[Pharmwaste] Artificial progestins in women's drugs affect fish
Laurie.Tenace at dep.state.fl.us
Thu Jul 30 08:39:50 EDT 2009
Artificial progestins in women's drugs affect fish reproduction.
Jul 30, 2009
Zeilinger, J, T Steger-Hartmann, E Maser, S Goller, R Vonk, and R Länge.
Effects of synthetic gestagens on fish reproduction. Environmental Toxicology
and Chemistry doi: 10.1897/08-485.1.
Synopsis by Karen Kidd
This study reports for the first time that progestins, which are used in
combination with other hormones in birth control pills and hormone
replacement therapies, decrease egg production in fish.
Fish produced fewer - or no eggs at all - after only one to two weeks of
exposure to either of two different types of synthetic progestin hormones
found in women's reproductive drugs. The more potent of the pair of
progestins also lowered sperm production and affected behavior in male fish.
This is the first study to show that a progestin used in human
pharmaceuticals can affect fish reproduction at environmentally-relevant
levels. Women's contraceptives and menopausal drugs contain the progestins.
Progestins are synthetic versions of the natural hormones progestogens (or
gestagens, of which progesterone is an example). Progestogens help regulate
the menstrual cycle and are involved in maintaining pregnancy.
Progestins can be combined with estrogen in birth control and hormone
replacement therapy drugs. Alone, they act as a "mini-pill" to stop the
release of eggs from the ovary and to reduce the risk of cervical cancer in
menopausal women. Several different forms of progestins are used in these
medications, and they vary in their potency.
Women taking the birth control pill or hormone replacement therapies excrete
progestins in their urine. Though few studies have looked for progestins in
municipal wastewaters, one type used in the study - levonorgestrel - was
found at low levels in sewage effluents (15 parts per trillion) and surface
waters (1 part per trillion). Just like the estrogen hormones that have
received a lot of recent attention, fish living downstream of these
discharges are likely exposed to progestins.
In this study, a common fish species, the fathead minnow, was exposed to two
different progestins: the most heavily prescribed progestin in the birth
control pill (levonorgestrel) as well as a newer form used in contraception,
drospirenone. Fish were exposed to 0.8, 3.3 and 29.6 parts per trillion
(nanograms per liter) of levonorgestrel or 0.66, 6.5 and 70 parts per billion
(micrograms per liter) of drospirenone for 21 days (4 tanks per treatment
with one pair of fish per tank). Total numbers of eggs, numbers of eggs per
clutch, spawning behavior, coloration of the fish (a secondary sexual
characteristic controlled by hormones), and egg and sperm development in the
ovaries and testes were monitored and compared to fish in control tanks.
Reproduction in the fish was affected after only one week of levonorgestrol
exposure. Female fish exposed to the artificial hormone produced fewer eggs
(3-fold fewer than controls) at all exposure levels, had more eggs that
failed to mature and became masculinized at the higher concentrations. Male
fish produced fewer sperm, became less aggressive and were less interested in
spawning. After two weeks, egg production stopped in all of the exposure
The lowest concentrations of this progestin are likely to be found in rivers
downstream of wastewater discharges.
The other progestin, drospirenone, was much less potent, affecting fish
reproduction after two weeks. Concentrations 8,000 times higher (6.5
micrograms per liter) than the levonorgestrel treatments stopped egg
production and any breeding in the fathead minnow. However these levels would
not likely be found in the environment based on known use and dilution in
These results of the study are not surprising because fish - like people -
produce progestogens that are important for reproduction. In fish, the
hormones play a crucial role in helping eggs to mature.
Given their widespread use in pharmaceuticals and likely presence in the
environment, progestins should be considered as another class of hormones
with the potential to impact the health of wild fish.
Waste Reduction Section
Florida Department of Environmental Protection
2600 Blair Stone Rd., MS 4555
Tallahassee FL 32399-2400
Laurie.Tenace at dep.state.fl.us
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