TITLE:
Role of the ACTH/MC2R System in the Hair Cycle in Mice
AUTHORS:
Keiichi Hiramoto, Kumi Orita, Yurika Yamate, Emiko Kasahara
KEYWORDS:
MC2R-/- Mice, Adrenocorticotropin Hormone, Corticosterone, Period Circadian Clock 1, Cyclic Guanosine Monophosphate
JOURNAL NAME:
Journal of Biosciences and Medicines,
Vol.4 No.7,
June
24,
2016
ABSTRACT: Adrenocorticotropin
hormone (ACTH), which is secreted in response to psychological stress, plays an
important role in the hair cycle. This study examined the mechanism by which
ACTH affects the hair cycle using mice deficient in melanocortin
receptor-2(MC2R-/-), which is a main receptor for ACTH. We observed
the hair cycle using female MC2R-/- mice at 15 weeks old and five
days old to determine whether there were any age-dependent differences. The
15-week-old MC2R-/- mice showed the anagen phase for all mice. On
the other hand, all of the MC2R+/+ mice showed the telogen phase at
the same age. Moreover, in the five-day-old mice, the hair growth of the MC2R-/- mice occurred earlier than in the MC2R+/+ mice. Both the 15-week-old
and five-day-old MC2R-/- mice had higher levels of ACTH and alpha-melanocyte
stimulating hormone in the blood than did the MC2R+/+ mice. In
addition, in the 15-week-old MC2R-/- mice, the hair cycle shifted to
the telogen phase following the administration of a cyclic guanosine
monophosphate (cGMP) inhibitor and MC1R/MC5R inhibitor. In the five-day-old
MC2R-/- mice, the hair growth was slowed by the administration of
corticosterone. These results suggest that the ACTH/MC2R system has an important
role in the hair cycle.