The liver is an estrogen-responsive organ and the administration of estrogens in humans
increases the hepatic synthesis of many proteins. The existence of a circadian rhythm
of estrogen receptors in the liver has been proved by different authors. We studied
the presence of a different responsiveness of the human liver to the estrogens in
two groups of post-menopausal women by evaluating the changes in ceruloplasmin serum
level. Conjugated equine estrogens were administered at different times (A: 8 a. m.
and B: 8 p. m.). The replacement therapy increased ceruloplasmin serum levels both
in group A and B, but the increase was higher in group B than in group A. These data
reflect indirectly the presence of a circadian rhythm of hepatic responsiveness to
the estrogens.
Ceruloplasmin - Sex Steroid Hormones - Estrogen Therapy - Circadian Rhythm
