Up-regulation of adrenomedullin receptor gene expression in activated local stem cells during rat adrenal regeneration

作者：Rebuffat Piera; Macchi Carlo; Malendowicz Ludwik K; Nussdorfer Gastone G^*

来源：International Journal of Molecular Medicine, 2007, 20(6): 855-858.

• adrenomedullin
• adrenomedullin receptors
• gene expression
• adrenal regeneration
• rat

Previous studies showed that adrenomedullin (AM) gene expression was up-regulated in the regenerating rat adrenal cortex after enucleation and contra-lateral adrenalectomy, the effect being significant at day I after surgery and peaking between days 3 and 7. Using the same experimental model, we investigated by real time-polymerase chain reaction the mRNA expression of the AM receptor components: calcitonin receptor-like receptor (CRLR) and receptor activity-modifying proteins (RAMP)2 and 3. At time 0 (60 min after enucleation; control group), the CRLR mRNA content was similar to 2- and 5-fold higher than that of RAMP2 and RAMP(3), respectively. No significant changes in CRLR mRNA expression were observed in relation to the time elapsed from enucleation. RAMP(2) and RAMP(3) mRNAs did not exhibit significant changes at day 1 after surgery, but underwent a marked increase between days 3 and 7. The mRNA content of the two RAMPs decreased at days 14 and 28, although remaining significantly higher than that of the controls. These findings indicate that the AM receptor subtypes AM(1)-R (CRLR-RAMP(2)) and AM(2)-R (CRLR-RAMP(3)) are up-regulated in enucleated adrenals, and the hypothesis is advanced that this effect depends on the increased local production of AM. The concerted increase in AM and its receptor expression would greatly improve the autocrine-paracrine mechanism(s) by which AM favors proliferation of zona glomerulosa stem cells during adrenal regeneration.

• 出版日期2007-12