To elucidate the depaminergic control of T.S.H. secretion, we analized the pattern of T.S.H. secretion in seven normal controls and nine primary hypothyroid subjects, before and after single or combined administration of specific dopaminergic,receptor blocker, metoclopramide, and specific depaminergic receptor stimulant, bromergocryptine(CB-154). The results obtained were as follows: 1) There was a significant rise in T.S.H. levels after intra venous injection of metocloramide (10mg) in hypothyroid subjects. But there was no significant rise in T.S.H. levels in normal controls. The T.S.H. response to metoclopramide varied considerably, being large in mild cases and small in severely hypothyroid subjects. 2) There was a significant fall in T.S.H. levels after oral administration of bromergocryptine (2mg) in hypothyroid subjects, but there was no significant fall in T.S.H. levels in normal controls. 3) There was no significant fluctuation in T.S.H. levels after combined administration of both metoclopramide and bromergocrytine. 4) There was no significant fluctuation in T.S.H. levels after intravenous injection of normal saline(2ml) in both hypothyroid and normal subjects. 5) There was no significant change in serum $T_3;and;T_4$ after administration of metoclopramide and and bromergocryptine respectively and serially. These data support the fact that there is a dopaminergic control in the secretion of T.S.H. in the human.