Effects of clonidine on blood pressure, noradrenaline, cortisol, growth hormone, and prolactin plasma levels in high and low intestinal tone depressed patients.

Systolic blood pressure (SBP), diastolic blood pressure (DBP), norepinephrine (NE) plasma levels, cortisol (CRT), growth hormone (GH), and prolactin (PRL) plasma levels were investigated in 26 high intestinal tone (high-IT) and 24 low intestinal tone (low-IT) depressed patients, before and after the intramuscular injection of clonidine (2.5 micrograms/kg). A positive correlation was found between NE, DBP, and Hamilton Depression Rating Scale (HRS) values in low-IT depressed patients, while a negative correlation was found between HRS/IT and NE in high-IT depressed patients. Although clonidine induced significant reduction of SBP in both groups, the drug reduced DBP and NE in the low-IT group, only. CRT mean level was greater in the high-IT than in the low-IT depressed group. However, clonidine was unable to induce changes in CRT, GH, and PRL mean levels in any depressed group. Our results suggest that the clonidine-induced DBP reduction is a reliable index of sympathetic activity in depressed patients and that both parameters (DBP and IT) are useful physiological markers to differentiate two types of depressive syndromes.