Masturbation induces a spike in prolactin levels that can last at least a couple of hours. There is also evidence to suggest that prolactin is a hair growth inhibitor. If there's any connection between masturbation and hair loss, prolactin could be the culprit. Read the two abstracts below.
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TAGOHL
Orgasm-induced prolactin secretion: feedback control of sexual drive?
Kruger TH, Haake P, Hartmann U, Schedlowski M, Exton MS.
Department of Medical Psychology, University of Essen, 45122 Essen, Germany.
Recent studies from our laboratory have investigated the hormonal response to various forms of sexual stimulation, including film, masturbation, and coitus in both men and women. This series of studies clearly demonstrated that plasma prolactin (PRL) concentrations are substantially increased for over 1h following orgasm (masturbation and coitus conditions) in both men and women, but unchanged following sexual arousal without orgasm. Here we discuss evidence suggesting that the PRL response to orgasm may play an important role in the control of acute sexual arousal following orgasm. Supporting this position, chronic elevations of PRL (hyperprolactinemia) produce pronounced reductions in animal sexual activity, and significant reduction of libido and gonadal function in both men and women. These data suggest that PRL may represent a peripheral regulatory factor for reproductive function, and/or a feedback mechanism that signals CNS centres controlling sexual arousal and behaviour. Thus, we propose a theoretical model of the role of PRL as a neuroendocrine reproductive reflex.
PMID: 11835982 [PubMed - indexed for MEDLINE]
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.
kfoitzik@yahoo.com
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.
PMID: 16507890 [PubMed - indexed for MEDLINE]