All these diverse efficacies of NL-hGH
seem to indicate that somehow the skin
stem cells of the bulge or transiently amplifying
progenitor cells derived from
the bulge stem cells in the hair follicle
(Fig. 11), are influenced by the presence
of exogenous hGH and involved in the
pharmaceutical and cosmetic outcomes
of the topical NL-hGH application. Based
on this rationale, we further examined
whether hair (follicle) number or the hair
growth cycle of the mouse is affected by
the application of NL-hGH, using minoxidil
as a positive control. Mice were treated
for 2 weeks with NL-hGH after depilation
and before peritoneal BrdU injection
and subsequently sacrificed 3 hrs
after the injection. The results clearly
showed that NL-hGH application on the
back of the mouse increased not only the
hair number but potentially the hair
length and thickness. As, in a given hair
bulb, a more number of actively proliferating hair matrix cells is correlated
with longer duration of anagen phase,
thus with longer and thicker hair (17).
Minoxidil influenced on the hair number
as well, but not the hair length or thickness.
These results are summarized in
Fig. 12. Therefore NL-hGH was superior
to minoxidil in increasing both the hair
number and possibly the hair length and
thickness in the mouse experiments.