Spermidine treatment down-regulates ODC expression in the HF.

<p><b>A.</b> Immunoreactivity of ODC in the proximal HF demonstrates moderate ODC expression in the matrix keratinocytes, and strong expression in the proximal companion layer. <b>B.</b> Spermidine treatment for 6d decreased ODC immunoreactivity in the lower doses (0.1 and 0.5 µM). Columns represent means±SEM; n = 9–13 HFs/group <b>C.</b> By Q-PCR, spermidine treatment for 24 h slightly decreased the <i>ODC</i> transcript steady-state levels in human anagen HF mRNA extracts, compared to <i>PPIA,</i> although this did not reach significances. <b>D.</b> However, spermidine significantly down regulated <i>ODC</i> transcription in cultured human ORS keratinocytes after 48 h. *<i>P</i><0.05. Columns represent means±SEM. Results represent triplicate determinations of samples. Total RNA was pooled from 20 HFs. DP, dermal papilla; MK, matrix keratinocytes; ORS, outer root sheath.