Basic Fibroblast Growth Factor in the Adrenal Gland

Area of Science:

• Neuroscience
• Cell Biology

Background:

• Trophic factors are crucial for neuronal development and maintenance.
• Nerve growth factor (NGF) exemplifies trophic support from target organs to neurons.
• The concept of target organ-regulated neuronal maintenance implies retrograde trophic support.

Purpose of the Study:

• To investigate the role of basic fibroblast growth factor (bFGF) in retrograde trophic neuron-neuron interaction.
• To determine if bFGF is present in the adrenal medulla and supports autonomic spinal cord neurons.

Main Methods:

• Western blotting and immunostaining to detect bFGF in adrenal medulla extracts and chromaffin cells.
• Assessing the effect of a bFGF-specific antibody on adrenal medullary extract activity.
• Evaluating the mitogenic activity of chromaffin granule proteins on endothelial cells.
• Investigating the impact of adrenal medulla destruction and bFGF substitution on spinal cord neurons.

Main Results:

• Basic fibroblast growth factor (bFGF) or a related protein is present in the adrenal medulla and chromaffin cells.
• Antibodies against bFGF blocked trophic activity in adrenal medullary extracts, supporting neuron survival in vitro.
• Soluble proteins from chromaffin granules exhibited mitogenic activity on endothelial cells.
• Destruction of the adrenal medulla led to significant loss of spinal cord neurons, which was prevented by bFGF substitution.

Conclusions:

• Basic fibroblast growth factor (bFGF) is localized in chromaffin cells.
• bFGF maintains target-deprived autonomic spinal cord neurons, acting as an interneuronal trophic messenger in vivo.