Expression of interleukin-6 (IL-6) and IL-6 receptor mRNAs in rat adrenal medulla

Using in situ hybridization and reverse transcription combined with the polymerase chain reaction (RT-PCR) we have studied the expression and developmental regulation of interleukin-6 (IL-6) and its receptor mRNAs in rat adrenal medulla. Labeling for both transcripts was much more intense over the adrenal medulla than over cortical regions at postnatal day 70. Levels of mRNAs of both genes measured by RT-PCR increased from birth to adulthood. In vitro survival and neurite growth of chromaffin cells from early postnatal rats were not affected by IL-6. Even so, the presence and developmental regulation of IL-6 and its receptor are consistent with a possible auto- or paracrine role of IL-6 in rat adrenal medulla.