Possibly negated by the increase in prolactin:
Orgasm-induced prolactin secretion: feedback control of sexual drive?
Krüger TH1, Haake P, Hartmann U, Schedlowski M, Exton MS.
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Abstract
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.
http://www.ncbi.nlm.nih.gov/pubmed/11835982
An interesting look at prolactinergic and doperminergic mechanisms post orgasm:
Prolactinergic and dopaminergic mechanisms underlying sexual arousal and orgasm in humans.
Krüger TH1, Hartmann U, Schedlowski M.
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Abstract
Dopaminergic mechanisms play a major role in modulating sexual behavior in humans and animals. Animal data demonstrate important interactions between the dopaminergic and prolactinergic system. As recently demonstrated, dopamine agonists have facilitatory properties for penile erection but may also enhance sexual drive and orgasmic quality. In contrast,
chronic elevations of prolactin inhibit appetitive as well as consummatory parameters of sexual behavior. Recent human studies show a marked increase in prolactin after orgasm in males and females. Concerning the biological relevance of acute prolactin alterations after orgasm, prolactin might serve as a neuroendocrine reproductive reflex for peripheral reproductive organs. Alternatively, prolactin may feedback to dopaminergic neurons in the central nervous system and thereby modulate sexual drive and satiation. Here, we provide a brief overview of the physiology of dopamine and prolactin in regulating sexual behavior. In addition, recent experimental and clinical evidence for a postulated feedback mechanism for prolactin and its implications for orgasmic disorders are discussed.
http://www.ncbi.nlm.nih.gov/pubmed/15889301