Distribution of growth hormone and thyroid-stimulating hormone in cerebrospinal fluid and pathological compartments of the central nervous system

Abstract

Human growth hormone (HGH) radio-immunoassay (RIA) was adapted for an accurate measurement of immunoreactive HGH concentrations in the CSF in different cases of hypothalamic-somatotropin dysfunctions. In control subjects ( n = 43) mean HGH levels were 0.35 ± 0.03 ng/ml in CSF and 1.95 ± 0.2 ng/ml in plasma with a CSF plasma ratio of 17%. The thyroid-stimulating hormone (TSH) RIA gave in controls mean basal levels of 2.65 ± 0.2 μU/ml in CSF and 5.95 ± 0.3 μU/ml in plasma with a CSF plasma ratio of 44%. HGH and TSH concentrations in CSF and plasma show a very good correlation; but the regression curves for both hormones are distinctly different and appear specific for each polypeptide hormone. Hypothalamic-somatotropin hyperreactivity was reported in diabetic retinopathy (DR). CSF and plasma HGH concentrations in a group of diabetic patients with progressing retinopathy ( n = 27) were not different from those in normal subjects (respectively 0.35 ± 0.05 in CSF and 2.10 ± 0.25 ng/ml in plasma with a CSF plasma ratio of 16%). The HGH regression curve obtained in diabetics is similar to that of controls. These data do not substantiate the hypothesis of an HGH hyperreactivity in diabetic retinopathy. In somatotropin hypersecretion (acromegaly) without adenoma suprasellar extension, higher HGH concentrations recorded in CSF than in plasma cannot be attributed to an anatomical break-down of the CSF blood-brain barrier and suggest an active transport process of pituitary hormones to the CNS. HGH and TSH concentrations were measured in the cystic fluid of CNS tumors. In 1 case of a cystic dysembryoma, the HGH and TSH of CF were considerably increased. In gliomas ( n = 8) the HGH and TSH cystic fluid concentrations were more elevated (respectively 0.72 ± 0.2 ng/ml and 3.6 ± 0.7 μU/ml) than in the CSF of controls.