs
M P
MP
Suy
E
E
Vandewoude
M
M
Minner
B
B
Raus
J
J
D000275:Adjustment Disorders / Q000097:blood / Q000175:diagnosis*; D000328:Adult; D001921:Brain / Q000378:metabolism; D003866:Depressive Disorder / Q000097:blood / Q000175:diagnosis* / Q000523:psychology; D003907:Dexamethasone / Q000493:pharmacokinetics; D005230:Fatty Acids, Nonesterified / Q000097:blood*; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D007328:Insulin / Q000097:blood*; D008875:Middle Aged; D011446:Prospective Studies; D011618:Psychotic Disorders / Q000097:blood / Q000175:diagnosis*; D014364:Tryptophan / Q000097:blood*
D005230:Fatty Acids, Nonesterified; D007328:Insulin; D003907:Dexamethasone; D014364:Tryptophan; D006854:Hydrocortisone