Vitamin D3 dramatically stimulated the hair growth

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Endocrinology 2002 Nov;143(11):4389-96 Related Articles, Links
Vitamin D3 analogs stimulate hair growth in nude mice.
Vegesna V, O'Kelly J, Uskokovic M, Said J, Lemp N, Saitoh T, Ikezoe T,
Binderup L, Koeffler HP.
Cedars-Sinai Medical Center/University of California Los Angeles School
of Medicine, Los Angeles, California 90048, USA.
The active form of vitamin D3 can regulate epidermal keratinization by
inducing terminal differentiation; and mice lacking the vitamin D
receptor display defects leading to postnatal alopecia. These
observations implicate the vitamin D3 pathway in regulation of hair
growth. We tested the ability of 1,25 dihydroxyvitamin D3 and its
synthetic analogs to stimulate hair growth in biege/nude/xid (BNX) nu/nu
(nude) mice exhibiting congenital alopecia. Nude mice were treated with
different vitamin D3 analogs at doses that we had previously found to be
the highest dose without inducing toxicity (hypercalcemia). The mice
were monitored for hair growth and were scored according to a defined
scale. Skin samples were taken for histological observation of hair
follicles and for extraction of RNA and protein. Vitamin D3 analogs
dramatically stimulated the hair growth of nude mice, although parental
1,25 dihydroxyvitamin D3 had no effect. Hair growth occurred in a
cyclical pattern, accompanied by formation of normal hair follicles and
increased expression of certain keratins (Ha7, Ha8, and Hb3).
* Vitamin D3 analogs seem to act on keratinocytes to initiate hair
follicle cycling and stimulate hair growth in mice that otherwise do not
grow hair.*

 

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Biphasic effect of 1,25-dihydroxyvitamin D3 on human hair follicle growth and hair fiber production in whole-organ cultures.

Harmon CS, Nevins TD.

Preclinical Dermatology Research, Hoffmann-La Roche, Nutley, New Jersey 07110.

We have used a whole-organ culture system to investigate the effects of 1,25(OH)2D3 on human hair follicle growth and hair fiber production. Relatively low concentrations (1-10 nM) of 1,25(OH)2D3 stimulated the cumulative growth of hair follicles and hair fibers, by 52% and 36%, respectively (concentration producing 50% of the maximal response values of 0.3 nM). The initial rates of follicle and fiber growth were increased, whereas the respective growth periods were unaffected. At higher concentrations of 1,25(OH)2D3, there was a dose-dependent inhibition of both follicle and fiber growth (IC50 values of 100 nM), in part due to reduction in the growth periods. There was a marked delay between the onset of 1,25(OH)2D-induced hair follicle and hair fiber growth inhibition. Incubation of hair follicles with 100 nM 1,25(OH)2D3 resulted in a rapid, transient inhibition of DNA synthesis (55% inhibition at 24 h), followed by a gradual return to control levels at day 4. Prolonged (> 5 h), incubation in the presence of 100 nM of 1,25 (OH)2D3 was required for follicle growth inhibition to be manifest. Ro 31-7549, a selective inhibitor of protein kinase C, did not prevent 1,25(OH)2D3-induced inhibition of hair follicle growth. These data suggest that 1,25(OH)2D3 may play a physiologic role in maintaining optimal hair follicle activity, and that elevation of 1,25(OH)2D3 may inhibit hair growth in vivo.

 

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nude mice

have pics

 

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