摘要:

SynopsisThe studies carried out on the metabolism of testosterone and other circulating androgens in human scalp skin and hair follicles have been reviewed with the aim of understanding the role of these androgens in male pattern alopecia (baldness).Le metabolisme des androgènes dans la calvitie chez l'homm

ISSN:0142-5463    

DOI:10.1111/j.1467-2494.1981.tb00262.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SynopsisLa peau possède toutes les protéines impliquées dans le mécanisme d'action des androgènes, et le métabolisme de ces androgènes y joue un rôle capital: non seulement la peau est le siège de la 5α‐réductase qui transforme la testostérone en son métabolite actif la DHT, mais elle peut aussi produire de la testostérone à partir d'androgenes moins actifs: Δ4‐androstènedione et dehydroépiandrostérone.L'activité de la 5α‐réductase est variable selon les régions: elle est élevée d'emblée et dans les deux sexes au niveau des organes génitaux externes, quelle que soit la sécrétion d'androgenes. Elle s'élève à la puberté, surtout dans le sexe masculin, et apparaît androgéno‐dépendante, au niveau des zones à caractére sexuel secondaire et notamment du follicule pilo‐sébacé.Les modèles pathologiques viennent confirmer l'importance de cette étape métabolique: le déficit en 5α‐réductase est cause de pseudohermaphrodisme masculin, son excés d'activité est responsable d'hirsutisme idiopathique.La connaissance des diverses étapes du mécanisme d'action des androgènes est indispensable à toute tentative thérapeutique qu'elle soit androgénique ou anti‐androgénique, systémique ou topique.SummaryIn human beings, androgen metabolism plays an important role in mediating the action of male hormones upon target structures of the skin. First, human skin is capable of transforming inactive steroids supplied through the blood, such as androstenedione and dehydroisoandrosterone, into the active androgen testosterone. Second, human skin is able to reduce testosterone to 5α‐DHT, an essential prerequisite, during embryogenesis, for the male differentiation of target structures derived from urogenital sinus. At puberty, hair growth in sexual areas of skin also requires the transformation of testosterone to DHT.Regulation of 5α‐reductase activity varies according to the anatomical site of the enzyme. In foetuses, 5α‐reductase activity present in tissues derived from the urogenital tract does not seem to be androgen‐dependent, since it is acquired before the onset of testosterone secretion by foetal testis. By contrast, the enzyme that mediates development of certain secondary sex characteristics, such as pilosebaceous gland activity in sexual areas, is clearly androgen‐dependent, since it is absent before puberty and in persons with hypogonadism.These differences in the control of the 5α‐reductase activity mediating the appearance of either primary or secondary sex characteristics are important and may explain the differences in 5a‐reductase activity observed in adult skin of both sexes derived from different sexual areas.In addition, the knowledge of androgen relation to the skin is necessary in order to understand the action of the

ISSN:0142-5463    

DOI:10.1111/j.1467-2494.1981.tb00263.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SynopsisAn experimental model using the ‘Rhino’ hairless mouse has been developed for screening comedolytic agents.The skin of this animal presents a high density of spontaneous comedos which appear in histological slices as cystic formations with a large diameter (D) and an open narrow neck (d). The ratio d/D expresses the ‘comedo profile'. Statistical evaluation of this value by standardized measurement allows the quantification of comedolytic activity of pharmacological agents.Un nouveau modèle pour la mesure de l'activité comé

ISSN:0142-5463    

DOI:10.1111/j.1467-2494.1981.tb00264.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SynopsisAlthough eccrine sweat glands are present in the foot pads of many mammals, and are abundant in the general body skin of many of the higher primates, it is only in man that these glands have a thermoregulatory function and are cosmetically significant. The expansion in sales of various antiperspirant products containing complexes of aluminium and zirconium has resulted in many studies, whose aim is to elucidate the mode of action of these substances.Sweat production in the rat foot padin vivohas been studied, and its modification following topical application of various polyvalent cations. Results of studies of protein precipitation by these cations are also discussed.Etude de l'action de certains cations polyvalents sur l'anhidrose cutanée

ISSN:0142-5463    

DOI:10.1111/j.1467-2494.1981.tb00265.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SynopsisA high pressure liquid chromatographic method is described for the determination of thioglycolic acid in hair waving fluids and depilatories. Prior to chromatography the acid is converted into a yellow‐coloured nitrobenzooxadioazole (NBD) derivative to permit HPLC detection at 464 nm. Optimum derivatization conditions could be obtained when 0.01% aqueous solutions of thioglycolic acid were heated with NBD‐C1 at pH 7. Hair waving fluids and depilatories are simply diluted with an aqueous buffer of pH 7 and, if necessary, clarified and filtered, before the derivatization procedure. To the mixture an internal standard Sunset Yellow FCF, Colour Index nr. 15985, is added before performing ion‐pair reverse phase HPLC. A reverse phase C18 column is used. The mobile phase is aqueous methanol, to which the counter ion, tetrabutyl‐ammonium phosphate, is added. Recoveries ranged from 97.8 to 100.7%.The proposed method permits a resolution of other possible mercaptocompounds such as thiolactic acid and thioglycerol. Sixty market samples of cold wave fluids and depilatories have been analysed by the proposed method, and the results compared with data obtained by iodometric titration.Le dosage de l'acide thioglycolique dans les liquides pour permanentes a froid et dans les cremes depilatoires par la chromatographie liquide haute pressio

ISSN:0142-5463    

DOI:10.1111/j.1467-2494.1981.tb00266.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SynopsisPABA (p‐aminobenzoic acid), a highly regarded sunscreening agent, has recently been shown to exhibit different absorption characteristics when applied to excised hairless mouse epidermis than when in dilute alcoholic solution. In the present study the cause of the differences was investigated.The results show that at normal application amounts, considerable quantities of randomly dispersed PABA micro‐crystals exist on the skin surface. The forward scattering spectrum of PABA on skin resembled more closely that of micro‐crystalline aggregates than that of PABA in sol

ISSN:0142-5463    

DOI:10.1111/j.1467-2494.1981.tb00267.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY