The paradoxical effects of androgens on human hair growth

Vellus Hair

6.3.1 Human hair growth before and after puberty In utero the humanbodyiscoveredwith quite long, colourless lanugo hairs. These are shed before birth and at birth, or shortly after, babies normally exhibit pigmented, quite thick protective hairs on the eyebrows and eyelashes and variable amounts on the scalp by the age of three or four the scalp hair is usually quite well developed, though it will not yet have reached its maximum length. These readily visible pigmented hairs are known as...

The mechanism of androgen action in the hair follicle

Papilla Whisker

6.4.1 Hair growth in androgen insufficiency syndromes As described in Chapters 1 and 2 of this book, androgens from the blood stream enter the cell and bind to specific, intracellular androgen receptors, usually in the form of testosterone or its more potent metabolite, 5a-dihydrotestosterone. The hormone-receptor complex, generally in combination with transcriptional regulators then activates the appropriate gene transcription for that cell type. Androgen insufficiency patients without...

Generalized androgen insensitivity in humans

Partial Androgen Insensitivity Syndrome

Defective androgen action caused by cellular resistance to androgens causes the androgen insensitivity syndrome (AIS) (Hiort etal. 1996 Quigley etal. 1995). The end-organ resistance to androgens results in a wide clinical spectrum of defective virilization of the external genitalia in 46,XY individuals. Mullerian duct derivatives are usually completely absent because of the normal ability of the foetal testes to produce AMH. Since the AR gene has been cloned, it became obvious that inactivating...

Testosterone enanthate

Testosterone Enanthate Pharmacokinetics

Single-dose pharmacokinetics oftestosterone enanthate after intramuscular administration of 250 mg testosterone enanthate to seven hypogonadal patients and the best-fitted pharmacokinetic profile are shown in Fig. 14.6 (Nieschlag etal. 1976). Maximal testosterone levels in the supraphysiological range were seen shortly after injection (39.4 nmol l, tmax 10 h). Testosterone levels below the normal range were observed following day 12 after injection. The calculated values were 9911 nmol * h l...

Testosterone propionate

Injections Propionate

Single-dose pharmacokinetics of 50 mg testosterone propionate after intramuscular injection to seven hypogonadal patients and the best-fitted pharmacokinetic profile are shown in Fig. 14.4 (Nieschlag et al. 1976). Maximal testosterone levels in the supraphysiological range were seen shortly after injection (40.2 nmol l, tmax 14 h). Testosterone levels below the normal range were observed following day 2 (57 h) after injection. The calculated values for AUC were 1843 nmol * h l, forMRT 1.5 d and...