- Email: [email protected]
Antilipolytic hormones stimulate the secretion of HCG in cultivated trophoblasts via a pathway involving protein kinase C
508
Placenta (1989), Vol. IO
molecular marker of I ,25D action) was found in transblots of SDS-PAGE separated placental proteins when incubated with [4JCa]. Collectively, these in vitro and in vivo data are consistent with the placenta being a target site for the action of 1,25D in the sheep.
ANTILIPOLYTIC HORMONES STIMULATE THE SECRETION OF hCG IN CULTIVATED TROPHOBLASTS VIA A PATHWAY INVOLVING PROTEIN KINASE C G. Desoye, B. Schmon, I. Andiel, R. Michlmayer, G. DohP, M. Hartmanna & A. Blaschitz” (Department of Obstetrics and Gynaecology and ‘Institute of Histology and Embryology, University of Graz, A-8036 Graz, Austria) The present study was undertaken in order to investigate if insulin (I) and nicotinic acid (NA) affect the secretion of hCG and if this occurs via a common pathway involving protein kinase C (pkC). Cytotrophoblasts were isolated from human term placenta following established protocols. Every 24 h the culture media (D-MEM)-which had or had not been supplemented with the reagents under study-were changed during 8 days and the concentrations of alpha-hCG (a-hCG), hCG and hPL were measured by RIA. Viability of cells was assessed by dye exclusion and glucose consumption. Both I and NA increased the total amount of secreted a-hCG and hCG after 8 days in a concentration dependent manner. hPL was unaffected by I and decreased by NA, respectively. Monoclonal anti-sinsulin-receptor antibodies mimicked I effects, suggesting that I effects are mediated by I receptors. Supplementation of maximally stimulating concentrations of either hormones plus varying concentrations of an inhibitor of pkC reduced the secretion of a-hCG and hCG to as low as 30 per cent of control (D-MEM). hPL levels were higher (I) or equal (NA) compared to control. Phorboldibutyrate, a stimulator of pkC, increased in a concentration dependent manner a-hCG and hCG concentrations by up to 50 per cent and 40 per cent, respectively, whereas it did not alter hPL levels. Generally, the time course of hormone secretion and of the formation of syncytia was unaffected. The data indicate: (I) I and NA stimulate hCG secretion by a common mechanism involving pkC, (2) this mechanism is not specific for I and NA but may also apply to other stimulators of pkC, like adenosin, which is generally supplemented to D-MEM, and (3) hCG and hPL secretion are differently regulated.
THE ROLE OF EGF IN hCG SECRETION AND TROPHOBLAST DIFFERENTIATION IN THE FIRST TRIMESTER E. R. Barnea, D. Feldman & M. Kaplan (Feto-Placental Endocrin. Unit, Rappaport Institute, Technion, Haifa, Israel) The role of EGF in the placenta has been previously addressed. At term and midterm it stimulated hCG secretion and induced cellular differentiation. The information on the role of EGF in the first trimester placenta (FTP) is, however, scant. Here we investigated the effect of EGF on FTP in three different in vitro models. Placental tissue obtained from elective pregnancy terminations (7-10 weeks) was cleared of blood with 0.9 per cent NaCl and rinsed with DMEM containing I per cent antibiotics. Cells were dislodged with trypsin/DNAse and cultured with DMEM, 5 per cent FCS for 1-50 days with or without 10+200 ng/ml EGF. The
Placenta (1989), Vol. IO
molecular marker of I ,25D action) was found in transblots of SDS-PAGE separated placental proteins when incubated with [4JCa]. Collectively, these in vitro and in vivo data are consistent with the placenta being a target site for the action of 1,25D in the sheep.
ANTILIPOLYTIC HORMONES STIMULATE THE SECRETION OF hCG IN CULTIVATED TROPHOBLASTS VIA A PATHWAY INVOLVING PROTEIN KINASE C G. Desoye, B. Schmon, I. Andiel, R. Michlmayer, G. DohP, M. Hartmanna & A. Blaschitz” (Department of Obstetrics and Gynaecology and ‘Institute of Histology and Embryology, University of Graz, A-8036 Graz, Austria) The present study was undertaken in order to investigate if insulin (I) and nicotinic acid (NA) affect the secretion of hCG and if this occurs via a common pathway involving protein kinase C (pkC). Cytotrophoblasts were isolated from human term placenta following established protocols. Every 24 h the culture media (D-MEM)-which had or had not been supplemented with the reagents under study-were changed during 8 days and the concentrations of alpha-hCG (a-hCG), hCG and hPL were measured by RIA. Viability of cells was assessed by dye exclusion and glucose consumption. Both I and NA increased the total amount of secreted a-hCG and hCG after 8 days in a concentration dependent manner. hPL was unaffected by I and decreased by NA, respectively. Monoclonal anti-sinsulin-receptor antibodies mimicked I effects, suggesting that I effects are mediated by I receptors. Supplementation of maximally stimulating concentrations of either hormones plus varying concentrations of an inhibitor of pkC reduced the secretion of a-hCG and hCG to as low as 30 per cent of control (D-MEM). hPL levels were higher (I) or equal (NA) compared to control. Phorboldibutyrate, a stimulator of pkC, increased in a concentration dependent manner a-hCG and hCG concentrations by up to 50 per cent and 40 per cent, respectively, whereas it did not alter hPL levels. Generally, the time course of hormone secretion and of the formation of syncytia was unaffected. The data indicate: (I) I and NA stimulate hCG secretion by a common mechanism involving pkC, (2) this mechanism is not specific for I and NA but may also apply to other stimulators of pkC, like adenosin, which is generally supplemented to D-MEM, and (3) hCG and hPL secretion are differently regulated.
THE ROLE OF EGF IN hCG SECRETION AND TROPHOBLAST DIFFERENTIATION IN THE FIRST TRIMESTER E. R. Barnea, D. Feldman & M. Kaplan (Feto-Placental Endocrin. Unit, Rappaport Institute, Technion, Haifa, Israel) The role of EGF in the placenta has been previously addressed. At term and midterm it stimulated hCG secretion and induced cellular differentiation. The information on the role of EGF in the first trimester placenta (FTP) is, however, scant. Here we investigated the effect of EGF on FTP in three different in vitro models. Placental tissue obtained from elective pregnancy terminations (7-10 weeks) was cleared of blood with 0.9 per cent NaCl and rinsed with DMEM containing I per cent antibiotics. Cells were dislodged with trypsin/DNAse and cultured with DMEM, 5 per cent FCS for 1-50 days with or without 10+200 ng/ml EGF. The