May 12th, 2013 § § permalink
Are cell phones bad for sperm? They emit electromagnetic radiation, and some have questioned whether that may be harmful for sperm.
Researchers exposed sperm in a test tube to the typical 850 and 900 MHz frequencies of cell phone transmitters and found that its movement worsened, its inner cell life decayed, and bad reactive oxygen molecules that are thought to damage sperm increased.
But a man doesn’t commonly hold his sperm up against his cell phone’s transmitter, and there’s a lot of distance and stuff between his cell phone and his sperm. So what’s the information about cell phones and sperm in real life?
In a study of sailors in the Norwegian navy, men who were exposed to high power military equipment transmitting radiofrequency electromagnetic radiation had problems with infertility. The higher the exposure, the worse the infertility, which argues that the electromagnetic radiation was the factor damaging a man’s reproductive chances. (An interesting observation in the study was that higher exposure resulted in less boys and more girls at birth.) But the high power electromagnetic radiation in that study is still not quite real life use of a cell phone for a typical man.
In another study of men going to a fertility clinic, researchers divided them into four groups based on how much time they spent talking on a cell phone each day: none; less than two hours per day; two to four hours per day; and greater than four hours per day. As talk time went up, sperm count, motility, inner sperm cell life, and the number of normally shaped sperm went down.
Should men stay away from using cell phones to protect their sperm? The pieces of the puzzle aren’t enough to make a blanket recommendation like that yet. But in the meantime, it’s probably a good idea not to go wild on the cell phone if a man is trying to impregnate his partner.
March 13th, 2013 § § permalink
As I’ve written before in this blog, clomiphene is an effective if off-label treatment for men with low testosterone who want to preserve their fertility. If used directly, testosterone itself actually decreases the making of testosterone and sperm in a man’s testis. Clomiphene increases testosterone production in the testis by increasing the pituitary hormones that tell the testis to make testosterone.
In the March issue of Fertility and Sterility, a journal that I co-edit with Dr. Antonio Pellicer, Drs. Kim and co-authors review the published medical literature on treating low testosterone with clomiphene and other drugs besides testosterone. They conclude that clomiphene is a safe and effective treatment for men with low testosterone and note that less than one year of treatment with testosterone is usually reversible if a man wants his fertility to return. Unfortunately, we don’t know all that much about longer treatments with testosterone, and many men who have been on testosterone for several years do not have sperm return even with other forms of treatment.
Drs Kim and co-authors give us a nice review that supports the use of clomiphene for men with low testosterone who want to preserve their fertility.
November 27th, 2011 § § permalink
Bob recently asked about using hCG (human chorionic gonadotropin) rather than clomiphene to increase testosterone. As I explained in How Clomid Works in Men, clomiphene stimulates the pituitary to make luteinizing hormone (LH), which then acts on the Leydig cells in the testis to make testosterone. So why not use LH directly?
One way to take over the pituitary’s production of its reproductive hormones is to use human chorionic gonadotropin (hCG), which looks like LH to the body. It effectively stimulates the Leydig cells to make testosterone. But it’s expensive and must be injected. So if the pituitary is working, clomiphene may be a better choice to start. If the pituitary isn’t working, hCG can be tried. But if the man’s LH is already very high, neither clomiphene or LH will help all that much, as the man’s body is already trying that strategy by itself.
The pituitary also makes follicle stimulating hormone (FSH), which acts on the Sertoli cells around the developing sperm cells. To help stimulate the making of sperm in the testis, recombinant FSH (rFSH) or human menopausal gonadotropin (hMG) may be used. Like hCG, these drugs are expensive and must be injected.
Thanks for the question, Bob!
June 7th, 2011 § § permalink
May blew by, and I didn’t manage a single new post. The annual meeting of the American Urological Association and a big burst of research activity in my bioengineering lab did keep me busy, but really, there’s no good excuse, and it’s time to blog again.
One very active area of this blog is How Clomid Works in Men, with over a hundred comments to date. I’m grateful to Robert for inspiring this post. His question is, are there medications that decrease estrogen?
To review how the pituitary controls the making of testosterone in the testis, testosterone is converted to the female hormone estrogen, and rising levels of estrogen tell the pituitary to make less luteinizing hormone (“LH”). The role of LH in a man is to stimulate the testis to make testosterone, and as the pituitary sees more testosterone in the blood through the lens of estrogen, it tells the testis to make less testosterone by reducing LH. I likened this negative feedback system to a thermostat and a heater: as the room becomes hotter, the thermostat turns down the heater. Clomiphene binds tightly to the pituitary, (and hypothalamus for you biological sticklers), and tricks the pituitary into thinking less estrogen is bouncing around in the bloodstream. The pituitary labors to make more LH as a result, and the testis makes more testosterone. The drug tamoxifen works in a similar way.
But Robert’s question hinted at another way to trick the pituitary: there is a way to decrease estrogen directly so that the pituitary sees less of it and makes more LH.
The enzyme aromatase turns testosterone into estrogen. Drugs like anastrozole and testolactone block aromatase, causing estrogen to decrease in the blood. The pituitary makes more LH as a result, and the testis produces more testosterone. If a man has low testosterone and high estrogen, these drugs can simultaneously increase testosterone and decrease estrogen. In a study published in the Journal of Urology in 2002, doctors Raman and Schlegel report evidence that anastrozole seems to work a little better than testolactone, at least in terms of increasing sperm production. In that study, the doctors also suggest that these drugs are best used if the ratio of testosterone is less than ten to one.
As I wrote in my post on How Clomid Works in Men, all of these drugs are off-label for use in the male, meaning that the Food and Drug Administration didn’t approve their use in men. That doesn’t mean that they can’t be used. It means that doctors need to tell patients what we know about these drugs, allowing for an informed decision on their use. It also means that many of the questions we have about these drugs don’t have answers. A good question about aromatase inhibitors in men is whether estrogen plays an important role in some health concerns in men, and if it is decreased for a long period of time, can other health problems occur? We don’t know. My current practice for prescribing aromatase inhibitors is mostly to limit their use to male fertility, and to stop the medication as soon as possible.
So there you have the two basic ways that pills can trick the pituitary into telling the testis to make more testosterone. Thanks, Robert!
March 21st, 2011 § § permalink
The horrific earthquake and tsunami in northern Japan remind us that no matter how powerful we become or careful we are, nature asserts itself in ways that we can’t imagine. The nuclear engineers and technicians working to contain the radiation leaking from the damaged power plant in Fukushima are nothing short of heroic. Radiation can cause all sorts of ills, from acute sickness to cancer and infertility.
In the testis, developing sperm cells are exquisitely sensitive to radiation. Kyodo News reported that after an explosion at the Fukushima No. 2 reactor on March 15, radiation levels measured as high as 8,217 micro sievert or 0.8217 rem per hour. (Micro sievert and rem are units of radiation dosage.)
Does that amount of radiation harm developing sperm cells? I asked Marvin Meistrich, Ph.D., Professor of Experimental Radiation Oncology and the Florence M. Thomas Professor of Cancer Research at the University of Texas M. D. Anderson Cancer Center, a world’s expert in radiation and sperm. Dr. Meistrich explained that sustained exposure to 20 rem of radiation over 4 weeks caused sperm counts to drop to 1/10th of their original amount. At doses of 40-80 rem, sperm counts fell to about 1/100th of the starting number, and in some cases were wiped out entirely. At 200 rem, that drop to zero sperm became permanent. For one-time doses, Dr. Meistrich explained that 15-20 rem caused a short-term fall in sperm count, and 400 rem or more resulted in permanent loss of sperm.
We know that radiation changes DNA, the sperm’s precious genetic cargo. What we don’t know is what dose causes a harmful DNA change that damages a developing embryo or causes disease later in life.
The radiation leakage in Fukushima seems to be in the range at which damage to sperm occurs. I can only hope that the workers at Fukushima and the people near the plants are aware of the dangers and take action to protect themselves.