The pattern of growth hormone secretion during the menstrual cycle in normal and depressed women

Objective Major depression is associated to altered hypothalamic-pituitary function. Stress is linked to elevated cortisol as well as menstrual cycle disturbance; however, there is no known relationship between depression and menstrual cycle disruption. The aim of this study was to investigate changes of growth hormone (GH) secretion during the menstrual cycle in normal and depressed women. Design Case-control study. Patients and methods Nineteen women affected with depression and 24 normal controls were included. The two groups had comparable body mass index (BMI), and age (29.4 +/- 9.8 vs. 28.6 +/- 9.7 years). Nine depressed and 10 controls were studied in the follicular phase, while 10 depressed and 14 controls were studied in the luteal phase of the cycle. GH was sampled every 10 min for 24 h, and the data were analysed by the cluster pulse detection method. Results There was no difference in 24-h mean GH concentrations between depressed and control subjects (P = 0.93), even after accounting for menstrual cycle phase (P = 0.38). GH pulse frequency was higher during the follicular phase of the cycle (P = 0.032), and nocturnal GH was higher in the follicular phase of the cycle (P = 0.05, and after adjusting for 24-h GH, P = 0.0138) regardless of whether the subjects were depressed or healthy. Conclusions In studies of GH secretion in women with or without depression, it is necessary to control for the phase of menstrual cycle.