Effect of Phospholipases and Lysophosphatides on Partially Purified Steroid Hormone Receptors

Westphal, Hannes M.; Fleischmann, Gerhard; Climent, F.; Beato, Miguel

doi:10.1515/bchm2.1978.359.2.1297

Cited by 27 publications

(7 citation statements)

References 5 publications

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“…The detergent action of lysophosphatides (formed by phospholipase action) on progesterone receptor-like pro teins [2] can have more physiological significance than an increase of the arachidonic acid cascade, because the uterine smooth muscle is more sensitive to the decrease of progesterone action than to the increase of arachi donic acid cascade products [16]. In pathological condi tions like chorionamnionitis, the role of phospholipases can be dramatic [4], UCB had twice as much PLA2 on average as maternal blood.…”

Section: Discussionmentioning

confidence: 99%

“…The deter gent lysophosphatide formed in this enzymatic reaction inactivates progesterone receptors [2] and causes the experimental respiratory distress syndrome [3], PLA2 activity in the amniotic membranes is in creased by bacteria and causes premature rupture of membranes followed by clinical labor [4], The activity increases progressively in the fetal pancreas with gesta tional age, being high in the mature gland [5], and is related to various diseases when the proenzyme is acti vated by tryptic cleavage of the N-terminal heptapeptide [3], The activity can be regulated by factors like ste roid sulfates [but not free steroids, see 6] and phospholi pase inhibitory proteins from human amniotic fluid (AF) [7], PLA2 release is influenced by estradiol and progesterone [8].…”

Section: Introductionmentioning

confidence: 99%

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Pancreatic and Catalytic Phospholipase A<sub>2</sub> in Relation to Pregnancy, Labor and Fetal Outcome

Pulkkinen

Eskola²,

Kleimola³

et al. 1990

Gynecol Obstet Invest

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The serum pancreatic and catalytic phospholipase A₂ level (PLA₂) in human pregnancy is normal, and the increase of pancreatic enzyme before delivery is small. In patients with pruritus associated with obstetric hepatosis maternal serum had a slightly lower pancreatic PLA2 level if the cholic acid level was higher. Umbilical cord blood has twice as much pancreatic PLA2 as maternal blood. If the enzyme concentration was very high, pregnancies were postterm and the newborns had low Apgar scores. Amniotic fluid contains these enzymes, but there is no change in the enzymes during the course of pregnancy. The amount of pancreatic enzyme was not reflected in catalytic activity. A very high PLA2 activity was observed in 1 patient with suspected amniotic fluid embolism and in the meconium, but low in the first urine of neonates.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Pancreatic and Catalytic Phospholipase A<sub>2</sub> in Relation to Pregnancy, Labor and Fetal Outcome

Pulkkinen

Eskola²,

Kleimola³

et al. 1990

Gynecol Obstet Invest

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“…The binding of effectors and inhibitors and of catalytic properties of enzymes were shown to be affected by phospholipid cleavage [1,2,4,5,10,11,13,28,36,37,43,48].…”

Section: Discussionmentioning

confidence: 99%

“…Insight into the underlying processes was provided by the removal of split products by serum albumin [10,11,13,37,43] and their insertion into normal membranes [1,2,10,28,29,32,41,46,48,51). By these strategies it could be shown that in some instances the effects of phospholipase A2 are caused by cleavage products and not by the disappearance of the native phospholipid [1,10,28].…”

Section: Discussionmentioning

confidence: 99%

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Influence of enzymatic phospholipid cleavage on the permeability of the erythrocyte membrane: III. Discrimination between the causal rôle of split products and of lecithin removal

et al. 1981

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Cleavage of 55% of the lecithin in intact human erythrocytes by phospholipase A2 (bee venom) markedly inhibits the mediated transport of L-lactate (via the monocarboxylate carrier) and of L-arabinose (via the monosaccharide carrier), while the major anion exchange system (probed by oxalate) and diffusion via the lipid domain (probed by erythritol) remain essentially unaltered. the causal role of the split products, unsaturated fatty acids and saturated lysolecithin, and of lecithin removal were now studied by sequential extraction of split products with serum albumin and by their controlled insertion into normal membranes. Careful choice of the albumin-to-cell ration allowed the extraction of more than 95% or the fatty acids and up to 80% of the lysolecithin without hemolysis. Extraction of fatty acids abolished inhibition of lactate and arabinose transfer, but induced inhibition of anion exchange and translipid permeation. Subsequent extraction of lysolecithin produced no further effects except on lactate transfer, which was inhibited. Exogenous oleic and linoleic acid, at intramembrane concentrations equal to those produced by phospholipase A2, inhibit lactate and arabinose transfer, while accelerating oxalate and erythritol movements, in agreement with effects of endogenous fatty acids. Exogenous lysolecithin inhibits all mediated transfer processes but does not alter translipid permeation. This pattern differs from that obtained for endogenous lysolecithin. The action of exogenous lysolecithin can be suppressed by loading of the cells with cholesterol. Insertion of exogenous lysolecithin into cells depleted of endogenous lysolecithin does not restore the functional state before depletion, indicating that exogenous and endogenous lysolecithin may act differently.

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The preparative refinement of steroid specific antibodies by affinity chromatography combined with electrophoretic desorption. Apparatus and method

Müller

Palluk

Kempfle

1984

J. Chem. Technol. Biotechnol.

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The preparative refinement of antibodies to testosterone and 5α‐dihydrotestosterone was achieved by prepurification (filtration, fractionation with ammoniumsulphate), followed by affinity chromatography of the antiserum. The affinity sorbent was synthesised by coupling 5α‐dihydrotestosterone with Sepharose CL 6B. After elution of the interfering admixture, there was desorption by the use of an electric field, using a specially developed apparatus. This apparatus and the method employed provided preparative amounts of antibodies, without significant impairment of affinity. The interfering self fluorescence of the serum was greatly diminished by this refinement procedure. The refined antibodies obtained were suitable for use with sensitive fluorometric testings (i.e. homogeneous fluoroimmunoassay).

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Effect of Phospholipases and Lysophosphatides on Partially Purified Steroid Hormone Receptors

Cited by 27 publications

References 5 publications

Pancreatic and Catalytic Phospholipase A<sub>2</sub> in Relation to Pregnancy, Labor and Fetal Outcome

Pancreatic and Catalytic Phospholipase A<sub>2</sub> in Relation to Pregnancy, Labor and Fetal Outcome

Influence of enzymatic phospholipid cleavage on the permeability of the erythrocyte membrane: III. Discrimination between the causal rôle of split products and of lecithin removal

The preparative refinement of steroid specific antibodies by affinity chromatography combined with electrophoretic desorption. Apparatus and method

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