Dopaminergic regulation of BDNF content in the pituitary intermediate lobe

Previous studies in adult rats have demonstrated that the neurotrophin, brain-derived neurotrophic factor (BDNF), is present in virtually all cells of the pituitary intermediate lobe. In the present study, we demonstrate that cells cultured from adult intermediate lobe pituitary (ILP) rapidly lose their BDNF immunoreactivity (IR). Furthermore, a similar loss of immunostaining occurs in whole (undissociated) ILP within 30 min after removal from the rat. However, when the dopamine agonist apomorphine is present throughout the dissociation procedure and during cultivation, BDNF-IR is preserved. Supplying apomorphine only during either dissociation or cultivation did not prevent the loss of BDNF-IR in the 24 h cultures. These results suggest that a tonic dopaminergic stimulus is required to maintain BDNF-IR in ILP cells.