Raloxifene, DHEA, and Osteoporosis
Associated Press, Sept 12: "A new drug could give aging women all the
benefits of estrogen replacement, such as stronger bones, but have fewer
side effects, according to a study released Thursday. The study
suggests the drug, an "anti-estrogen" called raloxifene, helps increase
bone mass and reduce blood cholesterol levels like estrogen, said Dr.
Edward Lufkin, the study's lead author."
I suggest all raloxifene may be doing is increasing production of the
natural, adrenal hormone, DHEA, a commonly available, cheap hormone.
This is easily demonstrated.
A single injection of raloxifene significantly increases the production
of the pituitary hormone, prolactin (Prostate 1993;23(3):245-262).
Prolactin is not only specific for stimulating DHEA (Endocrinology 1985;
117: 1968), but prolactin stimulates DHEA more than the usual hormone,
ACTH, thought to stimulate the adrenal glands (American Journal of
Obstetrics and Gynecology 1987; 156: 1275).
Osteoporosis is the loss of bone mineral (BMD) density in aging.
"Estrogen" is usually given credit for helping with BMD in aging women.
However, "estrogen" is a combination of compounds that includes
estradiol (E2) and estrone (E1). It has been proven that "chronic
administration of estrone significantly enhanced the bone mineral
density of femur in aged animals" (In Vivo 1996 Jul;10(4):455-457). The
connection of estrone with DHEA is that "DHEA, is converted to E1 in
osteoblasts [[the primary bone-forming cells]
and important to maintain
BMD in the 6 to 7th decade, after menopause." (J Steroid Biochem Mol
Biol 1995 Jun;53(1-6):165-174).
DHEA begins to naturally decline around age twenty and reaches very low
levels in old age, when osteoporosis occurs. I suggest that raloxifene
is stimulating production of DHEA, which is converted into estrone, by
bone-forming cells. This estrone causes the osteoblasts to increase the
bone mineral density that was lost in old age, because of the loss of
DHEA. Raloxifene also reduces cholesterol levels. Again, this is
another of the effects of DHEA. When given to 60- to 70-year-old women,
DHEA causes a decrease in total cholesterol (J Endocrinol 1996 Sep;150
It may well be that all raloxifene is doing is increasing DHEA in women,
whose DHEA has declined to very low levels. Another study found that:
"DHEA in appropriate replacement doses appears to have remedial effects
with respect to its ability to induce an anabolic growth factor,
increase muscle strength and lean body mass, activate immune function,
and enhance quality of life in aging men and women, with no significant
adverse effects." (Annals of the New York Academy of Science 1995; 774:
128). Perhaps before physicians start prescribing raloxifene, they
should consider DHEA.