Pubdate: Tue, 25 Nov 2003
Source: National Public Radio (US)
Copyright: 2003 National Public Radio
Contact:  http://www.npr.org/
Details: http://www.mapinc.org/media/1296
Bookmark: http://www.mapinc.org/pot.htm (Cannabis)
Note: Transcript is of Morning Edition program

MARIJUANA'S EFFECT ON EARLY-STAGE EMBRYOS

BOB EDWARDS, host:

Scientists have shown that marijuanalike compounds have an effect on 
embryos. When scientists exposed mouse embryos to different levels of such 
compounds, it affected the way the embryos developed.  Those results appear 
in the current issue of the Proceedings of the National Academy of 
Sciences.  It could lead to new ways to improve human fertility.  NPR's Joe 
Palca reports.

JOE PALCA reporting:

The story of how researchers found the relationship between marijuana and 
the early embryo has a curious start. During the war in Vietnam, scientists 
noticed that some male fighters who smoked a lot of marijuana started 
growing breasts. The scientists thought they knew the reason why.

Mr. SUDHANSU DEY (Reproductive Biologist, Vanderbilt University Medical 
Center, Nashville): They thought that marijuana products probably behaved 
like estrogen.

PALCA: Sadhansu Dey is a reproductive biologist at Vanderbilt University 
Medical Center in Nashville.  Dey says it's well known that estrogen can 
cause men's breasts to grow but it wasn't clear why a product from a 
cannabis plant would do that, too.  At the time, Dey was focusing on how 
estrogen affected embryos.

Mr. DEY: So I was very intrigued about that, that way that cannabinite 
products could behave like estrogen.

PALCA: Some of these cannabinoid products are actually produced in the body 
and it was these Dey was most interested in.  He spent years studying mice 
trying to see if there was any relationship between these natural 
cannabinoids and estrogen and couldn't find any.  For a while, he was 
stumped.  He thought for sure that estrogen was crucial for controlling 
early embryo development. But then he decided to see whether the 
cannabinoids the mice were producing themselves were having their own 
direct effect on the embryo.  Dey says they were.

Mr. DEY: What we found, that at low dose, these embryos become 
activated.  At higher doses, it inhibits embryonic growth in vitro.

PALCA: In other words, these cannabinoids are sending chemical signals to 
the developing embryo, telling it when to grow.

Herbert Schuel is a reproductive biologist at the University of Buffalo.

Mr. HERBERT SCHUEL (Reproductive Biologist, University of Buffalo): The 
consequence of that is to regulate how the embryo is developing so that it 
can implant properly into the lining of the uterus and go on to develop 
into a little baby mouse.

PALCA: The idea that the body is producing its own marijuanalike compounds 
that are controlling the steps of development will take some getting used 
to. Fuller Bazer is a reproductive biologist at Texas A&M University.

Mr. FULLER BAZER (Reproductive Biologist, Texas A&M University): I think 
the surprising thing is that we usually associate cannabinoids, you know, 
with marijuana and that sort of thing, you know, as being high from a plant 
source rather than being produced in significant amounts by mammalian tissues.

PALCA: But cannabinoids from plant sources aren't completely out of the 
picture.  Sudhansu Dey says it's likely that cannabinoids taken into the 
body by smoking marijuana will also send signals to the developing embryo.

Mr. DEY: If a woman is consuming regularly cannabinoid products, that can 
also have an added burden to the system and may, you know, interfere with 
pregnancy.  We don't know for sure but my studies suggest that.

PALCA: On a brighter note, Dey says understanding more about how natural 
cannabinoids work may help women who are having difficulties getting 
pregnant. Joe Palca, NPR News, Washington.
- ---
MAP posted-by: Jay Bergstrom