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Aw: UMFRAGE: Wie oft habt Ihr Sex bzw. Masturbation? [Beitrag #286651 ist eine Antwort auf Beitrag #286639] :: Mi., 11 Dezember 2013 22:17  
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protos
Beiträge: 168 Registriert: Juli 2013
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Knorkell schrieb am Wed, 11 December 2013 20:40protos schrieb am Wed, 11 December 2013 17:31Gibt Studien und viele Erfahrungsberichte dazu, also nix Müll. Aber mir schon klar, dass viele es nicht wahrhaben wollen, damit sie schön fleißig weiter wi***en können. 
Schaut euch mal Don Jon an 
Gib mal eine der Studien auf die bin ich ja mal gespannt.
Und Erfahrungsberichte sind in der Regel einen feuchten Furz wert.
Don Jon ist ziemlich gut, was hat das mit Haarausfall zu tun? Weil Joseph Gordon Levitt GHE`s hat? Gib mal ne Studie in denen man nachweisen kann, dass es keine Pornosüchtigen mit NW 0 gibt.
Don Jon hat nur Pornosucht zu tun. Natürlich gibt es Pornosüchtige mit NW0. Die haben dann einfach keine Veranlagung für AGA.
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.Foitzik K, Krause K, Conrad F, Nakamura M, Funk W, Paus R.
Department of Dermatology, University Hospital Hamburg-Eppendorf, University of Hamburg, Hamburg, Germany.
The prototypic pituitary hormone prolactin (PRL) exerts a wide variety of bioregulatory effects in mammals and is also found in extrapituitary sites, including murine skin. Here, we show by reverse transcriptase-polymerase chain reaction and immunohistology that, contrary to a previous report, human skin and normal human scalp hair follicles (HFs), in particular, express both PRL and PRL receptors (PRL-R) at the mRNA and protein level. PRL and PRL-R immunoreactivity can be detected in the epithelium of human anagen VI HFs, while the HF mesenchyme is negative. During the HF transformation from growth (anagen) to apoptosis-driven regression (catagen), PRL and PRL-R immunoreactivity appear up-regulated. Treatment of organ-cultured human scalp HFs with high-dose PRL (400 ng/ml) results in a significant inhibition of hair shaft elongation and premature catagen development, along with reduced proliferation and increased apoptosis of hair bulb keratinocytes (Ki-67/terminal dUTP nick-end labeling immunohistomorphometry). This shows that PRL receptors, expressed in HFs, are functional and that human skin and human scalp HFs are both direct targets and sources of PRL. Our data suggest that PRL acts as an autocrine hair growth modulator with catagen-promoting functions and that the hair growth-inhibitory effects of PRL demonstrated here may underlie the as yet ill-understood hair loss in patients with hyper-prolactinemia.
1: J Endocrinol. 2002 Mar;172(3):605-14. Links
Regulation of prolactin receptor expression in ovine skin in relation to circulating prolactin and wool follicle growth status.Nixon AJ, Ford CA, Wildermoth JE, Craven AJ, Ashby MG, Pearson AJ.
AgResearch, Ruakura Research Centre, East Street, Hamilton, New Zealand. allan.nixon@agresearch.co.nz
Seasonal patterns of hair growth are governed, at least in part, by levels of prolactin in circulation, and although receptors for prolactin (PRLR) have been demonstrated in hair follicles, little is known of their regulation in relation to follicular cycles. In this study, a photoperiod-generated increase in prolactin was used to induce a wool follicle cycle during which changes in PRLR expression in sheep skin were determined by ribonuclease protection assay and in situ hybridisation. mRNA for prolactin and both isoforms of PRLR were also detected in skin by reverse transcription and polymerase chain reaction. As circulating prolactin began to rise from low levels, PRLR mRNA in the skin initially fell. These changes immediately preceded the catagen (regressive) phase of the hair cycle. Further increase in prolactin resulted in up-regulation of PRLR during telogen (dormancy), particularly in the epithelial hair germ, to reach a peak during proanagen (reactivation). In anagen (when follicle growth was fully re-established), PRLR mRNA returned to levels similar to those observed before the induced cycle. Hence, this longer term rise and fall of PRLR expression followed that of plasma prolactin concentration with a lag of 12-14 days. PRLR mRNA was most abundant in the dermal papilla, outer root sheath, hair germ, skin glands and epidermis. Location of PRLR in the dermal papilla and outer root sheath indicates action of prolactin on the growth-controlling centres within wool follicles. These cycle-related patterns of PRLR expression suggest dynamic regulation of PRLR by prolactin, thereby modulating hormonal responsiveness of seasonally growing hair follicles.
Prolactin and its receptor are expressed in murine hair follicle epithelium, show hair cycle-dependent expression, and induce catagen.Foitzik K, Krause K, Nixon AJ, Ford CA, Ohnemus U, Pearson AJ, Paus R.
Department of Dermatology, University Hospital Hamburg-Eppendorf, University of Hamburg, Hamburg, Germany.
Here, we provide the first study of prolactin (PRL) and prolactin receptor (PRLR) expression during the nonseasonal murine hair cycle, which is, in contrast to sheep, comparable with the human scalp and report that both PRL and PRLR are stringently restricted to the hair follicle epithelium and are strongly hair cycle-dependent. In addition we show that PRL exerts functional effects on anagen hair follicles in murine skin organ culture by down-regulation of proliferation in follicular keratinocytes. In telogen follicles, PRL-like immunoreactivity was detected in outer root sheath (ORS) keratinocytes. During early anagen (III to IV), the developing inner root sheath (IRS) and the surrounding ORS were positive for PRL. In later anagen stages, PRL could be detected in the proximal IRS and the inner layer of the ORS. The regressing (catagen) follicle showed a strong expression of PRL in the proximal ORS. In early anagen, PRLR immunoreactivity occurred in the distal part of the ORS around the developing IRS, and subsequently to a restricted area of the more distal ORS during later anagen stages and during early catagen. The dermal papilla (DP) stayed negative for both PRL and PRLR throughout the cycle. Telogen follicles showed only a very weak PRLR staining of ORS keratinocytes. The long-form PRLR transcript was shown by real-time polymerase chain reaction to be transiently down-regulated during early anagen, whereas PRL transcripts were up-regulated during mid anagen. Addition of PRL (400 ng/ml) to anagen hair follicles in murine skin organ culture for 72 hours induced premature catagen development in vitro along with a decline in the number of proliferating hair bulb keratinocytes. These data support the intriguing concept that PRL is generated locally in the hair follicle epithelium and acts directly in an autocrine or paracrine manner to modulate the hair cycle.
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