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Localisation and expression of insulin-like growth factor I receptor protein in human placental syncytiotrophoblast
Abstracts
L O C A L I S A T I O N AND EXPRESSION OF I N S U L I N - L I K E G R O W T H FACTOR I R E C E P T O R P R O T E I N IN H U M A N P L A C E N T A L S Y N C Y T I O T R O P H O B L A S T Elizabeth A. Cowley, Thomas Jansson and Nicholas P. Illsley, Department of Obstetrics and Gynecology and Reproductive Sciences, University of California, San Francisco, CA 94143-0550. Insulin-like growth factors (IGFs) have been implicated as regulatory factors during human fetal development. In addition, IGFs' are also thought to be important in placental growth and transport, and while human placental tissue is known to express IGF-I receptor mRNA and protein, the precise location of this receptor has not been described. Vesicles were prepared from human term placental microvillous (MVM) and basal (BM) membranes, and immunoblotting performed using a polyclonal antibody to the IGF-I receptor. Immunoreactive bands were detected by chemiluminescence and quantified using densitometry. The receptor was detected on both syncytiotrophoblast membranes. Receptor densities were consistently higher on the MVM than the BM, (1.7 fold increase; n=12). Further, MVM and BM from second trimester (16 to 21 weeks) and term intrauterine growth retarded (IUGR) placentae were also examined. Second trimester tissue (n=7) revealed lower IGF-I receptor densities on both the MVM (-50% of term values), and BM (-25% of term values). Receptor expression in IUGR placentae, however, did not appear to differ significantly from normal term tissue (n=6). In conclusion, we have detected IGF-I receptors on both the microvillous and basal surfaces of human placental syncytial cells, and that the expression of these receptors increases with gestational age from second trimester to term. This suggests that placental growth and/or function may be regulated by IGF-I produced by the fetus as well as the decidua, and that IGF-I may play a significant role in regulating placental function in late gestation.
IMMUNOCYTOCHEMICAL EXPRESSION PATTERNS OF CARBONIC ANHYDRASE ISOENZYMES IN HUMAN PLACENTA, CORD AND MEMBRANES. C. Crescimanno 1, J. MOhlhauser 1, M. Castellucci1, H. Rajaniemi 2, S. Parkkila 2 and P. Kaufmann ~, Department of Anatomy ~, Technical University of Aachen, FRG and Department of Anatomy2, University of Oulu, Finland. Carbonic anhydrase catalyzes the hydration of CO~ and the dehydration of H2CO3. It plays an important role in regulating the electrolyte and the acid-base balance in most mammalian tissues. The Iocalizations of human and rat carbonic anhydrase isoenzymes HCA I, HCA II and rat CA II have been investigated by immunofluorescence in human umbilical cord, chorion laeve and placenta from first trimester and term pregnancies. HCA I was found in fetal villous endothelium while HCA II and rat CA II immunoreactMty was primarily present in the basal part of villous syncytiotrophoblast. The highest immunoreactivities for all three antibodies were detected In the amnionic epithelium of the chorionlc plate, the membranes and the cord. Western blots support these findings. These results suggest that the amnlonic epithelium is involved in the processes of bicarbonate removal from the amnionic fluid, thus regulating its pH.
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L O C A L I S A T I O N AND EXPRESSION OF I N S U L I N - L I K E G R O W T H FACTOR I R E C E P T O R P R O T E I N IN H U M A N P L A C E N T A L S Y N C Y T I O T R O P H O B L A S T Elizabeth A. Cowley, Thomas Jansson and Nicholas P. Illsley, Department of Obstetrics and Gynecology and Reproductive Sciences, University of California, San Francisco, CA 94143-0550. Insulin-like growth factors (IGFs) have been implicated as regulatory factors during human fetal development. In addition, IGFs' are also thought to be important in placental growth and transport, and while human placental tissue is known to express IGF-I receptor mRNA and protein, the precise location of this receptor has not been described. Vesicles were prepared from human term placental microvillous (MVM) and basal (BM) membranes, and immunoblotting performed using a polyclonal antibody to the IGF-I receptor. Immunoreactive bands were detected by chemiluminescence and quantified using densitometry. The receptor was detected on both syncytiotrophoblast membranes. Receptor densities were consistently higher on the MVM than the BM, (1.7 fold increase; n=12). Further, MVM and BM from second trimester (16 to 21 weeks) and term intrauterine growth retarded (IUGR) placentae were also examined. Second trimester tissue (n=7) revealed lower IGF-I receptor densities on both the MVM (-50% of term values), and BM (-25% of term values). Receptor expression in IUGR placentae, however, did not appear to differ significantly from normal term tissue (n=6). In conclusion, we have detected IGF-I receptors on both the microvillous and basal surfaces of human placental syncytial cells, and that the expression of these receptors increases with gestational age from second trimester to term. This suggests that placental growth and/or function may be regulated by IGF-I produced by the fetus as well as the decidua, and that IGF-I may play a significant role in regulating placental function in late gestation.
IMMUNOCYTOCHEMICAL EXPRESSION PATTERNS OF CARBONIC ANHYDRASE ISOENZYMES IN HUMAN PLACENTA, CORD AND MEMBRANES. C. Crescimanno 1, J. MOhlhauser 1, M. Castellucci1, H. Rajaniemi 2, S. Parkkila 2 and P. Kaufmann ~, Department of Anatomy ~, Technical University of Aachen, FRG and Department of Anatomy2, University of Oulu, Finland. Carbonic anhydrase catalyzes the hydration of CO~ and the dehydration of H2CO3. It plays an important role in regulating the electrolyte and the acid-base balance in most mammalian tissues. The Iocalizations of human and rat carbonic anhydrase isoenzymes HCA I, HCA II and rat CA II have been investigated by immunofluorescence in human umbilical cord, chorion laeve and placenta from first trimester and term pregnancies. HCA I was found in fetal villous endothelium while HCA II and rat CA II immunoreactMty was primarily present in the basal part of villous syncytiotrophoblast. The highest immunoreactivities for all three antibodies were detected In the amnionic epithelium of the chorionlc plate, the membranes and the cord. Western blots support these findings. These results suggest that the amnlonic epithelium is involved in the processes of bicarbonate removal from the amnionic fluid, thus regulating its pH.
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