More than any other factor, testosterone has been associated with the health and longevity of men.
Its presence is believed to be a risk factor for many health problems, including prostate cancer.
However, a new review published in The Lancet medical journal has concluded that there is no scientific basis to recommend that testosterone levels be raised.
“The evidence that has been accumulated over the past several decades is that testosterone is not a ‘gateway’ to cancer,” said Dr. Raghunath Bhattacharya, director of the Institute for Molecular Biophysics and Biomedicine at King’s College London.
It’s more the case in women with a low level of testosterone.” “
Even in men who have a low testosterone level, it is not always associated with increased risk of cancer.
It’s more the case in women with a low level of testosterone.”
The review, led by Professor Stephen Stempel, a professor of physiology at the University of Western Australia, looked at the effect of testosterone on cancer cells and compared it to a placebo in mice.
A comparison of testosterone and a placebo is not definitive because mice do not have a similar metabolism, so the results could have been influenced by other factors.
But the study concluded that testosterone has no known role in the development of prostate cancer in humans.
What is testosterone?
According to the US National Institutes of Health, testosterone is the sex hormone that binds to the receptors on the surface of male testicles, which make the male reproductive organs (the prostate, ovaries, fallopian tubes and fallopian tube lining).
The testicle then secures itself to the urethra, the passage between the bladder and the anus, which carries urine and sperm to the egg and uterus.
In the lab, testosterone acts as a growth factor that can be expressed as growth hormone (GH) or as an adiponectin, which acts as an appetite suppressant.
A study published in 2012 found that a single injection of testosterone (1,000 micrograms) into male rats increases the growth of testicular cancer cells in their urine and increases their growth rate, while in a mouse model, testosterone also increased the number of cancerous cells.
The study found that testosterone, in mice, also increased cancer cell growth in their urethral system, where the cancer cells were located.
The increase in tumor growth was more pronounced in male rats than in female rats.
In a 2012 study published by the journal Nature, the researchers injected testosterone into the testes of male rats that were not already genetically predisposed to cancer.
The rats developed tumors in three different organs: the liver, brain and prostate.
The hormone, which was injected intravenously, caused the animals to develop tumors in the testicles of both males and females.
However the tumors in both males who were predisposing to cancer and females who were not showed no increase in their tumors.
“When we injected testosterone directly into the prostate, it increased tumor growth in both rats,” said the study’s senior author, Dr. Mark J. Kastel, a biochemist at the Icahn School of Medicine at Mount Sinai.
“This is a promising finding, but it is unclear whether it would translate to humans.”
“What’s important is that the rats were not genetically predisposed to cancer or not,” said Bhattocharya.
“We were interested in determining whether the growth effect of the testosterone would occur in humans.”
The study’s authors did not find that the growth effects of testosterone would be sufficient to influence cancer cell survival in the rats.
What are the mechanisms for how testosterone affects the growth and survival of cells?
In an animal model of prostate carcinoma, testosterone affects cancer cells by binding to and inhibiting the protein called Src, which is responsible for signaling the body to make proteins called adhesins.
“Src is important for the normal functioning of the cell,” said Kastels co-author, Dr, Daniel R. Sussman, a scientist at the National Cancer Institute (NCI) at the U.S. National Institutes.
“And when we lowered the level of Src in the cells, they died.” “
“This was a surprising finding,” said Sussmans co-investigator, Dr., Daniel Sussmann, a molecular biologist at the Institute of Biochemistry and Molecular Biology at Johns Hopkins University. “
And when we lowered the level of Src in the cells, they died.”
“This was a surprising finding,” said Sussmans co-investigator, Dr., Daniel Sussmann, a molecular biologist at the Institute of Biochemistry and Molecular Biology at Johns Hopkins University.
“Although the study was a bit small and the number is small, it was a very interesting finding.
It seems like the SRC-2 protein plays a critical role in regulating the survival and growth of cells.”
The authors did find that testosterone did not affect Src levels in the prostate