Table 2.

Summary of the arguments in favor or against a local synthesis of ghrelin in brain.

Level	Experimental Findings	Main Conclusions
pre-proghrelin mRNA	No signal by Northern blot or ISHH. Positive signal by RT-PCR or Q-PCR.	Pre-proghrelin mRNA measurable in low amounts
Ghrelin peptide	Presence of ghrelin in amounts less than 100- to 5000-fold as compared to stomach levels	Ghrelin measurable in minute amounts but no conclusive evidence for local synthesis.
Cellular localization.	Presence of ghrelin-IR positive neurons in many nuclei and regions	No reproducibility amongst studies. Lack of adequate specificity controls, namely absence in ghrelin KO mice. Cellular location of the positive signal unexpected, based on the epitope recognized by the antibodies.