Authors:K. Imamura, A. Bonfils, A. Diani, and H. Uno. Wisconsin Primate Research
Center, Univ. Wisconsin, Madison, WI, USA, Hoechst Marion Roussel,
Romainvill, France, and Pharmacia-Upjohn, Kalamazoo, MI, USA.
“Our previous studies demonstrated that the treatment with either RU58841 (RU) or minoxidil (M) alone induced significant hair regrowth in the bald stumptail macaques. However, the rate of hair growth has not significantly progressed after 6 months.
This implies that M stimulates follicular cell proliferation but is unable to halt androgenetic follicular regression. On the contrary, RU prevents androgenetic follicular regression but appears to have no direct stimulating effect on follicular cell growth.
“The present study was aimed to evaluate the effect of combined RU 5% (RU-5) with M 2% (M-2) or M 5% (M-5) solution on hair regrowth by both photographic recording and micromorphometrical analysis of follicular growth (folliculogram). The vehicle, mixture of propylene glycol, alcohol, and water, was used for both compounds and was applied to the placebo group.
Each group has 3 monkeys. The data of hair growth for RU-5, M-2, and M-5 groups were used the results from our previous studies. The results revealed that the initial hair regrowth was noticed as early as 1 month after treatment in RU-5 + M-5 and 2 months in RU-5 + M-2 group.
The similar degree of hair growth noticed at 3 months after treatment with RU-5 and M-5 alone.
In M-2 group, the hairiness maintained but showed no noticeableregrowth. At 3 months, regrowth of long terminal hairs appeared in both RU-5 + M-2 and RU-5 + M-5 groups and these hairs maintained for 6 to 12 months.
The overall rate of anagen conversion conversion and follicular enlargement were higher in combined groups compared to RU-5 and M-5 alone and revealed no significant difference between RU-5 + M-2 and RU-5 + M-5.
The follicular growth was not found in M-2 group. Progressive effect of hair growth by combined treatment of antiandrogen with hypertrichotic agent showed most remarkably in early stage, but within one year the overall effects of hair regrowth revealed no significant difference compared to the rate in RU-5 or M-5 alone.
Long-term observation will be necessary to find the synergetic effects on the follicular growth.”