GH1 and hypopituitarism: While no significant postoperative changes in FT4 were observed in our study, this may be explained by the combined effect of a substantial postoperative decrease in GH that promotes increased FT4 secretion and intraoperative manipulation of the pituitary or the associated stress response, both of which have been shown in previous studies to suppress FT4 secretion or even cause pituitary insufficiency [17–19].