Two distinct placental lactogen-like substances in serum during mid-pregnancy in the rat

N. Furuyama, K. Shiota, M. Takahashi

Research output: Contribution to journalArticle

14 Citations (Scopus)

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 languageEnglish
Pages (from-to)533-540
Number of pages8
JournalEndocrinologia Japonica
Volume38
Issue number5
Publication statusPublished - 1991
Externally publishedYes

Fingerprint

Placental Lactogen
Pregnancy
Serum
Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase
Messenger RNA
Glycoside Hydrolases
Placenta
Gel Chromatography
High Pressure Liquid Chromatography
Radioligand Assay
Neuraminidase
Xenopus
Oocytes
Hepatocytes

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 journalArticle

Furuyama, N, Shiota, K & Takahashi, M 1991, 'Two distinct placental lactogen-like substances in serum during mid-pregnancy in the rat', Endocrinologia Japonica, vol. 38, no. 5, pp. 533-540.
Furuyama, N. ; Shiota, K. ; Takahashi, M. / Two distinct placental lactogen-like substances in serum during mid-pregnancy in the rat. In: Endocrinologia Japonica. 1991 ; Vol. 38, No. 5. pp. 533-540.
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