PubMed Health⌕ Search

Biomedical subjects

M F Jayle

Publications and source records attributed to M F Jayle.

At least 37 records · Page 2Linked to original sources
PubMed1977

Rat iso-alpha1-fetoproteins. Purification and interaction with estradiol-17beta.

The combination of polyacrylamide gel electrophoresis and Concanavalin-A-Sepharose affinity chromatography has permitted the isolation on a preparative scale, of four molecular forms of rat alpha 1-fetoprotein: a "slow" and a "fast" fraction, each separable into Concanavalin-A-adsorbed ("high carbohydrate", i.e. rich in accessible alphaD-Mannosyl and alphaD-Glu-cosyl residues) and a Concanavalin-A-non adsorbed ("low carbohydrate") fractions. These four iso-alpha 1-fetoproteins (iso-AFP) bind estradiol-17beta. However, they disclose differences in both their association constants and number of binding sites for this hormone. Very high affinity sites (10(9) are mainly located on the "slow-low carbohydrate" form. Low affinity, high capacity sites are preferentially located on the "high carbohydrate" form. These results confirm the molecular and functional heterogeneity of rat AFT and suggest that the carbohydrate moiety of the protein may have a role in estrogen-AFP interactions.

Animals↗
PubMed1977

An enzyme-linked immunoassay of testosterone.

An enzyme-linked immunoassay of testosterone is described. The conjugation of testosterone with high specific activity horseradish per-oxidase and a highly sensitive assay for this enzyme having previously been studied, here we describe the immobilization of the anti-testosterone antibody and the development of assay conditions permitting the determination of 50 pg to 1.5 ng testosterone in one working day. In this work attention has been paid to keeping the assay method as simple as possible. The method is discussed in terms of other enzyme-linked immunoassays for steroids.

Cross Reactions↗
PubMed1977

Rat and human embryo and post-natal sera contain a potent endogenous competitor of estrogen-rat alpha-fetoprotein interactions.

A highly active inhibitor of the binding of estrone and estradiol-17beta to rat alpha-fetoprotein is demonstrated for the first time in embryo, immature and adult rat sera as well as in fetal and adult human sera. The competitive character and the narrow specificity of this inhibition effect is shown. The major compound responsible for this activity is isolated by successive column Sephadex LH20 and thin layer chromatography: it is characterized as a nonpolar, nonphenolic, dialysable and thermostable substance, unreactive towards anti-estrone and anti-estradiol-17beta antibodies. The possible biological role of an endogenous non-estrogen ligand of rodent fetoproteins is discussed.

Adrenalectomy↗
PubMed1977

[In vitro metabolism of (6,7-H3)estrone and of (6,7-H3) estradiol by the liver in pregnant guinea pigs].

Slices of pregnant guinea pig liver were incubated with (6,7-3H)estrone and with (6,7-3H)estradiol. Free, glucuro- and sulfo-conjugated fractions were isolated by specific extraction and hydrolysis. The radioactivity distribution in these 3 fractions demonstrated a predominance of conjugated compounds (95% of isolated estrogens) with slightly more glucuro-conjugated than sulfo-conjugated compounds. After isolating estrogens by TLC, we were able to determine estrone and estradiol in these 3 fractions from incubations with 3H-estrone or with 3H-estradiol by means of specific activity recrystallisation. Estriol was determined in glucuro-and sulfo-conjugated fractions after incubation with 3H-estrone as well as in sulfo-conjugated fraction after incubation with 3H-estradiol. Glucuro- or sulfo-conjugated estrone was the predominant estrogen after incubation with 3H-estrone just as after incubation with 3H-estradiol. This led us to conclude to an important 17beta-hydroxysteroid-dehydrogenase activity. The 16alpha-hydroxylastic-activity is weaker since estriol represented only 1,43 % of estrogens isolated after incubation with 3H-estrone and 0.82% after incubation with 3H-estradiol.

17-Hydroxysteroid Dehydrogenases↗
PubMed1977

[Experimental data on estradiol 3,17-diethers (author's transl)].

Estradiol ethers reveal a biological activity in female rats which decreases according to the length of the side chain at position 3. Further, percutaneous injections have an activity which is 6 to 30 times greater that subcutaneous ones. This suggests that de-etherification could occur, leading to estradiol. After percutaneous administration of tritiated promestriene (3-propyl ether, 17-methyl ether estradiol) and estradiol, a comparison of the uptake on the uterus and of uterotrophic effects as well as an analysis of radioactivity taken up indicates that a cleavage of both ether groups of promestriene occurs leading to estradiol. This de-etherification takes place in the liver, as demonstrated by perfused liver experiments. With promestriene, antagonist activity is shown on the seborrheic androgen-stimulated rat and on 5-alpha-reductase activity in vitro and in vivo.

Animals↗
PubMed1977

[Kinetics of transcutaneous penetration and fixation of 3-propoxy-17-methoxyestradiol and estradiol in various rat tissues].

The transcutaneous penetration of 3-propyl ether, 17-methyl ether oestradiol (POM) occurs by a diffusion phenomenon and does not seem to be modulated by a cutaneous receptor as it is the case for oestradiol. After transcutaneous administration of POM and oestradiol, a comparison of the kinetics of uptake on the uterus and of uterotrophic effects, as well as an analysis of radioactivity taken up by a partition method between petroleum ether and sodium hydroxide, indicates that cleavage of both ether groups of POM occurs leading to estradiol. It is likely that this de-etherification takes place in the liver after a period of quiescence. The lipophilic nature of POM allows an obvious uptake by the aorta and a very significant uptake by the adipose tissue. The etherification of the alcohol functions of oestradiol allows an adequate protection of the hormone against hepatic catabolism. This may explain, along with the release of metabolites taken up by the adipose tissue, that POM is bound to a greater extent than oestradiol by various tissues.

Animals↗
PubMed1976

[Determination, at equilibrium, of association constants of labelled or unlabelled ligands by a non-graphical method (author's transl)].

The present work deals with the determination of association constants at equilibrium by a non-graphical method in binding systems containing one specific receptor. Equations have have been derived from that originally described by Lea (Biochim. Biophys. Acta, 322, 68--74), the terms of which are obtained from the data of simple displacement curves of a bound radioactive ligand by unlabelled competitors identical or different in nature. By knowing the function relating the variations of the bound ligand (B) to the affinity constant (Ki) and the quantity (Mi) of competitor for a given system, it is possible to calculate any of these parameters when the two others are measured. Thus, it becomes easy to compare the relative affinities of differents receptors for the same ligand or that of one receptor for various labelled or unlabelled ligands. Furthermore, theoretical displacement curves can be drawn and compared to experimental data, when only knowing the affinity constant of a specific binding system in given conditions. These modes of calculation have been tested in a study of interactions between various steroids and a fraction of human serum proteins precipitated by ammonium sulfate (30-45%) and containing the sex hormone-binding globulin. Association constants thus obtained agree well with those reported in the literature and determined by graphical procedures.

Binding Sites↗
PubMed1976

[In vitro study of placental metabolism of (6,7-3H) estradiol -17 beta in guinea pigs].

The metabolism of (6-7-3H) estradiol-17 beta was studied in vitro in different cellular fractions of Guinea Pig placenta. The substrate was transformed into free as well as conjugated (hydrosoluble) estrone. It was thus possible to conclude, on one hand the existence of a very active microsomial 17 beta-hydroxy steroid-dehydrogenase and on the other the presence of a cytosolic system of estrogen conjugation. No estradiol-17 alpha or estriol were determined.

Animals↗
PubMed1976

Purification and interaction with estradiol-17beta.

The combination of polyacrylamide gel electrophoresis and Concanavalin-A-Sepharose affinity chromatography has permitted the isolation on a preparative scale, of four molecular forms of rat alpha1-fetoprotein: a "slow" and a "fast" fraction, each separable into Concanavalin-A-adorbed ("high carbohydrate", i.e. rich in accessible alphaD-Mannosyl and alphaD-Glucosyl residues) and a Concanavalin-A-non adsorbed ("low carbohydrate") fractions. These four iso-alpha-fetoproteins (iso-AFP) bind estradiol-17beta. However, they disclose differences in both their association constants and number of binding sites for this hormone. Very high affinity sites (10(9)) are mainly located on the "slow-low carbohydrate" form. Low affinity, high capacity sites are preferentially located on the "high carbohydrate" form. These results confirm the molecular and functional heterogeneity of rat AFP and suggest that the carbohydrate moiety of the protein may have a role in estrogen-AFP interactions.

Animals↗
PubMed1976

[Preparation and immunoephelometric quantitation of fibrinogen in rabbits].

Pure rabbit fibrinogen was prepared by a method involving two ammonium sulfate precipitations, one 2 M phosphate buffer precipitation, one DEAE cellulose chromatography and lastly one Sepharose 6 B chromatography. The aminoacid composition was determined and an immunonephelemetric assay was proposed. This assay followed an accurate determination of fibrinogen concentration in a rabbit with inflammatory reaction.

Amino Acids↗
PubMed1975

Isolation of two forms of rat alpha-fetoprotein and comparison of their binding parameters with estradiol-17beta.

In polyacrylamide gels, highly purified rat alpha1-fetoprotein shows a molecular heterogeneity, i.e. a "slow" and a "fast" moving fraction. We have isolated by electrophoretic fractionation and subsequent elution these two forms of alpha1-fetoprotein, and we have studied comparatively the binding parameters for estradiol-17beta of whole alpha1-fetoprotein preparations and of the isolated forms. We have shown that the number of binding sites per molecule of whole alpha1-fetoprotein is always, in our experimental conditions, a fractional number, inferior to unity (0.3). Furthermore, the analysis of the binding parameters of the "two forms" of alpha1-fetoprotein allows discrimination between different classes of binding sites. For the "slow" fraction, the number of predominant binding sites per molecule of protein is close to unity (0.7-0.9), whereas for the "fast" fraction, a very low fractional value is found (0.1). The corresponding association constants are reproducibly different for the two fractions: Ka = 0.1.10(8) M-1 for the "slow" alpha1-fetoprotein, and Ka = 0.7.10(8) M-1 for the "fast" alpha1-fetoprotein. Traces of a very high affinity (10(9) M-1) minor class of binding sites are demonstrated in the "slow" fraction. These results point to the existence of a molecular population of alpha1-fetoprotein, some forms of which have a strong or very strong affinity, and some a negligible affinity, for estrogens.

Animals↗