Hormonal regulation of hair follicles exhibits a biological paradox
April 2007
in “Seminars in Cell & Developmental Biology”
TLDR Androgens can both stimulate and cause hair loss, and understanding their effects is key to treating hair disorders.
The document from 2007 examines the paradoxical effects of androgens on hair follicles, where they can stimulate hair growth in certain body areas while causing balding on the scalp. It discusses the role of hormones in hair growth cycles, with a study of 14 men showing seasonal variations in hair growth. The paper also explores how pregnancy hormones affect hair growth, with an increase in anagen phase during the second and third trimesters. The document emphasizes the importance of genetics in androgen-dependent hair growth, noting variations in the androgen receptor gene in balding men. It describes the current model of androgen action, where androgens act on dermal papilla cells, altering gene expression and affecting hair characteristics. The paper concludes that understanding the specific factors altered by androgens is crucial for developing treatments for hair disorders and provides insights into other androgen-dependent conditions.
View this study on sciencedirect.com →
Cited in this study
research Genetic basis of skin appendage development
Hair, teeth, and mammary glands develop similarly at first but use different genes later.
research Differences in Expression of Specific Biomarkers Distinguish Human Beard from Scalp Dermal Papilla Cells
Beard and scalp hair cells have different gene expressions, which may affect beard growth characteristics.
research Human Scalp Hair Follicles Are Both a Target and a Source of Prolactin, which Serves as an Autocrine and/or Paracrine Promoter of Apoptosis-Driven Hair Follicle Regression
Prolactin contributes to hair loss by promoting hair follicle shrinkage and cell death.
research Coat condition, housing condition and measurement of faecal cortisol metabolites - a non-invasive study about alopecia in captive rhesus macaques (Macaca mulatta)
Alopecia in captive rhesus macaques is affected by season, sex, age, housing, and stress, with complex links between stress hormones and hair loss.
research Molecular Dissection of Mesenchymal–Epithelial Interactions in the Hair Follicle
Understanding gene expression in hair follicles can reveal insights into hair growth and disorders.
research Cultured human and rat tooth papilla cells induce hair follicle regeneration and fiber growth
Tooth papilla cells can help regenerate hair follicles and grow hair.
research Different gene expression profile observed in dermal papilla cells related to androgenic alopecia by DNA macroarray analysis
Hair loss in balding individuals is linked to changes in specific hair growth-related genes.
research Effect of constant-release melatonin implants and prolonged exposure to a long day photoperiod on prolactin secretion and hair growth in mouflon (Ovis gmelini musimon)
Melatonin implants and long daylight hours alter the timing of hormone release and hair growth in mouflon sheep.
research Estrogens and Human Scalp Hair Growth—Still More Questions than Answers
The effects of estrogen on human hair growth are unclear and need more research.
research Decreased Serum Ferritin and Alopecia in Women
Low serum ferritin levels are linked to hair loss in women.
research The expression of insulin-like growth factor 1 in follicular dermal papillae correlates with therapeutic efficacy of finasteride in androgenetic alopecia
Higher IGF-1 levels in hair follicles link to better finasteride results for hair loss.
research The Distribution of Estrogen Receptor β Is Distinct to That of Estrogen Receptor α and the Androgen Receptor in Human Skin and the Pilosebaceous Unit
Estrogen Receptor ß (ERß) is the main hormone controller in human skin and hair follicles, not Estrogen Receptor α (ERα) or the Androgen Receptor (AR).
research Prolactin and Its Receptor Are Expressed in Murine Hair Follicle Epithelium, Show Hair Cycle-Dependent Expression, and Induce Catagen
Prolactin affects hair growth cycles and can cause early hair follicle regression.
research Analysis of genetic polymorphisms of steroid 5α-reductase type 1 and 2 genes in Korean men with androgenetic alopecia
Gene differences may affect baldness treatment response in Korean men.
research Androgen‐inducible TGF‐β1 from balding dermal papilla cells inhibits epithelial cell growth: a clue to understanding paradoxical effects of androgen on human hair growth
Androgens may cause hair loss by increasing TGF-beta1 from scalp cells, which inhibits hair cell growth.
research Trans‐species hair growth induction by human hair follicle dermal papillae
Human hair follicle cells can grow hair when put into mouse skin if they stay in contact with mouse cells.
research The genetics of androgenetic alopecia
Genes and hormones cause hair loss, with four genes contributing equally.
research Androgen receptors are only present in mesenchyme-derived dermal papilla cells of red deer (Cervus elaphus) neck follicles when raised androgens induce a mane in the breeding season
Red deer only have androgen receptors in neck hair cells for mane growth during breeding season.
research The biology of androgenetic alopecia
research 17β-Estradiol and ICI-182780 regulate the hair follicle cycle in mice through an estrogen receptor-α pathway
Estradiol stops hair growth in mice, but an antagonist can reverse this effect.
research Effects of 17-β-Estradiol and ICI 182 780 on Hair Growth in Various Strains of Mice
17-β-Estradiol applied to the skin stops hair growth, while ICI 182 780 helps hair grow in mice.
research Expression of mRNA for androgen receptor, 5alpha-reductase and 17beta-hydroxysteroid dehydrogenase in human dermal papilla cells
research The mRNA for Protease Nexin-1 is Expressed in Human Dermal Papilla Cells and its Level is Affected by Androgen
Human skin cells contain Protease Nexin-1, and male hormones can decrease its levels, potentially affecting hair growth.
research Androgen-Dependent Beard Dermal Papilla Cells Secrete Autocrine Growth Factor(s) in Response to Testosterone Unlike Scalp Cells
Beard cells, unlike scalp cells, produce growth factors in response to testosterone, which may explain differences in hair growth.
research Finasteride in the treatment of men with androgenetic alopecia
Finasteride safely and effectively treats male pattern hair loss, but may cause reversible sexual issues and harm male fetuses.
research Effects of Self-Perceived Hair Loss in a Community Sample of Men
Men who think they are losing hair feel worse about themselves, especially if they are younger.
research Balding hair follicle dermal papilla cells contain higher levels of androgen receptors than those from non-balding scalp
Cells from balding scalps have more androgen receptors than cells from non-balding scalps.
research Inhibition of Hair Growth by Testosterone in the Presence of Dermal Papilla Cells from the Frontal Bald Scalp of the Postpubertal Stumptailed Macaque
Testosterone can slow hair growth in adult monkeys, but a blocker called RU 58841 can counteract this and potentially help hair regrow.
research An estrogen receptor pathway regulates the telogen-anagen hair follicle transition and influences epidermal cell proliferation.
Estrogen affects hair growth and skin cell multiplication.
research A comparison of the culture and growth of dermal papilla cells from hair follicles from non-balding and balding (androgenetic alopecia) scalp
research Androgen Induction of Follicular Epithelial Cell Growth Is Mediated via Insulin-like Growth Factor-I from Dermal Papilla Cells
Male hormones promote hair cell growth by using a growth factor from nearby skin cells.
research Bilateral adrenalectomy induces early onset of summer fur growth in mink (Mustela vison)
Removing mink's adrenal glands causes their summer fur to grow earlier.
research Androgens and human hair growth
research 9 Role of 5α-reductase in health and disease
5α-reductase is essential for male sexual development and its inhibitors have potential in treating various conditions related to hormone action.
research Cultured dermal papilla cells from androgen-dependent human hair follicles (e.g. beard) contain more androgen receptors than those from non-balding areas of scalp
Beard hair follicles have more androgen receptors than non-balding scalp hair follicles.
research Thyroid and gonadal regulation of hair growth during the seasonal molt in the male European badger, Meles meles L
Thyroid and gonadal hormones control seasonal hair growth and molting in male European badgers.
research The hair cycle on the human thigh and upper arm
Men's thigh hair grows longer and has a longer growth cycle than women's, but arm hair growth is similar between genders.
research Classification of the types of androgenetic alopecia (common baldness) occurring in the female sex
Common baldness, also known as Androgenetic Alopecia, is caused by a combination of genetic factors and hormones called androgens.
research HAIR DIAMETER IN FEMALE BALDNESS
Women with thinning hair have thinner hair strands than women without hair loss.
research HAIR LOSS IN WOMEN
Hair loss in women often doesn't follow a pattern, isn't linked to age, may be genetic, and can be related to thyroid issues or other health factors.