Thyroid and Skin and Hair

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Topical triiodothyronine stimulates epidermal proliferation, dermal

thickening, and hair growth in mice and rats.

http://www.ncbi.nlm.nih.gov/entrez/query

fcgi?cmd=Retrieve&db=PubMed&list_uids=11525263&dopt=Abstract

Safer JD, Fraser LM, Ray S, Holick MF.

Department of Medicine, Boston University School of Medicine, Massachusetts

02118, USA. jsafer@...

The skin is a classic target tissue for thyroid hormone action. Although the

histology of skin in hypothyroid states is well documented, the literature

contains little assessment of skin in thyrotoxic states. In light of the

paucity of information on skin under the influence of excess thyroid hormone

we investigated the direct effect of thyroid hormone on skin.

Triiodothyronine (T3) was applied topically daily in liposomes to SKH-1

hairless mice for 7 days and to CD rats for 2 weeks. There was a

dose-dependent increase in epidermal proliferation, dermal thickening, and

hair growth in T3-treated animals. Mice that received 3.8 microg of T3 had

42% more hairs per millimeter than controls (p < 0.01), hair length that was

1,180% longer (p < 0.001), 49% greater epidermal 3H-thymidine incorporation

(p < 0.01), and 80% more 5-bromo-2'-deoxyuridine (BrdU) stained cells (p < 0

05). Rats receiving 12.8 microg T3 had 48% greater dermal thickness than

controls (p < 0.001), 26% greater epidermal thickness (p < 0.001), 85% more

hairs per millimeter (p < 0.005), and 130% greater 3H-thymidine

incorporation into the epidermis (p < 0.01). Thus, topically applied thyroid

hormone has dramatic effects on both skin and hair growth. These

observations offer a new strategy for developing thyroid hormone and its

analogues for treating disorders of skin and hair growth.

Thyroid-Adrenal Connection Information & Resources

http://www.bestweb.net/~om/thyroid