Growth hormone releasing factor in human cerebrospinal fluid

Area of Science:

• Neuroendocrinology
• Biochemistry

Background:

• Growth hormone releasing factor (GHRF) plays a crucial role in regulating growth hormone secretion.
• Understanding GHRF levels in cerebrospinal fluid (CSF) is important for neurological and endocrine research.

Purpose of the Study:

• To quantify GHRF levels in human CSF.
• To investigate the stability and characteristics of GHRF in CSF.
• To explore the relationship between CSF GHRF and body weight, as well as the effect of lithium treatment.

Main Methods:

• Radioimmunoassay (RIA) was used to measure GHRF concentrations in CSF from healthy volunteers and bipolar patients.
• High-performance liquid chromatography (HPLC) was employed to characterize the forms of GHRF in CSF.
• Sequential CSF sampling was performed to assess temporal stability and gradients.

Main Results:

• Mean CSF GHRF levels in healthy volunteers were 23.4 +/- 7.2 pg/ml.
• CSF GHRF levels demonstrated stability over time and no rostro-caudal gradient, suggesting a long half-life.
• A significant negative correlation was observed between CSF GHRF and body weight.
• No significant differences in CSF GHRF levels were found between healthy volunteers and lithium-treated bipolar patients, nor were any effects of lithium noted.

Conclusions:

• CSF GHRF is present in healthy humans and exhibits stability, supporting its potential role as a stable biomarker.
• Body weight is a significant factor influencing CSF GHRF levels.
• Lithium treatment does not appear to alter CSF GHRF levels in euthymic bipolar patients.