The presence of phosphodiesterase IV has been demonstrated in the human fetal brain, liver and placenta as early as in the 6th week of intrauterine development. The enzyme activity in each tissue increases with gestation, being maximum at 18-21 wk and then decreases. The Km values of this enzyme for bis-(p-nitrophenyl)-phosphate hydrolysis in the brain, liver and placenta are 2.94 mM, 1.47 mM and 1.66 mM, respectively. Presence of sulfhydryl group in the active center of the placental enzyme has been demonstrated with the help of cationic study. EDTA inhibits the enzyme in all the three tissues. Effect of concanavalin A reveals the absence or unexposition of glucose, mannose and N-acetylglucosamine moieties in the active site of the enzyme in each of the three tissues. Maximum enzyme activity has been found to be localized in the soluble supernatant fraction obtained on centrifuging the brain and liver homogenate at 105,000 × g and in 20,000 × g pellet of the placenta. © 1982.

D CHAUDHURI

J KUSHARI

M MUKHERJEA

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Occurrence of phosphodiesterase IV in the developing human brain, liver and placenta.

European Journal of Obstetrics and Gynecology and Reproductive Biology

Reactive oxygen species (ROS) pose a serious threat to maternal and fetal health during pregnancy. However, there is little information on the oxidative damage caused by ROS and its protection during prenatal life. The present study highlights the status of various antioxidants in human placental and fetal tissues at different phases of gestation. The activity profile of scavenging enzymes, superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase as well as the concentrations of non-enzymatic antioxidants, ascorbic acid, α-tocopherol, bilirubin and glutathione have been determined in human placental whole homogenate, placental brush border membrane and fetal liver over gestational periods ranging from 6 weeks of pregnancy till birth. The ontogenic profile of lipid peroxidation, a marker of oxidative damage has also been investigated in the feto-placental system. Catalase, superoxide dismutase and glutathione reductase activities increased significantly, but glutathione peroxidase activity remained almost the same throughout development. Except α-tocopherol and bilirubin, the concentrations of other non-enzymic scavengers followed a significant increasing trend with advancement of pregnancy. Results indicate that there is gradual suppression of lipoperoxide formation with the progress of gestation to protect the fetus against oxygen toxicity. © 2000 Kluwer Academic Publishers.

Molecular and Cellular Biochemistry

Ontogenic profile of some antioxidants and lipid peroxidation in human placental and fetal tissues

The human feto-placental unit being in the environment of the materno-fetal circulation is very much susceptible to the danger of reactive oxygen species-induced oxidative damage. The present study reports the status of various antioxidants in the feto-placental system at birth. The activities of superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase as well as concentrations of non-enzymic antioxidants viz, ascorbic acid, α-tocopherol, bilirubin and glutathione have been determined in term placental brush border membrane (BBM) and umbilical cord (UC) blood. The extent of lipid peroxidation in developing and term BBM and UC blood has been studied by estimation of malondialdehyde and conjugated dienes, both being the end products of lipid peroxidation. The results indicate the presence of a protective mechanism against oxygen toxicity in the feto-placental system at the time of parturition. Copyright (C) 1999.

Clinica Chimica Acta

Antioxidant status and lipid peroxidation in human feto-placental unit

Human placental syncytiotrophoblast basal membrane plays an important role in transfer of nutrients from the mother to the growing fetus all throughout gestation. The membrane lipid composition together with the bilayer fluidity is found to be the major index in modulation of these transport processes. In the present study, the effects of changing lipid composition on the placental basal membrane fluidity and the modulating influence of the latter on membrane enzyme and transport functions with progress of gestation, were investigated. Steady-state fluorescence analysis using 1,6-diphenyl-1,3:5 hexatriene as the probe, indicated a decrease in fluorescence anisotropy of both labeled native membrane vesicles and liposomes prepared from lipids extracted from the basal membrane vesicles, signifying increased bilayer fluidity with progress of gestation. This in turn, was successfully correlated to the lowering of cholesterol content and enhanced phospholipid concentration with a steady decrease in cholesterol/phospholipid ratio during placental development. Enhanced Na+-K+-ATPase activity and steady-state glucose uptake across basal membrane with gestational progress suggested modulation of membrane protein functions by the fluidity, which was further corroborated by the increased bilayer fluidity and enzyme activity in benzyl alcohol treated basal membrane in each gestational age group.

Changes in lipid composition and fluidity of human placental basal membrane and modulation of bilayer protein functions with progress of gestation

The syncytiotrophoblastic brush-border membrane (BBM) of human placenta plays a vital role in the exchange of metabolites between mother and developing fetus. The fluidity of this membrane renders its selective permeable character. To meet the changing needs of the growing fetus with the progress of gestational age changes in the composition and properties of BBM occur. In the present study, decrease in cholesterol/phospholipid ratio of BBM indicated an increase in fluidity with advancement of gestational age. Measurement of the steady state fluorescence anisotropy of labeled liposomes prepared from lipid extract of BBM as well as that of labeled BBM vesicles prepared from native BBM shows decrease in restriction of the bound dye molecule with increased gestational age. Decrease in transition temperature of BBM and enhanced glucose transport through it have been observed with advancement of pregnancy. © 1995.

BBA - Biomembranes

Increase in fluidity of human placental syncytiotrophoblastic brush-border membrane with advancement of gestational age: A fluorescence polarization study

The activities of the enzymes glycerol-3-phosphate dehydrogenase and fatty acid synthase are inhibited by palmitoyl-coenzyme A and oleate. The two isoforms of fatty acid binding proteins (PI 6.9 and PI 5.4) enhance the activities of glycerol-3-phosphate dehydrogenase and fatty acid synthase in the absence of palmitoyl-coenzyme A or oleate and also protect them against palmitoyl-coenzyme A or oleate inhibition. Levels of fatty acid binding proteins, the activities of the enzymes fatty acid synthase and glycerol-3-phosphate dehydrogenase increase with gestation showing a peak at term. However, the activity of fatty acid synthase showed the same trend up to the 30th week of gestation and then declined slightly at term. With the advancement of pregnancy when more lipids are required for the developing placenta, fatty acid binding proteins supply more fatty acids and glycerol-3-phosphate for the synthesis of lipids. Thus a correlation exists between glycerol-3-phosphate dehydrogenase, fatty acid synthase and fatty acid binding proteins in developing human placenta. © 1995 Indian Academy of Sciences.

Journal of Biosciences

Relationship between glycerol-3-phosphate dehydrogenase, fatty acid synthase and fatty acid binding proteins in developing human placenta

Mitochondrial lipids and ATPasc activity have been studied in developing human placenta. The enzyme activity in the placenta increases steadily with gestational age until the 18th to 21st week, and decreases in the second half of pregnancy. Both Mg2+ and Ca2+ ions have been found to activate the enzyme system. The solubilization of membrane lipids by deoxycholate inhibits the enzyme activity. Total lipid and total phospholipid contents of the mitochondrial membranes also increase during the early development of the placenta with peaks in the 14th to 17th week, after which the levels decrease. Howevcr, the percentage composition of individual phospholipids remains almost the same throughout pregnancy. The profile of the ATPase activity exhibits a correlation with that of membrane lipids in human placenta during intrauterine development of the tissue. © 1980 S. Karger AG, Basel.

Journal	European Journal of Obstetrics and Gynecology and Reproductive Biology
Publisher	-
ISSN	0028-2243