Eeva-Marja Rutanen

Distribution of placental protein 14 in tissues and body fluids during pregnancy

Summary. Placental protein 14 (PP14) levels were measured in serum samples from non‐pregnant and pregnant women. amniotic fluid, cord blood, and extracts of placenta, decidua and fetal membranes. The levels were low (15–40 μg/l) in serum of non‐pregnant women. In four pregnancies following in‐vitro fertilization, the serum PP14 levels started to rise 2–12 days after embryo replacement. In normal pregnancy, the highest serum PP14 concentrations (up to 2200 μg/l) were detected between 6 and 12 weeks. After 16 weeks the level decreased and plateaued at 24 weeks to around 200 μg/l. In amniotic fluid, the highest PP14 levels (232 mg/l) were found between 12 and 20 weeks, being considerably higher than those in maternal serum throughout pregnancy. In cord blood, the levels were low (15–22 μg/l) or undetectable. In early pregnancy decidua. the PP14 content was higher (41–160 mg/g total protein) than in late pregnancy decidua (60–2700 μg/g total protein). In amnion and chorion laeve, the PP14 concentration varied from 50 to 750 and 50 to 1000 μg/g protein, respectively. Early pregnancy placenta contained 0‐25‐15 mg/g and late pregnancy placenta 3–430 μg/g protein of PP14. These results show that the levels of PP14 in pregnancy serum have a similar profile to hCG, but in contrast to other placental proteins, the amniotic fluid PP14 levels are remarkably high. This may be explained by suggesting that decidua is a source of PP14.

Radioimmunoassay of placental protein 12: Levels in amniotic fluid, cord blood, and serum of healthy adults, pregnant women, and patients with trophoblastic disease

A radioimmunoassay for placental protein 12 (PP12) is described and the levels in amniotic fluid, cord blood, and serum of nonpregnant individuals, pregnant women, and patients with trophoblastic disease are presented. During pregnancy, the highest PP12 levels were found at 22 to 23 weeks (mean +/- SD, 169 +/- 123 ng/ml), and there was a transient decline at 32 to 33 weeks (63 +/- 23 ng/ml). In amniotic fluid, the levels were 100 to 1,000 times higher than in maternal serum. In cord blood at birth, the values were of the same magnitude as in maternal serum. Also healthy nonpregnant women and men had PP12-like immunoreactivity in serum. Nonpregnant women (9 to 47 ng/ml) had higher levels than men (undetectable to 21 ng/ml). Elevated levels up to 84 ng/ml were occasionally observed in trophoblastic disease, both hydatidiform mole and choriocarcinoma, but they bore no correlation with the human chorionic gonadotropin levels. On the basis of these results PP12 is not a suitable marker for trophoblastic disease. PP12 values in normal pregnancy provide the basis for the evaluation of PP12 levels in abnormal pregnancy.

Placental protein 12 (12) in the human endometrium: tissue concentration in relation to histology and serum levels of 12, progesterone and oestradiol

Placental protein 12 (12) was measured by radio‐immunoassay in serum and endometrial extracts of 25 women at various phases of the menstrual cycle, and in the decidua from six women undergoing legal abortion in early pregnancy. The results were analysed with respect to endometrial histology and serum oestradiol, progesterone and 12 concentrations. 12 was detected in the secretory phase endometrium and decidua, but not in the proliferative phase endometrium. The 12 concentration in tissue increased from early (1.3–9.4 μg/g protein) to late secretory phase (5.3‐155 μg/g), and considerably higher levels were found in decidua (282‐3846 μg/g). There was a correlation (P<0.001) between endometrial 12 and serum progesterone levels in non‐pregnant women, and there also was a slight correlation (P<0.05) between endometrial and serum 12 concentrations. These results show that 12 is not pregnancy specific and suggest that the occurrence of 12 is dependent on progesterone.

Pregnancy proteins in seminal plasma, seminal vesicles, preovulatory follicular fluid, and ovary.

A number of proteins previously thought to be specific for the placenta or pregnancy have been identified in the fluids bathing both the oocyte and the sperm. In many cases their concentrations in follicular fluid and seminal plasma greatly exceeded those in the serum of nonpregnant women or men, and sometimes they even exceeded the levels in pregnancy sera. We report here the occurrence of PP5, PP12, PP14 and PAPP-A in follicular fluid and seminal plasma. In follicular fluid, the levels of PP5, PP12, and PAPP-A correlate with the estrogen concentration of the same fluid, and the PP12 and PAPP-A levels also bear a positive correlation to the progesterone concentration. The levels of PP12 and PAPP-A increase as the follicle grows, as do the levels of many steroid hormones. Therefore, the apparent correlations observed may be merely coincidental. However, circumstantial evidence from other reproductive organs indicates that the synthesis of PP12 and PAPP-A is stimulated by progesterone. Results of immunohistochemical staining show that PP12 and PAPP-A are localized in the luteinized granulosa cells and the corpus luteum. Previous studies indicate that PP5 and PAPP-A inhibit the action of proteolytic enzymes plasmin and elastase, which are believed to be involved in the mechanisms of ovulation. The study of the significance of these various placental proteins for human reproduction is only at its beginning. Clearly, elucidation of their function is the key to a more fundamental understanding of their role in the events governing ovulation and implantation.

Placental protein 12 (PP12): Factors affecting levels in late pregnancy

The circulating concentration of placental protein 12 was measured by radioimmunoassay in 109 pregnant women. The effect on the serum PP12 level of temperature, repeat freezing and thawing, and day-to-day and diurnal variation were assessed and the post partum changes of levels were studied. On average, PP12 levels in plasma are about one-half of those in serum in the same individual. PP12 immunoreactivity is destroyed by heating but not by repeated freezing and thawing. Changes in serum PP12 levels at various times of day showed a significant and consistent diurnal variation (F = 7.21; d.f.24; 96; P less than 0.001). The peak mean (+/- s.e.m.) value at 0800 h (80.8 +/- 8.7 ng/ml) was 41 per cent higher than the 24-h mean (P less than 0.05), and the nadir concentration at 1400 h (40.4 +/- 5.4 ng/ml) was 29 per cent lower than the 24-h mean (P less than 0.025). There is also considerable day-to-day variation (up to 72 per cent) in serum PP12 levels. If serum samples are taken at 0700 h, there is a slight negative correlation between PP12 concentration and placental weight (P less than 0.05), but not between PP12 level and birthweight of the child. In term pregnancy, the levels taken at 0700 h are higher (163.7 +/- 12.4 ng/ml) than at 0900 to 1300 h (115.7 +/- 11.4 ng/ml, P less than 0.001). The PP12 level is not affected by labour.(ABSTRACT TRUNCATED AT 250 WORDS)

Seminal Plasma Levels of PAPP-A in Normospermic and Oligospermic Men and Tissue Localization of PAPP-A in the Male Genital Tract

Radioimmunoassay, gel filtration, isoelectric focusing, and immunoperoxidase methods were used to study the levels, properties, and localization of pregnancy-associated plasma protein A (PAPP-A) in the human seminal plasma and male genital tract. Seminal plasma specimens from 20 normospermic and 20 oligospermic men were studied. PAPP-A was found in 30 of 40 samples, the levels ranging from undetectable to 135 micrograms/liter (median 35 micrograms/liter) in the normospermic group and from undetectable to 111 micrograms/liter (median 21 micrograms/liter) in the oligospermic group. There was no significant difference in the PAPP-A levels between the two groups, and no correlation was observed between the seminal plasma PAPP-A levels and the volume of seminal plasma or the sperm count or the viability of spermatozoa. Serial dilutions of seminal plasma and PAPP-A standard yielded parallel dose-response curves, and incubation with seminal plasma did not result in any change in the elution pattern of [125I]PAPP-A in gel filtration. PAPP-A-immunoreactive material from seminal plasma eluted as two peaks, the major one corresponding to the elution volume of purified PAPP-A and the minor eluting more slowly. The isoelectric point of seminal plasma PAPP-A was 4.3-4.7 and that of term pregnancy serum was 4.2-4.6. In the immunoperoxidase staining, PAPP-A was seen in the epithelium of the prostate, seminal vesicle, and the ampullar part of the vas deferens but not in the testis, epididymis, proximal parts of vas deferens or urethra. The results confirm the occurrence of PAPP-A in the seminal plasma but do not suggest any clinical utility for seminal plasma PAPP-A measurements.(ABSTRACT TRUNCATED AT 250 WORDS)

Elevated levels of a somatomedin-binding protein PP12 in patients with ovarian cancer

The circulating levels of placental protein 12 (PP12), a somatomedin‐binding protein, were measured by radioimmunoassay in 37 postmenopausal women with ovarian tumors. Elevated levels (above 47 μg/1) were observed in 16 of 25 patients (64%) with malignant and 2 of 12 patients (17%) with benign tumors. Elevated levels were more frequent and higher in patients with advanced disease. Within 1 week of surgery, the levels fell in 13 of 17 cases (77%). In addition to clinical interest, these results contribute to our knowledge of carrier proteins of growth factors in patients bearing malignant ovarian neoplasms.

Placental protein 10 (PP10) in normal pregnancy and cholestasis of pregnancy

Summary. The circulating concentrations of placental protein 10 (PP10) were measured by radioimmunoassay in 288 women with normal pregnancy and ten women (55 samples) with cholestasis of pregnancy. Serum PP10 levels were not affected by changes in incubation and storage temperature, and no diurnal variation was observed. The highest PP10 levels (36–85 μg/1) in normal pregnancy were found at 34 weeks. The postpartum decline of serum PP10 concentration corresponded to an average half‐life of 18h. In cholestasis of pregnancy at 32–39 weeks, the serum PP10 levels were found to be lower than normal. Negative correlation was observed between aminotransferase and PP10 levels in serum and between the bile acid levels and the PP10 concentration. These results suggest that the severity of maternal liver disorder is reflected in the circulating PP10 concentration.

The content of placental protein 12 in decidua and fetal membranes is greater than in placenta.

Summary. Radioimmunoassay, gel filtration and sodium dodecyl sulphate‐polyacrylamide gel electrophoresis were used to study the content and properties of placental protein 12 (PP12) in the placenta, decidua and fetal membranes. The tissues were obtained from early pregnancy in 12 cases, and after normal term delivery in eight cases in seven of which chorion and amnion laeve were also studied. There was more PP12 in decidua and fetal membranes than in placenta. The decidua/placenta ratio of PP12 content ranged from 2 to 1154 (mean 193, SEM 66). These results suggest that PP12 is a decidual rather than placental protein.

Placental protein 12 (PP12) in menstrual fluid

Summary. In a previous study we found placental protein 12 (PP12) in the human endometrium. We now show that PP12–like immunoreactive material is released into menstrual fluid where it occurs at concentrations from 43 to 32000 μg/l. The PP12 levels in menstrual fluid are 2– to 2000–fold higher than in serum of the same individuals thus suggesting that the protein either concentrates or is produced in the endometrium. The addition of protease inhibitors has no effect on the PP12 levels. In radioimmunoassay, the dose‐response curves of menstrual fluid PP12 and placental PP12 are parallel. Experiments with fused rocket immunoelectrophoresis show that menstrual and placental PP12 are indistinguishable from each other. In gel filtration, menstrual PP12 has the same molecular weight as that of purified placental PP12. By immunoperoxidase staining, PP12 is localized in the glandular epithelial cells of the menstrual endometrium. The glandular localization and high concentration of PP12 in menstrual fluid, as compared with PP12 levels in serum and endometrium, suggest that PP12 may be secreted by the endometrium.