Table 1. Expression of selected differential genes (PZ-old versus PZ-young) coding for extracellular paracrine mediators. Changes are displayed as fold change from the microarray and were verified by Q-PCR.

		Fold change
Gene symbol	Gene description	Microarray	Q-PCR
FGF5	Fibroblast growth factor 5	13.4	2.2
HGF	Hepatocyte growth factor	12.8	9.6
IGF2	Insulin-like growth factor 2	6.6	9.4
IGFBP4	Insulin-like growth factor-binding protein 4	2.1	7.1
IGFBP5	Insulin-like growth factor-binding protein 5	13.6	21.3
MMP1	Matrix metallopeptidase 1	4.5	6.8
SOD2	Superoxide dismutase 2	6.5	5.5

Abbreviations: PZ, peripheral zone; Q-PCR, quantitative PCR.