Abstract
Two forms of placental lactogen (PL), designated PL-I and PL-II, have been reported in the serum of pregnant rats PL-I was secreted during mid-pregnancy and PL-II was secreted near term. In the present study, we found that two distinct forms with PL-like activity were secreted into the blood during mid-pregnancy. Serum from day-12 pregnant rats was subjected to high-performance liquid chromatography (HPLC) gel-filtration (TSK-G3000SswXL column), and PL activity was assayed by radioreceptor assay using 125I-labeled rat PRL and hepatocyte plasma membrane from pregnant rats. HPLC-gel filtration separated the PL activity into two peaks with mol wt of 55-60 K and 45-50 K, as estimated by reference to the elution volume of standard proteins. We tentatively designated these peaks PL-α and PL-β, respectively. Considering these mol wt, PL-β seemed to be identical to PL-I. mRNA was extracted from samples of placenta obtained each day from day 8 to day 12 of pregnancy and analyzed by means of a translation system involving micro-injection into Xenopus oocytes. The time of appearance of the mRNAs corresponding to PL-α and PL-β did not correspond and differed according to the day of pregnancy, suggesting that there are individual mRNAs for each PL in rat placenta. Treatment of PL-α and PL-β with peptide: N-glycosidase F completely abolished the binding activity to their receptors. Also since they were sensitive to glycosidases such as endoglycosidase H, endoglycosidase F and neuraminidase, these PLs were considered to possess N-linked glycoresidue(s) and to be sialylated. Based on the results, there are two distinct PLs, which are secreted at mid-pregnancy, are glycosylated and have different mRNAs.
| Original language | English |
|---|---|
| Pages (from-to) | 533-540 |
| Number of pages | 8 |
| Journal | Endocrinologia Japonica |
| Volume | 38 |
| Issue number | 5 |
| Publication status | Published - 1991 |
| Externally published | Yes |
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Keywords
- glycoprotein
- placenta
- placental lactogen-α
- placental lactogen-β
- pregnancy
ASJC Scopus subject areas
- Endocrinology
Cite this
Two distinct placental lactogen-like substances in serum during mid-pregnancy in the rat. / Furuyama, N.; Shiota, K.; Takahashi, M.
In: Endocrinologia Japonica, Vol. 38, No. 5, 1991, p. 533-540.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Two distinct placental lactogen-like substances in serum during mid-pregnancy in the rat
AU - Furuyama, N.
AU - Shiota, K.
AU - Takahashi, M.
PY - 1991
Y1 - 1991
N2 - Two forms of placental lactogen (PL), designated PL-I and PL-II, have been reported in the serum of pregnant rats PL-I was secreted during mid-pregnancy and PL-II was secreted near term. In the present study, we found that two distinct forms with PL-like activity were secreted into the blood during mid-pregnancy. Serum from day-12 pregnant rats was subjected to high-performance liquid chromatography (HPLC) gel-filtration (TSK-G3000SswXL column), and PL activity was assayed by radioreceptor assay using 125I-labeled rat PRL and hepatocyte plasma membrane from pregnant rats. HPLC-gel filtration separated the PL activity into two peaks with mol wt of 55-60 K and 45-50 K, as estimated by reference to the elution volume of standard proteins. We tentatively designated these peaks PL-α and PL-β, respectively. Considering these mol wt, PL-β seemed to be identical to PL-I. mRNA was extracted from samples of placenta obtained each day from day 8 to day 12 of pregnancy and analyzed by means of a translation system involving micro-injection into Xenopus oocytes. The time of appearance of the mRNAs corresponding to PL-α and PL-β did not correspond and differed according to the day of pregnancy, suggesting that there are individual mRNAs for each PL in rat placenta. Treatment of PL-α and PL-β with peptide: N-glycosidase F completely abolished the binding activity to their receptors. Also since they were sensitive to glycosidases such as endoglycosidase H, endoglycosidase F and neuraminidase, these PLs were considered to possess N-linked glycoresidue(s) and to be sialylated. Based on the results, there are two distinct PLs, which are secreted at mid-pregnancy, are glycosylated and have different mRNAs.
AB - Two forms of placental lactogen (PL), designated PL-I and PL-II, have been reported in the serum of pregnant rats PL-I was secreted during mid-pregnancy and PL-II was secreted near term. In the present study, we found that two distinct forms with PL-like activity were secreted into the blood during mid-pregnancy. Serum from day-12 pregnant rats was subjected to high-performance liquid chromatography (HPLC) gel-filtration (TSK-G3000SswXL column), and PL activity was assayed by radioreceptor assay using 125I-labeled rat PRL and hepatocyte plasma membrane from pregnant rats. HPLC-gel filtration separated the PL activity into two peaks with mol wt of 55-60 K and 45-50 K, as estimated by reference to the elution volume of standard proteins. We tentatively designated these peaks PL-α and PL-β, respectively. Considering these mol wt, PL-β seemed to be identical to PL-I. mRNA was extracted from samples of placenta obtained each day from day 8 to day 12 of pregnancy and analyzed by means of a translation system involving micro-injection into Xenopus oocytes. The time of appearance of the mRNAs corresponding to PL-α and PL-β did not correspond and differed according to the day of pregnancy, suggesting that there are individual mRNAs for each PL in rat placenta. Treatment of PL-α and PL-β with peptide: N-glycosidase F completely abolished the binding activity to their receptors. Also since they were sensitive to glycosidases such as endoglycosidase H, endoglycosidase F and neuraminidase, these PLs were considered to possess N-linked glycoresidue(s) and to be sialylated. Based on the results, there are two distinct PLs, which are secreted at mid-pregnancy, are glycosylated and have different mRNAs.
KW - glycoprotein
KW - placenta
KW - placental lactogen-α
KW - placental lactogen-β
KW - pregnancy
UR - http://www.scopus.com/inward/record.url?scp=0026391091&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0026391091&partnerID=8YFLogxK
M3 - Article
VL - 38
SP - 533
EP - 540
JO - Endocrine Journal
JF - Endocrine Journal
SN - 0918-8959
IS - 5
ER -