CIRCULATING LEVELS OF PREGNANCY‐SPECIFIC β<sub>1</sub>‐GLYCOPROTEIN IN EARLY PREGNANCY

Grudzinskas, J. G.; Lenton, Elizabeth A.; Gordon, Y. B.; Kelso, Ian; Jeffrey, Diana; Sobowale, O.; Chard, T.

doi:10.1111/j.1471-0528.1977.tb12483.x

Cited by 46 publications

(12 citation statements)

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“…Indeed, we reported that pulses of progesterone decrease both hCG levels and pulse frequency during superfusion (11), confirming a previously suggested paracrine inhibitory role of this steroid (18). SP1 is a placental glycoprotein the circulating levels of which increase during gestation (13) and so does its pulse frequency: from 14-15 min in the first trimester to 6-7 min at term (Fig. 3).…”

Section: Discussionsupporting

confidence: 77%

“…Other hor¬ mones like human placental lactogen (hPL) and pregnancy specific ßl glycoprotein (SP1) are circu¬ lating glycoproteins of placental origin which follow an opposite trend in circulation as compared with hCG. Their levels are low early and increase during gestation until close to term (2,13,14). In Also, in contrast to hCG and SP1, the secretion of hPL during superfusion at term is not episodic.…”

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confidence: 98%

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Patterns of spontaneous pulsatile secretion of human chorionic gonadotropin and pregnancy specific β1 glycoprotein by superfused placental explants in first and last trimester. Lack of episodic human placental lactogen secretion

Kaplan

Barnea²,

Bersinger³

1991

Acta Endocrinologica

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We have recently reported that during superfusion of placental explants, human chorionic gonadotropin secretion is episodic. In the present work we have examined, using the superfusion model, the pattern of secretion of other glycoprotein hormones, pregnancy specific \ g=b\ 1glycoprotein and human placental lactogen, in the first trimester and term placenta. This was done by evaluating the pulsatile pattern by two different computerized programmes. By using different sampling intervals (6-0.5 min) of the effluent, two distinct patterns of hCG secretion were detected in the first trimester: a short one, occurring every 8-9 min and the other every 18-25 min. In contrast, at term the only episodic pattern detected was every 40-50 min, with a low amplitude, 20-30% above baseline, and a declining baseline. In two out of seven placentas, no pulsatility was detected. The secretion of pregnancy specific \g=b\1glycoprotein was pulsatile, occuring every 14-15 min in the first trimester and every 6-7 min at term. Finally, the secretion of human placental lactogen at term was not pulsatile. The levels of this glycoprotein in the first trimester placenta were below detection limits. In conclusion, the patterns of the three glycopoproteins during superfusion are different, suggesting different paracrine/autocrine control mechanisms. The dynamic superfusion model also enables identification of thus far not reported gestational age-dependent differences in the secretion pattern of hCG and pregnancy specific \g=b\1glycoprotein.

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Section: Discussionsupporting

confidence: 77%

mentioning

confidence: 98%

Patterns of spontaneous pulsatile secretion of human chorionic gonadotropin and pregnancy specific β1 glycoprotein by superfused placental explants in first and last trimester. Lack of episodic human placental lactogen secretion

Kaplan

Barnea²,

Bersinger³

1991

Acta Endocrinologica

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“…In humans, PSG is produced by the syncytiotrophoblast starting as early as about the time of implantation [5]. Pregnancy-specific glycoprotein is released into the maternal circulation and increases in concentration as pregnancy proceeds, reaching a concentration of 200-400 g/ml at term [6].…”

Section: Introductionmentioning

confidence: 99%

Pregnancy-Specific Glycoprotein (PSG) in Baboon (Papio hamadryas): Family Size, Domain Structure, and Prediction of a Functional Region in Primate PSGs1

Zhou¹,

Hammarström²

2001

Biology of Reproduction

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Pregnancy-specific glycoprotein (PSG) constitutes a major component of serum of pregnant women and appears to be essential for a successful pregnancy. Its function is, however, still unknown. Because of the evolutionary divergence between human and rodent PSG, functional studies may require a primate animal model. We have characterized PSG transcripts in a baboon placenta cDNA library and analyzed baboon genomic DNA. The main PSG isoform had the domain structure N-A1-B2-C similar to the human type IIa isoform. The type I isoform (N-A1-A2-B2-C) was also expressed. Fifteen similar PSG genes were identified of which at least nine were simultaneously expressed in third trimester baboon placenta. Thus, the baboon PSG family was as complex as that of humans. Recombinant baboon PSG (isoform IIa) had a molecular weight of 38 kDa and reacted with antibodies against human PSG. Comparative analysis of 43 N-domain amino acid sequences of PSG from four species and nine primate carcinoembryonic antigen subgroup N domain sequences identified a number of residues in the GFCC'C" ss-sheet and FG loop that are probable candidates for PSG binding to its putative ligand.

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“…At approximately 36 weeks gestation peak concentrations of 200 to 300 mg/l have been measured (15). The development of a sensitive and specific radioimmunoassay (RIA) for this protein has permitted detection of SP, in the general circulation soon after conception (4,5 ) . However, little information is available on concentrations of SP, in early normal pregnancy.…”

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confidence: 99%

PREGNANCY SPECIFIC β₁ GLYCOPROTEIN AND CHORIONIC GONADOTROPHIN IN EARLY HUMAN PREGNANCY

Lenton

Grudzinskas

Gordon

et al. 1981

Acta Obstet Gynecol Scand

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Venous blood samples were collected prospectively in ten menstrual cycles where conception occurred, and for several weeks thereafter, and the circulating concentrations of pregnancy specific beta 1 glycoprotein (SP1) and human chorionic gonadotrophin (HCG) determined using specific radioimmunoassays. The data were converted to logarithms and pooled and pooled using the day of the LH peak as zero time. The concentration profiles so obtained were remarkable similar and showed a rapid exponential increase in concentration during the very early stage of pregnancy. The doubling times were 2.4 days and 2.3 days for SP1 and HCG respectively and both proteins were initially secreted in approximately equivalent concentrations. However, some 30 days following the LH peak, the concentration profiles began to diverge, with SP1 levels continuing to rise whilst HCG concentrations showed the characteristic plateau at 8 and 10 weeks of gestation.

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CIRCULATING LEVELS OF PREGNANCY‐SPECIFIC β₁‐GLYCOPROTEIN IN EARLY PREGNANCY

Abstract: Circulating levels of pregnancy-specific P,-glycoprotein (SP, or PSPG), luteinizing hormone (LH) and human chorionic gonadotrophin (HCG) were measured serially in 9 subjects immediately after conception. Ovulation occurred spontaneously

Cited by 46 publications

References 5 publications

Patterns of spontaneous pulsatile secretion of human chorionic gonadotropin and pregnancy specific β1 glycoprotein by superfused placental explants in first and last trimester. Lack of episodic human placental lactogen secretion

Patterns of spontaneous pulsatile secretion of human chorionic gonadotropin and pregnancy specific β1 glycoprotein by superfused placental explants in first and last trimester. Lack of episodic human placental lactogen secretion

Pregnancy-Specific Glycoprotein (PSG) in Baboon (Papio hamadryas): Family Size, Domain Structure, and Prediction of a Functional Region in Primate PSGs1

PREGNANCY SPECIFIC β₁ GLYCOPROTEIN AND CHORIONIC GONADOTROPHIN IN EARLY HUMAN PREGNANCY

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CIRCULATING LEVELS OF PREGNANCY‐SPECIFIC β1‐GLYCOPROTEIN IN EARLY PREGNANCY

Abstract: Circulating levels of pregnancy-specific P,-glycoprotein (SP, or PSPG), luteinizing hormone (LH) and human chorionic gonadotrophin (HCG) were measured serially in 9 subjects immediately after conception. Ovulation occurred spontaneously

Cited by 46 publications

References 5 publications

Patterns of spontaneous pulsatile secretion of human chorionic gonadotropin and pregnancy specific β1 glycoprotein by superfused placental explants in first and last trimester. Lack of episodic human placental lactogen secretion

Patterns of spontaneous pulsatile secretion of human chorionic gonadotropin and pregnancy specific β1 glycoprotein by superfused placental explants in first and last trimester. Lack of episodic human placental lactogen secretion

Pregnancy-Specific Glycoprotein (PSG) in Baboon (Papio hamadryas): Family Size, Domain Structure, and Prediction of a Functional Region in Primate PSGs1

PREGNANCY SPECIFIC β1 GLYCOPROTEIN AND CHORIONIC GONADOTROPHIN IN EARLY HUMAN PREGNANCY

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CIRCULATING LEVELS OF PREGNANCY‐SPECIFIC β₁‐GLYCOPROTEIN IN EARLY PREGNANCY

PREGNANCY SPECIFIC β₁ GLYCOPROTEIN AND CHORIONIC GONADOTROPHIN IN EARLY HUMAN PREGNANCY