Healthy male volunteers injected subcutaneously with 200 mg L-GABOB showed no significant changes in plasma GH, prolactin and cortisol levels. On the other hand, an intrathecal injection of 300 mg D, L-GABOB to cerebrovascular patients caused significant increases in plasma GH, prolactin and cortisol levels at 60 min after injection. These results indicate that GABOB may elicit the secretion of GH, prolactin and ACTH via the central nervous system.