Prolactinomas are the most frequent pituitary tumors and may co-secrete GH (growth hormone). IGF-1 (insulin-like growth factor-1) is the main responsible for GH actions and a parameter for the diagnosis of acromegaly. With the objective of identifying through a IGF-1 levels analysis, in the initial evaluation of prolactinoma patients, the existence of mixed tumors [GH and prolactin (PRL)], we studied 7 men and 27 women, aged between 19 and 72 years, confronting them with the results of basal and glucose stimulated (glucose tolerance test - GTT) GH levels, indicated when GH >0.4 ng/mL or IGF-1 levels were elevated. The prevalence of patients with GH >0.4 ng/mL and elevated IGF-1 was higher than expected; however, after GTT, no patient fulfilled the diagnostic criteria for acromegaly. However, we suggest that, they should be submitted to IGF-1 evaluation, due to the risk of GH co-secretion in prolactinomas. Special attention should be paid to those who present a significant decrease of PRL levels without concomitant tumor size reduction.
insulin-like growth factor-1; hyperprolactinemia; prolactinoma; acromegaly
