Background. Sumatriptan, a specific agonist at 5-HT1D
receptors, stimulates release of growth
hormone (GH) and inhibits release of prolactin (PRL).
Methods. We gave sumatriptan (6 mg subcutaneously) to 11 patients
with unipolar major depression and 11 control subjects matched for age,
sex, weight and menstrual cycle phase. Serum
GH and PRL were measured at 0, 15, 30, 45, 60 and 90 min after injection.
Results. The maximal rise in GH was significantly reduced in
the depressed patients, with 60%
showing no increase over baseline compared with 18% of controls. There
were no significant
differences in PRL responses.
Conclusions. These results suggest reduced sensitivity of
5-HT1D receptors in major depression. Our
results and those of studies investigating 5-HT1A receptors
imply that both 5-HT1A and 5-HT1D
autoreceptors may show reduced function in major depression.