Synthetic TRH (TRH-T) has recently been used for the treatment of chronic and acute neurologic disorders. We studied the effects of long-term (30 days) refracted daily intramuscular administration of 4 mg TRH-T on neuroendocrine and cardiovascular system and on glucose and fat metabolism in 22 patients (mean age 62.7 +/- 10.9) with chronic cerebrovascular disease. All subjects were submitted to ECG and arterial blood pressure determination and were assayed for TSH, thyroid hormone, PRL, glucose, creatinine, nitrogen, glutamine transaminase, cholesterol and triglycerides plasma levels before therapy (T0), after 30 treatment days (T30) and after a 15 days washout (T45). Thyroid hormone, TSH and PRL serum levels were detected also after 15 days of TRH-T therapy (T15). In addition, TSH and PRL response to 200 micrograms iv TRH was assessed at T0, T30 and T45. TRH-T administration did not cause significant alterations of neuroendocrine balance. Furthermore, we observed no changes in lipid metabolism, renal and liver function, arterial blood pressure, and ECG. In conclusion, TRH-T may be safely used in elderly patients with chronic cerebrovascular disease, independently to cardiovascular disorders.