FIGURE 6:

Molecular bases for ADAM17/TGFα induction of severe parathyroid hyperplasia in SHPT and its suppression by vitamin D. TGFα induction of ADAM17-gene transcription reinforces the vicious autocrine loop of enhanced ADAM17 release of TGFα and TGFα activation of the EGFR to induce LIP-driven growth exacerbation and ADAM17-gene transcription in A431 cells and in rat and human SH. 1,25-dihydroxyvitamin D efficacy to enhance C/EBPβ synthesis contributes to inhibit ADAM17-gene expression. 25D enhances 1,25-dihydroxy vitamin D actions induction of C/EBPβ to suppress ADAM17-gene expression.