non voglio sminuire le tue osservazioni ma devo ammettere che si tratta di un'osservazione empirica, non suffragata da alcunchè di scientifico.
Quanto agli studi, mi sembrerebbe pletorico postarne, visto che com'è noto ci sono e dimostrano l'efficacia del prodotto in molti casi.
Per quanto attiene allo azione del minodixil, che ipotizzi sfrutti gli androgeni, ritengo questa intuzione abbastanza improbabile.
Se così fosse, dovrebbe farli cadere:
Differences in testosterone metabolism by beard and scalp hair follicle dermal papilla cells.Thornton MJ, Laing I, Hamada K, Messenger AG, Randall VA.
Department of Biomedical Sciences, University of Bradford, West Yorks, UK.
OBJECTIVE: Androgens have paradoxically different effects on hair follicles depending on body site, stimulating beard growth while inducing regression in some areas of the scalp. The mesenchyme derived dermal papilla at the base of the hair follicle regulates many aspects of the growth of follicular epithelium, and is probably the site of androgen action. Since 5 alpha-dihydrotestosterone is considered to be the active intracellular androgen in many target tissues and is required for some androgen-mediated hair growth, such androgen-sensitive cells should contain 5 alpha-reductase. This study was designed to investigate whether cultured human dermal papilla cells contain 5 alpha-reductase and whether the metabolic capacity varies with the body site of the follicle in line with the clinical picture. DESIGN: Testosterone metabolism in cultured dermal papilla cells from androgen sensitive beard follicles was compared with less androgen dependent non-balding scalp follicles. Primary cell cultures were established from follicles of 11 patients with normal hair growth. The cells were grown to confluence in 10-cm Petri dishes and incubated with 5 nM 3H-testosterone in serum-free medium for 2 hours. The cells and the culture medium were collected separately for individual analysis. MEASUREMENTS: Unlabelled carrier and 14C-marker steroids were added to both the cell and medium extracts before separation by thin-layer chromatography. The individual steroid identities were confirmed by recrystallizing up to five times to a constant 3H/14C ratio. RESULTS: Testosterone was taken up by both cell types; significant amounts of 5 alpha-dihydrotestosterone were recovered inside beard cells, but not in scalp cells, whereas androstenedione was identified in both. An unidentified compound was present intracellularly in both cell types, but was not present in the culture medium. 5 alpha-Dihydrotestosterone was present only in the culture medium of beard cells but androstenedione was present in a similar amount in the medium from both cell types. The presence of other steroids could not be confirmed in either the cell extracts or the culture medium. CONCLUSIONS: The production of 5 alpha-dihydrotestosterone by beard cells concurs with the poor beard growth in men with 5 alpha-reductase deficiency, supporting our hypothesis that androgens mediate their effects on the hair follicle via the mesenchyme-derived dermal papilla.
Quanto poi alle quantità utilizzabili, sono perplesso:
ho letto che un dermatologo del sito, parlando dell'interazione tra minoxidil e camp, sostiene che dosi troppo alte, aumentando l'adenilcilasi e la fosfodiesterasi, potrebbero essere nocive.
Tuttavia, non so quanto questa affermazione possa condividersi, dal momento che il camp non è un fattore di regalazione dei geni ma solo un attivatore metabolico, per cui si limita (ma si tratta di una funzione importantissima) per lo più a velocizzare o rallentare processi biochimici.
Evidence that activation of protein kinase A inhibits human hair follicle growth and hair fibre production in organ culture and DNA synthesis in human and mouse hair follicle organ culture.Harmon CS, Nevins TD.
Preclinical Dermatology Research, Hoffmann-La Roche, Nutley, NJ 07110, USA.
We have investigated the possibility that protein kinase A (PKA) may play a part in regulating the activity of human and mouse hair follicles in whole organ culture. Human hair follicles were isolated from facial skin by microdissection, and hair follicle and hair fibre length measurements were made daily during suspension culture. Incubation of human hair follicles with dibutyryl-cAMP (db-cAMP) resulted in a dose-dependent inhibition of total cumulative follicle growth (IC50 = 100 mumol/L, 85% inhibition at 1 mmol/L). db-cAMP (0.5 mmol/L) also caused a rapid, partial inhibition of follicular DNA synthesis (20.3% inhibition at 6 h, 48.0% inhibition at 24 h). Human hair follicle growth was inhibited by the phosphodiesterase inhibitors 3-isobutyl-1-methylxanthine and Ro 20-1724, and by the adenylate cyclase activator, forskolin. In addition, db-cAMP inhibited DNA synthesis in organ cultures of whisker follicles isolated from neonatal mice by microdissection. Taken together, these findings indicate that agents which increase cAMP levels are potent inhibitors of human and mouse hair follicle growth, and suggest that PKA may play a part in the regulation of hair follicle activity in vivo.
Questo studio che ho trovato (ma di capelli mi occupo solo da pochi giorni), mi porta a ritenere che la conclusione possa essere condivisa (come si nota, si avrebbe una parziale inibizione di dna follicolare), ma lascia ancora dei problemi insoluti.
inoltre, mi colpisce che la forskolina, un attivatore dell'adenilciclasi, abbia un effetto inibitorio sulla crescita. Pensa che l'effetto finale sulla reazione a cascata è analogo a quello della xantine (anche se, forse, le xantine, le quali comuqneu hanno come risultato netto l'aumento di amp ciclico, agendo sulla fosfodiesterasi).
Bah, vorrei delucidazioni!
]cmq devo dire ke quando lo prendevo assiduamente mi venivano dei dolori intercostali incredibili...cmq ho deciso di passare a terapie naturali con il tempo..
