Retinol vitamin keratinization

Vitamin A-deficient experimental animals fail to grow adults are blind and sterile, with testicular degeneration in males and keratinization of the uterine epithelium in females. Although deficient female animals wUl conceive, and the fetuses will implant, formation of the placenta is impaired and the fetuses are resorbed. Epithelia in general are hyperplastic and keratinized, and there is impaired cellular immunity with increased susceptibility to infection. Both retinol and retinoic acid are required for gestation in the rat in deficient animals, retinoic acid alone will not prevent fetal resorption after about day 10 of gestation (WeUik and DeLuca, 1995 WeUik et al., 1997). 

Epidermal keratinization and mucous membrane squamous metaplasia respond to both oral and topical vitamin A therapy. Vitamin A exists in three forms retinol, retinal, and retinoic acid.VitaminA increases the mucous production of goblet cells and perhaps the aqueous and lipid components of the tears as well. Tretinoin is a normal metabolite and the carboxylic form of retinol. Retinol is present in tears and the lacrimal gland appears to be its major provider. Retinoic acid has been shown to be effective in ocular surfece disorders such as squamous metaplasia by reversing the corneal and conjunctival keratinization and improving epithelium wound healing rate. 

Case Study 5 Isotretinoin (13-aT-retinoic acid, 22, Scheme 23.8) belongs to a family of vitamin A (retinol)-related compounds. It inhibits sebaceous gland function and keratinization and is used for the treatment of dermatological diseases such as acne. It is extremely effective in very severe and nodulocystic acne and prevents scarring. More recently, isotretinoin has been evaluated for its potential use in certain cancerous conditions. 

Keratinization Reduction in the production of mucus of epithelial cells, particularly in the conjunctiva and cornea of the eye due to vitamin A or retinol deficiency. 

---