CSF and plasma somatostatin levels in acromegaly

Cerebrospinal fluid (CSF) and plasma levels of somatostatin have been measured in patients with active acromegaly and the results compared to those obtained in patients with non-endocrine diseases. Plasma levels have also been studied in acromegalics given oral glucose. The mean CSF somatostatin level in twenty patients without endocrine disease was 76 pg/ml (range 46-112) which did not differ significantly from that found in eight acromegalics (mean 87 pg/ml, range 48-160). Plasma somatostatin in twenty-two acromegalic patients on no medical treatment was 43 pg/ml (range 9-113), not significantly different from values in a normal control population. There were no differences in the somatostatin levels of non-diabetic acromegalics. After oral glucose, there was a rise in circulating somatostatin in eleven out of twelve acromegalic patients, and this rise did not differ from that seen in normal subjects. It is probable that altered somatostatin secretion is neither the cause nor the result of acromegaly; however it is possible that local changes in somatostatin concentration which are not reflected in peripheral plasma or CSF levels may occur near the site of its production.