Effect of the antiestrogen ethamoxytriphetol (MER-25) on placental low density lipoprotein uptake and degradation in baboons

Journal Article · Sun May 01 04:00:00 EDT 1988 · Endocrinology; (United States)

DOI:https://doi.org/10.1210/endo-122-5-2019· OSTI ID:7070239

Henson, M C; Babischkin, J S; Pepe, G J; Albrecht, E D

The present study determined if the decline in placental progesterone (P4) production that results from administration of the antiestrogen ethamoxytriphetol (MER-25) to pregnant baboons results from a change in placental low density lipoprotein (LDL) uptake and/or degradation. Pregnant baboons (Papio anubis) were untreated (n = 10) or received MER-25 (25 mg/kg BW, orally; n = 10) daily on days 140-170 of gestation (term, 184 days). Placentas were removed by cesarean section on day 170 of gestation, and villous tissue was dispersed with 0.1% collagenase at 37 C for 40 min. Placental cells (10(6)) were incubated in medium 199 (pH 7.2) for 12 h at 37 C with increasing amounts (5-100 micrograms) of (125I)LDL, with or without a 100-fold excess of unlabeled baboon LDL. Mean (+/- SE) peripheral serum P4 concentrations on days 140-170 of gestation were 51% lower (P less than 0.01) in MER-25-treated (5.7 +/- 0.3 ng/ml) than in untreated (11.6 +/- 0.5 ng/ml) baboons. The uptake of LDL was 56% lower (P less than 0.01) in placental cells from antiestrogen-treated (6.3 +/- 1.6 ng/micrograms cell protein) than in those from untreated (14.4 +/- 1.9 ng/micrograms cell protein) baboons. The dissociation constants for placental LDL uptake, as assessed by Scatchard analysis, however, were similar in untreated (0.80 microgram/ml) and MER-25-treated (0.76 microgram/ml) animals. The amount of (125I)LDL concomitantly degraded by cells from baboons that received MER-25 was 54% of that degraded by cells from untreated controls. The relative decline in LDL degradation by cells of antiestrogen-treated baboons was proportionate to the decline in overall LDL uptake. The results indicate, therefore, that antiestrogen treatment decreased the amount of placental LDL uptake, but did not change the affinity for the lipoprotein.

• Research Organization: Univ. of Maryland School of Medicine, Baltimore (USA)
• OSTI ID: 7070239
• Journal Information: Endocrinology; (United States), Journal Name: Endocrinology; (United States) Vol. 122:5; ISSN ENDOA
• Country of Publication: United States
• Language: English

Related Subjects

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59 BASIC BIOLOGICAL SCIENCES
ANIMALS
APES
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOSYNTHESIS
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ESTROGENS
FETAL MEMBRANES
HORMONE ANTAGONISTS
HORMONES
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KETONES
KINETICS
LIPIDS
LIPOPROTEINS
MAMMALS
MEMBRANES
METABOLISM
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PLACENTA
PREGNANCY
PREGNANES
PRIMATES
PROGESTERONE
PROTEINS
RADIOISOTOPES
REACTION KINETICS
STEROID HORMONES
STEROIDS
SYNTHESIS
TRACER TECHNIQUES
UPTAKE
VERTEBRATES