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A few days ago, someone on my flist posted something that had a casual mention of a drug that is used to cause lactation. I don't remember who it was, or what the post was actually about, see, but I ended up getting sucked down the Intertubes for hours because if ot, and it was some hours before I re-surfaced in the middle of a lake many miles away.

Lactation in human beings is largely mediated by a hormone called, naturally enough, "prolactin." But that's not the interesting bit. The interesting bit is about sex.

This is prolactin. It's a hormone produced by human beings in the breast during breast feeding (it causes the production of milk) and in the brain during orgasm. As is typical with many hormones, it serves double duty and has a number of different roles; evolutionary biology never starts with a clean slate, so we get hormones in one part of the body repurposed to do something completely different in another part of the body (and we also get fucked-up design night mares like the knee...but I digress).

Its role in the brain is interesting. it's what keeps you from wanting to fuck all the time.

When (most) people have an orgasm, there's a drop in sexual arousal immediately afterward. There's usually a refractory period, during which you can't get off again, and there's a generalized, overall decrease in libido. The length of time it lasts varies all over the map; for some folks it's a few minutes, for other folks it's the rest of the day, or at least until the rerun of "Buffy the Vampire Slayer" is over. Prolactin is the cause.

When it's released in the brain during and after orgasm, the role of prolactin is to stomp all over your arousal like it was a narc at a biker rally. A while ago, a bunch of scientists far better at getting funded than I am worked out a way to get paid for watching people masturbate; they found some heroic volunters, hooked them up to blood sampling equipment, then monitored the levels of various hormones in their blood while the volunteers masturbated to orgasm. The experiment was repeated with volunteers who could experience multiple orgasms.

What they found, aside from the fact that getting paid to watch women masturbate is really hot, is that the production of prolactin is directly correlated to the post-orgasmic crash; the prolactin remains in the body for hours (or longer); while the level of prolactin is high, arousal is difficult or impossible; and people who have multiple orgasms don't have this spike in prolactin in their blood after they get off.

All this, I already knew.

Being the transhumanist that I am, which is often just a way of saying being the pragmatist that I am, I've long thought that the easiest path to becoming multiply orgasmic would probably be to develop a drug that blocks the action of prolactin. Snap, job done. Take a pill, get off again and again and again and again. And then some more after that.

What I didn't realize was that such drugs already exist.

So here I am, reading LJ, and I find a passing reference to a drug that induces lactation. Since I hadn't heard of it before, I do what I always do with novel words or ideas--I consulted the Oracle at Google.

The Oracle at Google is wise and all-knowing, but she can also be a temperamental and difficult oracle, for she often sows her information with the seeds of more things you didn't know, which in turn lead to more things you didnt know, and still more things you didn't know, inducing you to submerge yourself in the waters of human knowledge and not come up for air until you're reading about the history of Hadrian's Wall when all you'd asked for was perhaps the best ways to trim a cat's claws.

Anyway, lactation can be induced in women by means of drugs that enhance the action of prolactin, or that stimulate prolactin production. Lactation can also be prevented, naturally enough, by drugs which block the effects of prolactin, of which there are two, cabergoline and bromocriptine.

Now, there are a lot of other reasons why you might want to block prolactin, which have nothing to do with lactation. Excess prolactin is responsible for a number of other conditions; certain forms of pituitary disease cause excess levels of prolactin, which can lead to cancers, arthritis and other autoimmune diseases, and a whole host of other stuff you don't want. So there's a medical need for drugs that block prolactin.

As it turns out, there's a relationship between prolactin and a completely different compound, the neurotransmitter dopamine. Dopamine also serves multiple functions. It's the neurotransmitter that signals nerves in your voluntary motor centers of your brain; when you think about moving your arm, your motor centers produce dopamine, which turns into the nerve impulses that make your arm actually move.

It's also a key component of the so-called "reward center" of the brain that mediates feelings of pleasure; when you delight in anything from a beautiful painting to the knowledge that you're getting paid to watch people masturbate, dopamine is the reason. And dopamine mediates much of the sexual system of the brain, including the functions that cause physical arousal.

Dopamine and prolactin are mutually antagonistic. Dopamine tends to inhibit the function and production of prolactin, and excess prolactin tends to inhibit the function of dopamine. For that reasons, things that are antagonistic to prolactin tend to enhance the function or quantity of dopamine in the brain, and vice-versa.

Okay, so here's where things get really cool.

There is a devastating disease called Parkinson's disease which results in gradual, irreversible destruction of the dopamine-producing cells in the motor area of the brain, which leads to gradual, creeping paralysis. Because it's caused by the loss of dopamine-producing cells, anything which acts to stimulate the production of dopamine in the brain will tend to reverse the paralysis, so dopamine-enhancing drugs are often used to treat Parkinson's.

Now, as I've already mentioned, drugs that block prolactin tend to enhance dopamine, and vice versa. The drug bromocriptine is a prolactin antagonist and a dopamine agonist; for that reason, it's often used to treat both Parkinson's disease and certain pituitary disorders that cause excess prolactin production. The down side is that it has a number of fairly nasty side effects in some people, including such unpleasantness as psychosis.

Cabergoline is another drug that works the same way as bromocriptine; like bromocriptine, cabergoline is used to treat Parkinson's disease and pituitary disease. It, too, blocks prolactin and enhances dopamine, and it has fewer nasty side effects.

One interesting side effect reported in both men and women being treated for things like Parkinson's is multiple orgasms.

Which is a hell of a side effect, if you ask me.

In fact, cabergoline (and, to a lesser extent, bromocriptine) are sometimes prescribed off-label to counteract the sexual side effects of antidepressants (which modify the action of dopamine), and as treatments for sexual dysfunction.

So it turns out, as is often the case, that not only was I right in thinking that a prolactin-blocking drug might allow folks to have multiple orgasms, but that, as usual, other folks had already beaten me to the punch.

The moral lesson here is to be careful what you write about in your LiveJournal. The simple mention of an unfamiliar word can suck someone down into the bowels of the Internet for hours on end, and not only that, can spread viral-like through LiveJournal psts to other folks, who may get sucked down for hours on end plumbing the depths of biochemistry or stellar nucleosynthesis, as this post in shiva_kun's journal so aptly shows. In the interests of getting things done in the office, I hereby ask that all the folks on my friends list refrain from posting anything interesting, and instead confine themselves to discussions of reruns of "Friends" for the next three days, kay?


( 37 comments — Leave a comment )
Nov. 24th, 2008 05:08 pm (UTC)
I would have been so much more interesting if the Friends had been poly and kinky. *wink wink*
Nov. 24th, 2008 05:24 pm (UTC)
And, by the way, not only am I still lactating, but I do have a refillable prescription for Reglan that was prescribed to boost my milk production early on, and I've got plenty left. The prolactin obviously explains my painfully reduced sex drive, but my monkey mind is now wondering about Michael J. Fox. When did he first know he had Parkinson's? And is he prepared to bring sexy back?
Nov. 24th, 2008 06:05 pm (UTC)
Nov. 24th, 2008 07:00 pm (UTC)
Prolactin agonist and dopamine antagonist. Yikes. Seems like it'd make you cranky, irritable, and uninterested in sex.
Nov. 25th, 2008 02:29 am (UTC)
Well I'm not that cranky and irritable (maybe a little bit when people at TGIFriday's are seriously stupid :P), but the sex part is just weird. I'm mentally still very interested in sex, but my physical sex drive is just about in park. Maybe you should have run some experiments on me when we were there. Hehe. But seriously, I've even tried looking at porn that I know usually make me hot, and I've got nothing. About once every 2 or 3 months I suddenly get very horny, but as soon as I have an orgasm it passes completely. No going back for more later. No next night follow up. And what's more, if I masturbate I have no interest in anyone else at all. It's really sad. I wonder how fast my sex drive will return when I wean Saku?
Nov. 24th, 2008 05:42 pm (UTC)
who says they weren't....didn't the girls kiss each other to win an apartment back in one episode? I also suspect that Phoebe was open, or at least BI but didn't readily share in view of the public.

Maybe its just wishful thinking because I always thought Phoebe was hot.
Nov. 24th, 2008 07:00 pm (UTC)
Icon love!
Nov. 24th, 2008 09:15 pm (UTC)
Nov. 24th, 2008 05:23 pm (UTC)
yeah sure, this is all well and good about the cabergoline... BUT WHERE DO I GET ME SOME!!??

Nov. 24th, 2008 05:25 pm (UTC)
This would certainly make chemistry classes more interesting if they presented stuff like this.
Nov. 24th, 2008 05:43 pm (UTC)
but then they would HAVE to teach comprehensive sex ed as well......
there's an idea.....
Incorporate comprehensive sex ed into a science class about hormones and medical side effects?

Nov. 24th, 2008 05:48 pm (UTC)
But Franklin... now your loyal readers need to know about people's personal experiments with cabergoline.

Off to teh Google mines, I guess...
Nov. 24th, 2008 08:12 pm (UTC)
Yanno, the list of potential side effects kind of killed my desire to experiment that way. Now, granted the risks seem associated with long-term use (as treatment for Parkinson's, for instance), but even so.

I've read that cabergoline is sometimes used recreationally for sex, which sounds like a lot of fun. There's a drug (sadly, injection-only) that used to be used to treat erectile dysfunction, before the age of Viagra; it's a lot less popular now, but it acts directly on the penis to produce an erection that persists for as long as the drug is biochemically active, independent of arousal. I've thought it might be an interesting experience to be tied down, given a dose of both that and a prolactin-blocker, and become a human sex toy for however long my partner wanted to keep using me--independent of my own level of arousal or sexual desire. I doubt it's practical to make it happen in reality, though.
Nov. 24th, 2008 09:16 pm (UTC)
I have a client who uses the injection and it works pretty well. Starts working in just a minute or two and doesn't seem to have the problems with delaying orgasm that Viagra does.
Nov. 24th, 2008 09:18 pm (UTC)
But hella fun to think about :)

no more hour long BJ's to get a second round.
Nov. 25th, 2008 01:10 am (UTC)
Since when do fantasies have to be "practical"?
Nov. 24th, 2008 05:51 pm (UTC)
Well it does make sense. When I was lactating I would often "let down" after orgasm, my breasts would leak. DH seemed to enjoy it but he didn't have to do the laundry to get a sour milk smell out. It makes sense also that I had far less libido when lactating as well. All the same hormones.
Nov. 28th, 2008 01:13 am (UTC)
This is fascinating stuff!

My GF is lactating and has been pretty dismayed by the concomitant drop in libido, although she's reassured to know that it does come back eventually (since I went through the same thing when nursing my daughter.)

The post-orgasm letdown does seem to be less pronounced after you've been nursing for some months, although that probably has a lot to do with the fact that you're nursing fewer times per day.

Franklin, this is a fascinating post!

-- A <3
Nov. 24th, 2008 05:52 pm (UTC)
That was both sexy AND educational!!!

My Brain hereby salutes you! ^_^
Nov. 24th, 2008 06:23 pm (UTC)
Very, very interesting.

Now, tell me, if you please, if you can, how the prolactin/dopamine antagonism works with bipolar hypersexuality. I know that as a bipolar, and someone who goes hypersexual during mania, an orgasm does not cause a drop in the arousal. If anything, orgasms only increase the desire for sex. Any thoughts on why?
Nov. 24th, 2008 08:01 pm (UTC)
That makes perfect sense, actually. My understanding of bipolar disorder (which may be flawed, as I haven't had a class in neurobiology in more than twelve years now, and this is a science that's moving very fast) is that the depressive part of the cycle is often accomplanied by a significant drop in available levels of dopamine, and that the manic phase is often accompanied by increased levels of both dopamine and dopamine precursors, with attendant hyperactivity of the brain's reward centers.

Now, if that's correct (and I will concede that it might not be), I would expect to see attendant variations of prolactin production during the cycle as well, with prolactin at a low point during a manic phase. Which would seem to be consistent with what you're describing.
Nov. 24th, 2008 08:58 pm (UTC)
That's really quite, quite intriguing.
Dec. 22nd, 2008 12:14 am (UTC)
Wellbutrin (which is a dopamine reuptake inhibitor) had this effect on me when I first started taking it. (I personally found it annoying.)
Nov. 24th, 2008 06:46 pm (UTC)
Some more prolactin factoids, with no commentary
Prolactin increases sense of smell.

Many anti-psychotics and some anti-depressants increase prolactin, which may be (at least partly if not fully) responsible for the sexual side effects of these drugs.

Chronically low levels of prolactin are associated with clinical depression.

Prolactin levels are correlated with the feelings of sexual satisfaction. Low prolactin = lowered feelings of satisfaction.

Prolactin levels following intercourse are 400 percent greater than levels after masturbation. (Not sure if this is gender-specific)

Male semen contains prolactin, which enters into the bloodstream of partners if no barriers are used during intercourse. This may be why rates of depression and suicide are lowered among women who have multiple male partners with no condom use.

My sources:


Nov. 24th, 2008 07:07 pm (UTC)
Re: Some more prolactin factoids, with no commentary
Another article you might be interested in about hormones released in men after ejaculation:

Nov. 24th, 2008 07:54 pm (UTC)
Re: Some more prolactin factoids, with no commentary
In all honesty, the feelings of sexual satisfaction aren't all that. In fact, I rather like not experiencing them.

Which isn't as whacky as it sounds. For me, it's the journey, not the destination, that matters. I find that if I reach the point of total sexual satiety, I'm actually kind of dissatisfied, because the experience of sex and the process of sex are both so much fun and are so interesting. (One thing I really like about sex is the way it lets me explore myself and my partner.)

I can usually get off multiple times during sex--low prolactin, I suppose--but I find that I tend to want to hold back a little bit from total satiety during sex, deliberately, just because keeping that edge of sexual arousal is so much fun.
Nov. 24th, 2008 10:08 pm (UTC)
Re: Some more prolactin factoids, with no commentary
I like a bit of both, different at different times--the feeling of satisfaction AND that of being insatiable. I would be curious about my own prolactin levels--I am definitely multi-orgasmic and generally have a very high sex drive. I only rarely feel "done" after sex--sex generally energizes me rather than making me sleepy. And I have found that since going on Ritalin for ADHD, my sex drive has increased even more--which makes sense since Ritalin ups dopamine.

I've also noticed that though I always enjoy partnered and solo sex, NOTHING makes me feel as happy-good-almost-high as unbarriered intercourse with a male partner when he cums inside of me--and now that I know how much good stuff is in semen I better understand this.

It's all very interesting stuff, both personally AND professionally!
Nov. 24th, 2008 07:24 pm (UTC)
Also interesting, prolactin has a huge effect on estrogen, balance it right and you (well not you, but someone) could be multi-orgasmic and menstrual period free!
Nov. 24th, 2008 11:46 pm (UTC)
Ohhhh, now that sounds nice!
Nov. 25th, 2008 12:02 am (UTC)
Wow. I didn't know any of that crap. Thanks!
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Nov. 25th, 2008 04:42 pm (UTC)
The most interesting thing about this, aside from the use of these drugs to treat sexual dysfunctions...

...is that Turtle is taking the opportunity to give us stories with morals.
Feb. 6th, 2009 11:17 am (UTC)
F... we have so much in common. I know I have said this before but really... wow. I was wondering if you were also on face book? I looked but couldn't find. Just curious.
Jun. 9th, 2011 08:47 pm (UTC)
If you look at the FDA fact sheet on cabergoline, you will see that the drug has potential cardiac side affects including high blood pressure and stroke. Not sure popping more than once in fifteen minutes is worth brain death or a heart attack. Of course if you are already brain dead and live according to the law of the little head, then full dopamine ahead and keep it up and coming.
Sep. 29th, 2011 08:39 pm (UTC)
prolactin withdrawal
The reason that I found this blog was that I was searching the internet for a reason why I had the first multiple orgasm of my life two weeks after I went cold turkey and stopped breastfeeding my son. Wow. I love science.
Mar. 2nd, 2012 09:19 am (UTC)
User calyupsos referenced to your post from 01 saying: [...] CHECK IT OUT PEOPLE, IT'S EXTREMELY WELL WRITTEN: Biochemistry and sex...and hey, multiple orgasms! [...]
( 37 comments — Leave a comment )