Vol. 276, Issue 2, E384-E389, February 1999
Pre-
-HDL stimulates placental lactogen release from human
trophoblast cells
Stuart
Handwerger1,
Geeta
Datta3,
Brian
Richardson1,
Carrie M.
Schmidt1,
Tariq
Siddiqi2,
Lisa
Turzai1, and
G. M.
Anantharamaiah3
Departments of 1 Pediatrics and
2 Obstetrics and Gynecology,
University of Cincinnati College of Medicine, Cincinnati, Ohio 45229;
and 3 Atherosclerosis Research
Unit, Department of Medicine, University of Alabama, Birmingham,
Alabama 35294
To examine whether
pre-
-high-density lipoprotein (HDL) may be involved in regulation of
human placental lactogen (hPL) release, pre--HDL was isolated from
term pregnancy serum, and the effect of purified pre--HDL on hPL
release from trophoblast cells was examined after 1 h of exposure.
Pre--HDL stimulated a dose-dependent increase in hPL release with
half-maximal stimulation at a dose of 300-400 µg/ml, which is
within the normal physiological range during pregnancy. Analysis of
pre--HDL and 
-HDL in serum from pregnant women at different
stages of gestation (determined by Western blot analysis) indicated
that the pre--HDL-to--HDL ratio increased linearly after the 10th
week of gestation (r = 0.88, P < 0.001), reaching a maximum
sixfold greater than that of nonpregnant women. The increase in serum
pre--HDL during pregnancy paralleled that of plasma hPL
concentrations (r = 0.93, P < 0.001). Two-dimensional electrophoresis indicated that the increase in pre--HDL was due primarily to an increase in
pre-1-HDL and
pre-2-HDL, two of the three
forms of pre--HDL present in blood. These results suggest a role for
pre--HDL in the regulation of hPL expression during pregnancy.
lipoproteins; placenta; pregnancy
