Effect of dexamethasone as an inhibitor of implantation and embryo development in rat; lysosomal role.
In order to learn the mechanism of action of dexamethasone administration as an efficient inhibitor of estrogen activity in different tissues, the subcellular enzymatic distribution of two lysosomal enzymes: acid phosphatase (E.C.3.1.3.2.) and beta glucuronidase (E.C.3.2.1.3.1.) were measured. The rats were treated during preimplantation with dexamethasone (0.8 mg on days 3 and 4) or saline (controls). In the control group, the nuclear activity of lysosomal enzymes was significantly less in the implantation site tissue than in the treated group (p < 0.05). There were no modifications on the undecidualized endometrium under the steroid treatment. The lysosomal subfraction showed an opposite response. The steroid treatment produced an increase of activity in the decidualized tissue (1.9 +/- 0.4 to 4.9 +/- 0.4) while the nuclear enzymatic activity decreased under treatment; and simultaneously, the embryonic development was 100% abolished. From the results presented herein, it is proposed that the inhibitory effect of dexamethasone upon implantation is due to an inadequate biochemical differentiation at the implantation site, related to the inhibition of lysosomal movement toward the nucleus, and consequently to lysosomal enzymatic release and metabolic role.
Hicks
J J
JJ
Unidad de Investigación Médica, Bioquimica Hospital de Especialidades, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico D.F. Mexico.
Duran-Reyes
G
G
Díaz-Flores
M
M
D000135:Acid Phosphatase / Q000032:analysis; D000818:Animals; D003907:Dexamethasone / Q000494:pharmacology*; D010064:Embryo Implantation / Q000187:drug effects* / Q000502:physiology; D005314:Embryonic and Fetal Development / Q000187:drug effects* / Q000502:physiology; D004717:Endometrium / Q000187:drug effects; D004965:Estrogen Antagonists / Q000494:pharmacology; D005260:Female; D005966:Glucuronidase / Q000032:analysis; D008247:Lysosomes / Q000201:enzymology / Q000502:physiology*; D011247:Pregnancy; D051381:Rats
D004965:Estrogen Antagonists; D003907:Dexamethasone; D000135:Acid Phosphatase; D005966:Glucuronidase