Authors:
Kyung-Ho Kim, Yong-Jun Piao Ki-Beom Suhr, Jeung-Hoon Lee, Jang-Kyu Park Department of Dermatology, Chungnam National University College of Medicine, Daejeon, Korea.
Study Information and Results:
The dermal papilla (DP) plays a central role in follicle development and cycle control. Its role is mediated by many factors including growth factors. It is now generally believed to be the actual site of androgens passing appropriate messages to the epithelial cells, possibly in the form of growth factors.
Androgens may stimulate Dermal Papilla cells to produce androgen-dependent diffusible growth factors, such as IGF-1, HGF, bFGF, KGF, TGF-B 1, 2, which act not only on the DP cells themselves, but also stimulate follicular epithelial cells. In this investigation we have designed to find out whether Dermal Papilla cells secrete growth factors like IGF-1, and the effect of androgens on their expression of the above growth factors using reverse northern hybridization.
We also tried to determine whether several growth factors gene expression by cultured DP cells was affected by concentration of testosterone propionate using RT-PCR.
We here reported:
1) The effect of androgen on the expression of these growth factors, each of the genes for these were confirmed to be expressed in the control Dermal Papilla cells which were not treated with testosterone as well as in the 10 -8 M testosterone-treated cells. However, other conditions were the same except length or CG contents of each probe, but KGF, bFGF, TGF-B 1 was highly expressed factors among those factors tested.
2) The expression of IGF-1 was increased by testosterone propionate in a concentration-dependent manner, with a maximal effect at 10 -8 M, but other growth factors mRNA expression was unaffected by the additional of testosterone propionate.
These studies, therefore, report that several specific molecules such as IGF-1 that are synthesized by DP cells and whose production is regulated by androgen at the transcriptional level might mediate the action of androgen to miniaturize hair follicles. The androgen-induced upregulation of the expression of IGF-1 might be one of the plausible mechanisms that lead to androgenic alopecia.
