Controlled study on the diurnal variation of neuroendocrine rhythm in depressed patients

Objective To study the function and diurnal variation of hypothalamic-pituitary-adrenal (HPA) axis and hypothalamic-pituitary-thyroid(HPT) axis,and the relationship with clinical characteristics of di-urnal rhythm in depressed patients. Methods Forty-nine depressed patients met diagnostic DSM-Ⅳ criteria and thirty-eight normal controls were collected. The plasma levels of cortisol (CORT), adrenocorticotropic hormone (ACTH), T3, T4, thyroid-stimulating hormone (TSH) at 7 am and 7 pm were measured by radioimmunoassay, then the results concemed were compared among the depressed groups with and without diurnal variation and control group by multivariate analysis of variance. Results The plasma level of morning CORT, morning and evening TSH ((365.94±120.78) nmol/L; (6.24±2.47)μIU/ml; (6.68±2.42)μIU/ml; respectively) were respective-ly higher than those of control group((284.91±83.39) nmol/L; (3.82±1.75)μIU/ml;(4.01±1.69)μIU/ ml, P<0.05). The plasma levels of morning and evening T4 were significantly lower than those of control group(P <0.05). The CORT morning-evening difference variable distinguished between depressed and control group (P< 0.001),but no significant differences could be found between the depressed groups with and without diurnal varia-tion. There were no significant differences in the CORT, T3, T4, TSH morning-evening difference variable between various clinical subtypes of depressed patient (unipolar/bipolar; psychotic/nonpsychotic). Conclusion Abnormal CORT morning-evening difference variable was observed in the depressed patients compared with normal controls,and may be used as a special trait mark of depressed group. Key words: Depressive disorders ;  Diurnal rhythm ;  HPA axis ;  HPT axis ;