Stanniocalcin (STC) is a new mammalian polypeptide hormone and appears to be a regulator of neuronal function. We have already shown that the induction of STC mRNA and protein expression by cAMP is integral to neuroblastoma cell differentiation, particularly neurite outgrowth. In this study, we examined the cAMP pathway in greater detail. Some common neuritogenic agents, euxanthone (PW1) and trans-retinoic acid (RA), were studied for possible interactions with the dbcAMP-mediated response. Our results showed that STC mRNA induction by dbcAMP was mediated by PKA-CREB pathway, accompanied with phosphorylation of CREB and a reduction of p50, p65 and p-IB levels. Using a synthetic peptide NF-B SN50, stimulation of dbcAMP-mediated STC expression was observed; indicating the nuclear translocation of NF-B might possibly repress STC expression. Dibutyryl cAMP-induced STC mRNA expression was enhanced by PW1. In contrast, RA had highly suppressive effects. Co-treatment of cell with PW1 and cAMP provoked an increase in pCREB. Conversely, cotreatment with RA suppressed pCREB. The results highlighted the importance of phosphorylation of CREB in mediating STC gene expression. Taking a step further to dissect the possible regulatory pathways involved, with the aid of phorbol 12-myristate 13-acetate (PMA) or ionomycin, additive effects on STC gene expression were observed. The induction was aided by further elevation of pCREB, which was completely abolished by Gö 6976, a Ca²⁺-dependent PKC and PKC₁ inhibitor. Our results indicated that cross-talk with PKC and/or Ca²⁺ signaling pathways might sensitize cAMP-mediated effects, on CREB phosphorylation and STC gene expression.