Kazuhiro Ogura

Gestational changes of glucose transporter gene expression in the mouse placenta and decidua

Glucose is required for fetal development and energy metabolism. The glucose transfer from maternal circulation to fetus, in which glucose transporter (GLUT) should play an important role, is fundamental in the utero-placental-fetal system. In this study, the gestational changes of GLUTI and GLUT3 mRNA level in the mouse placenta and decidua were analyzed by Northern blot analysis. The levels of GLUT1 mRNA in the mouse placenta and decidua increased as gestational day proceeded. Although the level of GLUT3 mRNA in the decidua slightly decreased as pregnancy proceeded, there was a switch in size of a major band of GLUT3 from 4.1 kb to 2.7 kb in the mouse placenta detected by Northern blot analysis. These findings suggest the presence of a difference in the gestational modulation of the level of GLUT1 and GLUT3 in the uteroplacental system.

Messenger RNA differential display reverse-transcriptase-polymerase-chain-reaction analysis of a progestogen-suppressive gene in a human endometrial-cancer cell line.

Progestogen suppresses the progression of endometrial cancer and has an important effect on the secretory change of human endometrium. We characterized the progestogen‐induced alterations of gene expression in a human endometrial‐cancer cell line using a mRNA differential‐display reverse‐transcriptase‐polymerase‐chain‐reaction (DDRT‐PCR) method. After 5‐day incubation of Ishikawa endometrial‐cancer cells, with or without 100 nM medroxyprogesterone acetate (MPA), total RNA was isolated from confluent cells. We identified 8 candidate genes by mRNA differential display by screening up to approximately 3,000 mRNA species. Among these, 2 genes named T21A and T21B showed a decrease in mRNA by MPA treatment when analyzed by Northern blot. Nucleotide sequence showed that clone T21A was part of human mitochondrial short‐chain enoyl‐CoA hydratase cDNA. The other clone, T21B, showed no homology with any known nucleotide sequences. Northern‐blot analysis using T21A and T21B clones as probes showed a decrease in mRNA in human endometrium from the luteal stage, with high serum estradiol and progesterone levels, as compared with that from the early follicular stage, with low serum estradiol and progesterone levels, and that from the pre‐ovulatory stage with high serum estradiol and low progesterone levels. These findings suggest that mRNA DDRT‐PCR could be used to identify the candidate genes regulated by progestogen in human endometrial cancer and in normal human endometrium. Int. J. Cancer 78:125–129, 1998.© 1998 Wiley‐Liss, Inc.

Transforming growth factor-α regulates subpopulation of giant cells which secrete mouse placental lactogen-I (mPL-I) and/or mPL-II at midpregnancy

The aim of this study was to determine whether transforming growth factor-α (TGF-α) regulates expression of mouse placental lactogen-I (mPL-I) and mPL-II at midpregnancy in vitro. Treatment of placental cells from day 9 of pregnancy with TGF-α resulted in stimulation of mPL-I secretion and inhibition of mPL-II secretion in a time- and dose-dependent manner without changing the amount of newly synthesized trichloroacetic acid precipitable proteins and cell viability. Moreover, TGF-α increased the intra-cellular mPL-I concentration and immuno-precipitable newly synthesized mPL-I concentration both in the medium and cells. TGF-α increased the number of cells containing only mPL-I and cells containing both mPL-I and mPL-II, but decreased that of the cells containing only mPL-II assessed by double immunocytochemistry. TGF-α increased the number of cells releasing only mPL-I but decreased the number of cells releasing only mPL-II, however TGF-α did not affect the number of cells releasing both mPL-I and mPL-II assessed by sequential reverse hemolytic plaque assay (RHPA). TGF-α decreased the expression of mPL-II mRNA, but did not change the expression of mPL-I mRNA. In situ hybridization for epidermal growth factor receptor (EGF-R) after RHPA for mPL-I indicated that giant cells releasing mPL-I express EGF-R mRNA. These findings suggest that TGF-α regulates the subpopulation of giant cells which produces and releases mPL-I and mPL-II and it results in an increase of mPL-I secretion and decrease of mPL-II secretion, and suggests possible post-transcriptional stimulation of mPL-I secretion and transcriptional inhibition of mPL-II secretion by TGF-α. Giant cells releasing mPL-I express EGF-R mRNA, suggesting direct regulation of giant cell differentiation by EGF and TGF-α at midpregnancy.