Effects in post-menopausal women of transdermal estrogen associated with progestin upon the removal from the plasma of a microemulsion that resembles low-density lipoprotein (LDL).
OBJECTIVE
To evaluate the effects of transdermal estradiol and medroxyprogesterone acetate (MPA) treatment on the removal from the plasma of a cholesterol-rich microemulsion (LDE) that roughly resembles low-density lipoprotein (LDL) structure and that binds to LDL receptors.


METHODS
Ten healthy post-menopausal women were studied before and after 3-month treatment with transdermal estradiol in the following dosages administered every 3.5 days: 25, 50, 50, 100, 100, 50, 50 and 25 microg. From the 15th to the 21st day and from the 22nd to the 28th day of estrogen treatment, respectively, 10 and 5 mg q.d. MPA per oral were associated to the transdermal estrogen. The emulsion labeled with 14C-cholesteryl oleate was injected after 12 h fasting and its fractional catabolic rate (FCR) was calculated from the plasma decaying curves of the isotope.


RESULTS
Treatment reduced LDL-cholesterol levels by 8% only (149.0 +/- 36.0 mg/dl, 138.0 +/- 27.0 mg/dl; P = 0.046), but the FCR of LDE expressed in medians (25%; 75%) increased from 0.0054 (0.003; 0.052) h(-1) to 0.021 (0.009; 0.10) h(-1), P = 0.002.


CONCLUSIONS
The association used in this study so as to mimic the increasing-decreasing pattern of the hormonal ovarian production reduced modestly LDL-cholesterol levels but pronouncedly increased the lipoprotein removal as tested by LDE FCR.
Melo
Nilson R
NR
Department of Gynecology, University of São Paulo Medical School Hospital, São Paulo, Brazil.
Latrilha
Maria C
MC
Santos
Raul D
RD
Pompei
Luciano M
LM
Maranhão
Raul C
RC
D000279:Administration, Cutaneous; D000284:Administration, Oral; D002788:Cholesterol Esters / Q000494:pharmacology; D008078:Cholesterol, LDL / Q000097:blood / Q000187:drug effects*; D004655:Emulsions / Q000494:pharmacology; D004958:Estradiol / Q000008:administration & dosage*; D015914:Estrogen Replacement Therapy; D005260:Female; D006801:Humans; D006937:Hypercholesterolemia / Q000097:blood*; D017258:Medroxyprogesterone Acetate / Q000008:administration & dosage*; D008875:Middle Aged; D017698:Postmenopause; D016896:Treatment Outcome
D002788:Cholesterol Esters; D008078:Cholesterol, LDL; D004655:Emulsions; C014409:cholesteryl oleate; D004958:Estradiol; D017258:Medroxyprogesterone Acetate