Premarin - Article Cenestin; Premarin
Premarin is a mixture of estrogens isolated from mare's urine (PREgnant MARes' urINe) made by Wyeth Pharmaceuticals. Premarin has been one of the most widely used drugs in the United States of America. Premarin became the form of estrogen most commonly used for hormone replacement therapy. The major forms of estrogen in Premarin are estrone (>50%), equilin (15-25%) and equilenin. The estrogens in Premarin are often called "conjugated equine estrogens" (CEE) because the estrogen molecules are generally present with hydrophilic side-groups attached such as sulfate. Thus, estrone sulfate is actually the major molecule in Premarin. Estrone sulfate is easily absorbed into the blood after Premarin pills are taken by women. Estrone sulfate is converted to estradiol, an active estrogen normally found in women. It is not clear if estrogens such as equilin that are foreign to the human body have effects in women that are significantly different from the estrogens like estradiol that are normally made in the human body.
Premarin is the subject of much contention. Animal rights activists claim that animal husbandry and urine collection methods used in Premarin's production cause undue stress and suffering to the mares involved. Additionally, there is an overabundance of poorly bred foals is produced by Pregnant Mare Urine (PMU) farms each year. Since larger horses produce more urine, most Premarin mares are draft horses. PMU farmers want to produce smaller foals to reduce feed costs therefore most Premarin mares are bred to lighter saddle horse stallions rather than draft stallions. The draft cross foals that result are poorly bred and while often make good riding horses are not in great demand by the general riding public. As with cross bred dogs (mutts), there are more cross bred horses than there is demand for them. Some PMU farms attempt to increase the value of their foals by breeding their production mares with good quality and/or "colored" stallions (stallions which are likely to produce interestingly colored offspring like paints or palominos). Invariably, however, most PMU foals--colored or not--end up bound for slaughter houses to become horse meat for human or animal consumption.