Blunting of neuroendocrine responses to infusion of L-tryptophan in women with perimenstrual mood change.

The neuroendocrine response to L-tryptophan infusion was measured at two stages of the menstrual cycle, premenstrually and postmenstrually, in 13 women with and 13 women without premenstrual depression (the MC and NMC groups respectively). Previous studies have shown that in non-depressed women, this challenge test results in an increase in circulating prolactin and growth hormone. In depressed women both responses are blunted. In this study the growth hormone and cortisol responses were smaller in the MC group than the NMC group on both occasions. The prolactin response was blunted premenstrually compared with postmenstrually in both groups. These findings suggest that women who experience premenstrual depression may have neuroendocrine abnormalities throughout the cycle. The neurotransmitter abnormalities reflected in these altered endocrine responses appear to interact with neuroendocrine changes that normally occur premenstrually resulting in a vulnerability to depression at that phase of the cycle.