Endocrine Abstracts

Introduction: There are high levels of anterior pituitary hormones in the cerebrospinal fluid (CSF), i.e. beyond the blood–brain barrier, in many patients with pituitary tumors.

Aim: To assess the influence of CSF pituitary hormones on brain functions reflected by sleep architecture and sleep apnea.

Method: Twenty-nine patients (17 women, 12 men) with pituitary adenomas (20 acromegaly, 5 nonfunctioning pituitary adenomas, 4 prolactinomas) were subjected to overnight polysomnography and serum and CSF sample collections. Correlations between CSF concentrations of GH, PRL, FSH, LH and sleep variables were analyzed, adjusting the results for the effect of serum concentrations. In a control group of 41 cases without endocrine diseases the CSF levels of hormones were also measured. The study was approved by the local ethical committee.

Results: GH level in the CSF was significantly and positively correlated with the mean duration of central apnea episodes (Spearman test P=0.02). The mean duration of central apnea was significantly higher in patients with high CSF GH than in those with normal CSF GH (Mann–Whitney U test P=0.014). CSF FSH showed significant correlation with the obstructive apnea index (Spearman, P=0.03). Serum GH was significantly correlated with the index of REM-related apnea (Spearman, P=0.008). The other pituitary hormones investigated did not show an effect upon sleep apnea. None of the pituitary hormones analyzed in serum and CSF significantly influenced the sleep stages or sleep latencies.

Conclusion: Among the pituitary hormones, GH and FSH influence the brain functions, as reflected by the sleep events, after crossing the blood–brain barrier.