Progesterone production in early pregnancy.
Before and after elective abortion, progesterone (P) and human chorionic gonadotropin (hCG) levels were determined to describe the origin of P and to investigate the relationship between levels of hCG and luteal steroidogenesis. After abortion, P levels initially fell rapidly, followed by a slower decline. The initial fall in P levels and the remaining level of P 3 hours after abortion were taken to represent the removal of P that originated from the trophoblast and the continuing P contribution by the corpus luteum (CL), respectively. Using this analysis, we conclude: (1) P production by the CL is sustained well into the second trimester of pregnancy and (2) increasing trophoblastic production of P allows the pregnancy progressive independence from the CL.
Nakajima
S T
ST
Department of Obstetrics and Gynecology, University of Vermont College of Medicine, Burlington 05405.
Nason
F G
FG
Badger
G J
GJ
Gibson
M
M
D000328:Adult; D006063:Chorionic Gonadotropin / Q000097:blood; D003338:Corpus Luteum / Q000378:metabolism; D005260:Female; D006801:Humans; D011247:Pregnancy / Q000378:metabolism*; D011261:Pregnancy Trimester, First / Q000378:metabolism; D011262:Pregnancy Trimester, Second / Q000378:metabolism; D011374:Progesterone / Q000096:biosynthesis*; D014327:Trophoblasts / Q000378:metabolism
D006063:Chorionic Gonadotropin; D011374:Progesterone