Biomedical subjects

A Marandici

Publications and source records attributed to A Marandici.

10 recordsLinked to original sources

PubMed1991

Corticosteroid side-chain isomerase in the circulatory system.

Corticosteroid side-chain (CSC) isomerase catalyzes ketol-aldol interconversion of the corticosteroid side chain. The enzyme was present in the blood of mouse, rat, guinea pig, chicken, pig, horse, sheep, cow, and human. The patterns of substrate specificity, measuring 3H-1H exchange of 21-tritiated forms of 11-deoxycorticosterone, corticosterone, and cortisol, were species specific. Based on enzyme activity and immunostaining of mouse blood fractions, red blood cells had the most isomerase activity, plasma had less, and white blood cells had low but highly variable levels of enzyme. Purified mouse liver CSC isomerase was found to be adsorbed by red blood cells. The results suggest that circulating CSC isomerase is derived in part from tissue sources and is in part an intrinsic blood enzyme.

Animals↗

PubMed1990

Purification and characterization of corticosteroid side chain isomerase.

Corticosteroid side chain isomerase of rat liver catalyzes the interconversion of the ketol (20-oxo-21-ol) and aldol (20-hydroxy-21-al) forms of the corticosteroid side chain. The enzyme has now been purified to apparent homogeneity from rat liver cytosol by sequential chromatography on anionic, hydroxylapatite, and gel filtration columns. Ketol-aldol isomerization is followed by measuring the exchange of tritium from 21-tritiated steroids with water. The native enzyme is a dimer of MW 44,000. The isoelectric point is 4.8 +/- 0.1 pH units. The purified enzyme is stimulated by Co3+ or Ni2+. The enzyme utilizes 11-deoxycorticosterone, corticosterone, and 17-deoxycortisol as substrate but not cortisol, tetrahydrocortisol, and prednisolone. Tritium-water exchange of (21S)-[21-3H]DOC is a pseudo-first-order reaction; 21-3H exchange from the 21R isomer proceeds with first-order kinetics only after a lag associated with its epimerization to the 21S form.

Amino Acids↗

PubMed1990

Corticosteroid side-chain isomerase in mouse organs: kinetic and immunologic studies.

We have investigated the distribution of corticosteroid side-chain (CSC) isomerase in the tissues of mice using as criteria its enzyme activity and immunoreactivity with monospecific polyclonal antibodies generated in rabbits. CSC isomerase was present in all organs examined. The liver and kidney contained the highest activity. The strain-dependent differences that we had previously reported for liver (i.e., BALB/c greater than C57BL/6) extended to the other organs, including the kidney, brain, heart, muscle, pancreas, testis, thymus, and lung. Western blot analysis showed a single antigen, identical in all tissues, corresponding in mobility to purified CSC isomerase. The intensities of the bands were generally proportional to enzyme activities. Titration of homogeneous enzyme with the IgG fraction of antiserum (unfractionated serum had some CSC isomerase activity) caused an increase in activity, followed by rapid inactivation after the addition of more antiserum. The broad distribution of CSC isomerase suggests that the ketol-aldol interconversion of the CSC may play a role other than, or in addition to, initiating metabolic inactivation of corticosteroids.

Animals↗

PubMed1989

Synthesis of tritium labeled cortoic acids.

A procedure is described for the microsynthesis and purification of the high specific activity tritium labeled cortisol metabolites, 20 alpha- and 20 beta-cortolic acids and 20 alpha- and 20 beta-cortolonic acids.

Cortisone↗

PubMed1986

Estrogen and progesterone receptors in the organs of prenatal cynomolgus monkey and laboratory mouse.

The estrogen and progesterone receptors of several organs of the prenatal cynomolgus macaque and the fetal mouse were studied using a combination of the dextran-coated charcoal technique and high-performance liquid chromatography. This procedure permitted the concurrent measurement of both receptors in minute amounts of tissue. Estrogen receptors, but not progesterone receptors, were found in the fetal monkey and mouse uteri. No estrogen or progesterone receptors were detected in the lungs, liver, kidney, heart, brain, adrenal gland, or limbs of mouse or monkey fetuses. The nonspecific binding of radioactive ORG-2058 was not displaced by unlabeled progesterone, 17 alpha-hydroxyprogesterone caproate, or ORG-2058. Because the steroid receptors that are indispensable mediators of steroid hormone action were absent from the nonreproductive tissues, prenatal development of these organs and tissues cannot be adversely influenced by exposure to estradiol, progesterone, or their synthetic analogues.

17 alpha-Hydroxyprogesterone Caproate↗

PubMed1985

Comparison of the distribution kinetics and metabolism to acid end-products of corticosterone and 11-deoxycorticosterone in BALB/c mice.

The conversion of [4 14C]corticosterone[( 14C]B) and 11-deoxy-[1,2-3H]corticosterone [( 3H]DOC) to steroidal carboxylic acids was studied in the BALB/c mouse. There was rapid and preferential excretion of [3H]DOC metabolites into the gastrointestinal tract. Excretion of 14C through the kidney was higher than 3H excretion. Within minutes of intraperitoneal injection, levels of 3H and 14C in most organs reached their maximal levels and subsequently decreased in an exponential pattern. The majority of the organs took up 14C to a greater extent than 3H. Using tissue blood ratio of tracer (T/B) as criterion, it was found that liver, gall bladder, intestine, and kidney concentrated 3H and 14C-labeled steroid from blood. T/B for 3H exceeded that for 14C in the gastrointestinal tract. Abdominal fat preferentially took up [3H]DOC tracer, whereas [14C]B tracer was not taken up by this tissue. T/B was less than 1 for 3H and 14C in heart, thymus, spleen, brain, skeletal muscle and skin. In these organs uptake of B and its metabolites was greater than that of DOC and its metabolites. In liver, [14C]B and [3H]DOC were converted to carboxylic acid metabolites which accumulated in the intestine. The most abundant acid was 11 beta,20 alpha-dihydroxy-3-oxo-pregn-4-en-21-oic acid from B. The acid metabolites of DOC were not identified. For both steroids, acids were major metabolic end-products.

Animals↗

PubMed1984

The fate of corticosterone and 11-deoxycorticosterone in C57BL/6 and BALB/c strains of mice: distribution and oxidative metabolism.

The distribution kinetics and oxidative metabolism of [4-C14] corticosterone (B) and 11-deoxy-[1,2-3H] corticosterone (DOC) were compared in C57BL/6 (B6) and BALB/c (C) mice. Statistically important differences in the distribution of [14C]B and [3H]DOC occurred that were independent of strain, while other differences were strain dependent. Intestinal excretion of metabolites of B and DOC was greater in B6 mice than in C mice, and kidney excretion was greater in C mice than B6 mice. In both C and B6 mice, 3H was cleared from liver faster than 14C, with no strain differences. DOC metabolite levels exceeded B metabolite levels in small intestine and gall bladder of both strains. In most other organs, B metabolites exceeded DOC metabolites. Time average strain differences in accumulation of B and its metabolites favoring B6 were found in pancreas, brain, lung, heart, muscles, adrenals, spleen, mesentery and small intestine. Except for the organs of excretion, no strain differences were found for [3H]DOC metabolites. Sixty minutes after steroid administration, 45% of B metabolites and a third of DOC metabolites were 20-hydroxy-21-oic acids. In the intestine, accumulation of acids derived from either B or DOC was greater for B6 than C strain mice, reflecting the greater proportion of total steroid excreted in the B6 strain.

Animals↗

PubMed1983

Metabolism of corticosterone in the mouse. Identification of 11 beta, 20 alpha-dihydroxy-3-oxo-4-pregnen-21-oic acid as a major metabolite.

We have shown that mouse liver contains enzymes that catalyze the conversion of the ketol side chain to the 20-hydroxy-21-oic acid side chain. In this paper, we have studied the oxidative metabolism of corticosterone to acidic end products in intact mice. A significant fraction of radioactivity from intraperitoneal injections of [4-14C]corticosterone appeared in liver and intestine within 5 min. The major steroid in liver at 5 min postinjection was found to be corticosterone, although acidic metabolites were detected. Within 30 min after injection, 11 beta, 20 alpha-dihydroxy-3-oxo-preg-4-en-21-oic acid became the dominant steroid. At 60 min, it was the major steroid isolated from liver or intestine. Several other acid metabolites were present in lesser amounts in both organs. About half of the remaining radioactive metabolites in liver and intestine were steroid acids, as determined by their reaction with diazomethane. The identification of the major steroid acid as 11 beta, 20 alpha-dihydroxy-3-oxo-pregn-4-en-21-oic acid was made by comparing the chromatographic behavior of the free acid and its methyl ester with that of authentic synthetic acid using thin layer and high performance liquid chromatography. Identity was confirmed by showing that the specific activities of the homogeneous 14C-labeled free acid remained unchanged when reanalyzed as the 21-methyl ester.

Animals↗

PubMed1983

A comparison of the tissue distribution and metabolism of 11-deoxy-[1,2-3H]corticosterone in the BALB/c and C57BL/6 strains of mice.

Corticosteroid side-chain isomerase of mouse liver catalyzes the reversible interconversion of the ketol and aldol configurations of the corticosteroid side chain. Activity of the enzyme is under genetic control. To see if the differences in activity that were observed in vitro between inbred strains of mice were also expressed in vivo, the metabolism of 11-deoxy-[1,2-3H]corticosterone ([1,2-3H]DOC) was studied in BALB/c (C) and C57BL/6 (B6) mice. Maximum radioactivity appeared in most organs within 5-10 min after ip injection. Uptake of tracer into liver was greater for C than B6 mice. Tritium levels in blood, kidney, and pancreas were higher in C mice; levels in adrenal, abdominal fat, and mesentery were higher in B6 mice. In both strains, the concentrations of tracer in tissues, except in gastrointestinal tract, declined and reached a minimum within 60 min. Most of the radioactivity (84%) from [1,2-3H]DOC accumulated in the lumen of the intestinal tract, and few counts were found in the wall. Intestinal concentrations of 3H at different postinjection intervals were greater for B6 than C mice. In contrast, twice as much radioactivity appeared in the kidneys of C than of B6 mice. The organs of excretion (kidney, liver, gall bladder, and intestine) concentrated steroid from blood. Heart, striated muscle, and spleen excluded steroid. Four acidic metabolites of [1,2-3H]DOC were detected in liver, and two were detected in small intestine. Acids formed in liver did not accumulate, and no differences between C and B6 strains were seen. More acid metabolites accumulated in intestines of C mice than in those of B6 mice. The quantitative aspects of steroid acid formation in vivo are consistent with our previous in vitro findings that livers from C mice synthesize more pregnolic acid from DOC than do livers from B6 mice.

Acids↗

PubMedDate not supplied

Corticosteroid-calcium complexes.

Glucocorticoids and calcium ions are shown to interact to yield a complex with properties that are distinct from those of the reactants. Reaction of steroids with Ca2+ appears to require the dihydroxyacetone side chain, since other structures do not react. Evidence for complex formation are: increased aqueous solubility of cortisol when Ca2+ is added to an aqueous or a biphasic aqueous/chloroform (or ethyl acetate) system; increased rate of migration of cortisol during reversed-phase thin-layer chromatography and HPLC; chromatographic comigration of 45Ca2+ and 3H-labeled cortisol; coprecipitation of 45Ca2+-3H-cortisol complexes. After dissociation of the cortisol-calcium complex, the only steroid recovered was cortisol. By the above criteria, the properties of cortisol were not affected by Sr2+, Ba2+, or Mg2+. The cleavage patterns of cortisol in the mass spectrometer corresponded to that of 11 beta-hydroxyandrostenedione when Ca2+ was present, and to cortisol in its absence. We therefore postulate that the structure of the dihydroxyacetone side chain was transiently altered by Ca2+, resulting in a labile C17-C20 bond. These results support our earlier proposal that the chemical and physico-chemical properties of corticosteroids are modified by calcium ions.

Adrenal Cortex Hormones↗