Placental and Plasma Cystine Aminopeptidase in Pregnant Animals.

Ikenaga, Hidenori; Mizuta, Yohichi; Ono, Kenichiro; T, Sawazaki; Suzuki, Naoyoshi; Tomoda, Isamu

doi:10.1292/jvms.55.479

Cited by 5 publications

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“…On the other hand, Hrabak et al [6] demonstrated that plasma CAP activities in pregnant guinea pigs showed remarkably high and decreased with length of gestation, whereas increased significantly in women. In pregnant horses , plasma CAP showed same inhibitory effects by ethylene diamine tetra-acetic acid (EDTA), L-methionine, and heat treatment as those of placental CAP [7] like as those in women [8, 10 , 11]. However, no changes was observed during pregnancy in this study.…”

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confidence: 52%

“…Plasma CAP activities in pregnant women increased remarkably at the late gestational period and these values were found to be available for estimating maternal gestational condi tions [4,13]. Since plasma CAP showed identical inhibitory effects by certain con ditions to those of placental CAP in preg nant horses [7] (Sankyo Co., Ltd.) using S-benzyl-L--cystine-p-dimethylaminoanilide as a sub strate. Fig.…”

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Changes of Plasma Cystine Aminopeptidase Activities in Pregnant Horses

Ikenaga

Shimada

Ono

et al. 1993

JJES

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Plasma Cystine aminopeptidase (CAP) activities were examined in 40 pregnant and 10 nonpregnant Thoroughbred horses by spectrophotometric analysis using S-benzyl-L-Cystine-p dimethylaminoanilide as a substrate. Plasma CAP activities were remarkably low and no difference was observed between pregnant and non-pregnant horses. No changes of plasma CAP activities related with pregnant conditions, such as placental growth, functions and fetal growth, were observed. These results suggested that the plasma CAP activities seemed to be unavailable for the marker of maternal gestational conditions in horses.

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confidence: 52%

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Changes of Plasma Cystine Aminopeptidase Activities in Pregnant Horses

Ikenaga

Shimada

Ono

et al. 1993

JJES

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“…CAP was extracted from the fetal and maternal placentas, uteri and liver according to the method of Ikenaga et al (1993). These tissues were minced in small pieces and homogenized with Teflonglass homogenizers in 5 vol of 5 mM Tris-HCl buffer, pH 7.4, containing 0.25 M sucrose.…”

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confidence: 99%

Changes in Cystine Aminopeptidase (Oxytocinase) Activity in Mouse Serum, Placenta, Uterus and Liver during Pregnancy or after Steroid Hormone Treatments

Matsumoto

Mori

1998

Zoological Science

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Changes in cystine aminopeptidase (CAP) activity in serum, placenta, uterus and liver in mice under various physiological conditions were examined by enzymatic analysis using S-benzyl-L-cysteine-4-methylcoumaryl-7-amide as a substrate. Changes in serum CAP activity during pregnancy were less remarkable than those reported in humans; the activity was highest at day 13 of pregnancy and lowest at day 17. During the estrous cycle, the serum CAP level was high at diestrus, as high as that at day 13 of pregnancy. The activity in the male serum was significantly low compared to that in the diestrous serum. Although the CAP level was especially high in the maternal placenta, levels were also high in the fetal placenta, uterus and liver as compared with the serum, suggesting CAP synthesis in these tissues. The CAP activity in the uterine tissue was lower in pregnant than normal cycling mice. Furthermore, the serum CAP activity was modulated by estrogen and progesterone both in females and males, and by androgen in males. The relevance of these findings to the physiological role of CAP was discussed.

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“…Several investigators have measured relatively high levels of oxytovities were decreased by 90% cinase in the maternal circulation during human pregnancy were completely inactivated [9,17]. This causes a significant increase in the metabolic n. Inhibition of cystine amiclearance rate for OT during gestation [18], but there apheat treatment has been depears to be no significant change in serum oxytocinase aceared to be a characteristic of tivity that could result in increased OT availability at the in several other species [14]. onset of labor [17].…”

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confidence: 99%

Metabolism of Oxytocin in Rat Uterus and Placenta in Late Gestation1

Mitchell

Fang

Wong

1997

Biology of Reproduction

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Concentrations of oxytocin (OT) peptide increase in rat uterine tissues at the time of parturition. We have measured the rate of OT metabolism in these tissues in late gestation to determine whether a decrease in OT catabolism is responsible for the increase in OT concentrations. Uterine and placental tissues were obtained from groups of rats at Days 16, 19, 21, 21.5, 22, and after delivery of the first pup. Delivery usually occurs in the early afternoon of Day 22. Some animals were treated with the estrogen receptor blocker tamoxifen, which will delay parturition by approximately 24 h. Cytosolic and microsomal preparations obtained using ultracentrifugation were incubated with radiolabeled OT. Metabolites were separated using HPLC, and enzyme kinetic parameters were calculated. OT was actively metabolized in both uterine and placental tissues. Total oxytocinase activity was similar in the two tissues. In uterine tissues, activity was greater in the cytosolic fractions. In placenta, activity was evenly distributed between the cytosolic and microsomal fractions. The cytosolic fractions of each tissue contained predominantly post-proline endopeptidase activity, whereas the microsomes contained predominantly aminopeptidase activity. There was a slight trend to decreasing oxytocinase activity with advancing gestation in both subcellular fractions, but this was statistically significant only in the microsomal fraction. The maximal decline in activity was only 25-50%. Tamoxifen treatment had no effect on oxytocinase activity. We conclude that rat uterine and placental tissues contain post-proline endopeptidase and aminopeptidase activities that metabolize OT. It is doubtful that changes in these activities are major factors in regulating the increase in OT concentrations measured in rat intrauterine tissues at the time of parturition.

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Placental and Plasma Cystine Aminopeptidase in Pregnant Animals.

Cited by 5 publications

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Changes of Plasma Cystine Aminopeptidase Activities in Pregnant Horses

Changes of Plasma Cystine Aminopeptidase Activities in Pregnant Horses

Changes in Cystine Aminopeptidase (Oxytocinase) Activity in Mouse Serum, Placenta, Uterus and Liver during Pregnancy or after Steroid Hormone Treatments

Metabolism of Oxytocin in Rat Uterus and Placenta in Late Gestation1

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