TY - JOUR
T1 - Effects of prostaglandins and oestradiol-17b on oxytocin binding in cultured bovine luteal cells
AU - Okuda, Kiyoshi
AU - Uenoyama, Yoshihisa
AU - Miyamoto, Akio
AU - Okano, Akira
AU - Schweigert, Florian J.
AU - Schams, Dieter
N1 - Funding Information:
This research was supported by the German Ministry for Science and Technology (Grant 01KY9104), Bio Media Program from the Ministry of Agriculture, Forestry and Fisheries of Japan (BMP-95-V-2-2), and Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture of Japan (No. 05806039) to K.O. We are most grateful to Teikoku Hormone MFG, Tokyo, Japan for the generous gift of synthetic oxytocin. A.M. was supported by the Japanese Society for the Promotion of Science (JSPS).
PY - 1995
Y1 - 1995
N2 - The aim of the investigation was to evaluate the possible action of prostaglandins (PGs) and oestradiol-17b (oestradiol) on the specific binding for oxytocin in bovine luteal cells. Cultured cells of bovine corpora lutea at the mid-luteal stage (Day 8-12 of the oestrous cycle) were examined for the presence of oxytocin receptors by a radioreceptor assay using the 125l-labelled oxytocin antagonist [d(CH2)s, Tyr(Me)2, Thr4, Tyr-NH29]-vasotocin (125I-OVT) as a ligand. The cells were cultured for 48 h in total. In the final 15 h of culture, the luteal cells were exposed to varying concentrations of PGF20 PGE2, PGI2 and/or oestradiol. After culture, the cells were incubated with 37000 dpm (0-5 nM) 125I-OVT with or without 100 nM of unlabelled oxytocin. PGF2a, at 10-8 M and 10-7 m, stimulated the specific binding for oxytocin to levels as high as 128% of controls (P<001); by contrast, PGE2, PGI2 or oestradiol had no effect on oxytocin binding. Scatchard analysis revealed that the concentration of oxytocin receptors was increased (P< 0 05) from 6-7fmol mg-1 DNA to 8-4fmol mg-1 DNA by stimulation with 10-7 M of PGF2, without changing the binding affinity. No further increase in the specific binding was observed when PGF2a was used in combination with PGE2, PGI2 or oestradiol at a concentration of KT7 m. Addition of indomethacin (28 mm) resulted in the inhibition of PGF^ secretion, coinciding with a significant decrease in oxytocin binding (P<0 01). However, addition of arachidonic acid (100 p.m) caused a significant increase in the secretion of PGF2a and the specific binding for oxytocin concomitantly (P < 0.05). When the protein kinase C (PKC) activity of the luteal cells was inactivated by preincubating cells for 13 h with 1 mM phorbol 12-myristate 13-acetate before PGF2a stimulation, the specific binding for oxytocin was not affected by PGFoa stimulation (10-7 m) in the final 15 h of culture. These data suggest that PGF2a may be one of the potent regulators for luteal oxytocin receptors in a paracrine and/or autocrine manner, and that its action is mediated by PKC.
AB - The aim of the investigation was to evaluate the possible action of prostaglandins (PGs) and oestradiol-17b (oestradiol) on the specific binding for oxytocin in bovine luteal cells. Cultured cells of bovine corpora lutea at the mid-luteal stage (Day 8-12 of the oestrous cycle) were examined for the presence of oxytocin receptors by a radioreceptor assay using the 125l-labelled oxytocin antagonist [d(CH2)s, Tyr(Me)2, Thr4, Tyr-NH29]-vasotocin (125I-OVT) as a ligand. The cells were cultured for 48 h in total. In the final 15 h of culture, the luteal cells were exposed to varying concentrations of PGF20 PGE2, PGI2 and/or oestradiol. After culture, the cells were incubated with 37000 dpm (0-5 nM) 125I-OVT with or without 100 nM of unlabelled oxytocin. PGF2a, at 10-8 M and 10-7 m, stimulated the specific binding for oxytocin to levels as high as 128% of controls (P<001); by contrast, PGE2, PGI2 or oestradiol had no effect on oxytocin binding. Scatchard analysis revealed that the concentration of oxytocin receptors was increased (P< 0 05) from 6-7fmol mg-1 DNA to 8-4fmol mg-1 DNA by stimulation with 10-7 M of PGF2, without changing the binding affinity. No further increase in the specific binding was observed when PGF2a was used in combination with PGE2, PGI2 or oestradiol at a concentration of KT7 m. Addition of indomethacin (28 mm) resulted in the inhibition of PGF^ secretion, coinciding with a significant decrease in oxytocin binding (P<0 01). However, addition of arachidonic acid (100 p.m) caused a significant increase in the secretion of PGF2a and the specific binding for oxytocin concomitantly (P < 0.05). When the protein kinase C (PKC) activity of the luteal cells was inactivated by preincubating cells for 13 h with 1 mM phorbol 12-myristate 13-acetate before PGF2a stimulation, the specific binding for oxytocin was not affected by PGFoa stimulation (10-7 m) in the final 15 h of culture. These data suggest that PGF2a may be one of the potent regulators for luteal oxytocin receptors in a paracrine and/or autocrine manner, and that its action is mediated by PKC.
KW - Corpus luteum
KW - Oxytocin receptor
KW - Prostaglandin F2a
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U2 - 10.1071/RD9951045
DO - 10.1071/RD9951045
M3 - Article
C2 - 8848569
AN - SCOPUS:0029416857
SN - 1031-3613
VL - 7
SP - 1045
EP - 1051
JO - Australian journal of scientific research. Ser. B: Biological sciences
JF - Australian journal of scientific research. Ser. B: Biological sciences
IS - 5
ER -