Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

The comparative specificity of 3 oestradiol-binding proteins. Rat alpha-foetoprotein, rat liver 17beta-hydroxy steroid dehydrogenase and anti-(oestradiol-6-carboxymethyloxime-bovine serum albumin) antiserum.

ABSTRACT: 1. The specificity of 3 oestradiol-binding proteins was studied. Two of these proteins are naturally occurring (rat alpha-foetoprotein and rat liver microsomal 17beta-hydroxy steroid dehydrogenase) and the third is an artificially induced model, anti-(oestradiol-6-carboxymethyloxime-bovine serum albumin) gamma-globulins. 2. A specific binding procedure for each protein model permitted a determination of its affinity for oestradiol and for 30 other steroids. 3. The results obtained have brought to light the different areas of the steroid molecule that are important for its recognition by each of the three proteins. The two naturally occurring proteins (alpha-foetoprotein and 17beta-hydroxy steroid dehydrogenase) recognize the edge of the steroid defined by C-4, C-6, C-8 and C-15. On the other hand, the gamma-globulins recognize the opposite edge, i.e. that defined by C-2, C-10, C-11 and C-17. 4. Diethylstilboestrol, whose structure is analogous to that of a steroid, is only recognized by the two naturally occurring proteins.

SUBMITTER: Laurant C

PROVIDER: S-EPMC1172398 | biostudies-other | 1975 Dec

REPOSITORIES: biostudies-other

ACCESS DATA

Json Xml

Similar Datasets

The specificity of a 7 alpha-hydroxy steroid dehydrogenase from Escherichia coli.

Project description:1. Thirty-eight steroids were tested as substrates for a 7 alpha-hydroxy steroid dehydrogenase preparation from a strain of Escherichia coli; an improved method of making the crude enzyme is described. 2. Steroids having a 7 alpha-hydroxyl group in the molecule were substrates except (a) when the 5 beta-cholan-24-oic acid side chain was shortened to less than four carbon atoms and (b) in certain cases when sulphate ester groups were present in the molecule. 3. For testing with the enzyme, a new specimen of 7 alpha-hydroxy-3,12-dioxo-5 beta-cholan-24-oic acid was made, which had properties different from those previously described.

| S-EPMC1163832 | biostudies-other

Arginine-140 and isoleucine-141 determine the 17beta-estradiol-binding specificity of the sex-steroid-binding protein (SBP, or SHBG) of human plasma.

Project description:Arginine-140 and isoleucine-141 were identified as key determinants of 17beta-estradiol (E(2)) binding affinity of the sex-steroid-binding protein (SBP, or SHBG) of human plasma. Amino acid residues that differ between human and rabbit SBP sequences were replaced in the human protein and the products tested for lowered E(2)binding activity as are seen in the rabbit protein. Only mutants containing either R140K or I141L replacements display an E(2) equilibrium dissociation constant (Kd) higher than the wild type, reaching a value of 30 nM when both were present. The 5alpha-dihydrotestosterone (DHT) equilibrium dissociation constant of these mutants was unaffected. The quadruple mutant M107I/I138V/R140K/I141L yielded an E(2) Kd of 65 nM, significantly closer to the 80 nM rabbit SBP E(2) Kd value. Although mutants containing the M107I and I138V replacements in the absence of R140K and I141L had normal E(2) Kds, the presence of the M107I replacement in the quadruple mutant was necessary to obtain an accurate E(2) Kd value by competitive Scatchard analysis. Molecular modeling using coordinates for the recently determined N-terminal domain of human SBP revealed a significant shift of the F56 phenyl ring away from ring A of E(2) in mutant models containing the R140K and I141L replacements. We conclude that R140 and I141 are required for sustaining the right proximity of the phenyl ring of F56 to ring A of 17beta-estradiol, thus optimizing the E(2)-binding affinity of human SBP.

| S-EPMC2253199 | biostudies-literature

Hormonal control of Luteal 20alpha-Hydroxy steroid dehydrogenase and delta5-3beta-hydroxy steroid dehydrogenase during luteolysis in the pregnant rat.

Project description:Treatment of pregnant rats with human chorionic gonadotrophin, luteotrophin (luteinizing hormone), luteotrophin-releasing hormone, prostaglandin F2alpha, aminoglutethimide, or by foetoplacental removal or hysterectomy achieved a common multiple-response pattern, namely increased activity of luteal 20alpha-hydroxy steroid dehydrogenase with decreased activity of delta5-3beta-hydroxy steriod dehydrogenase and release of delta4-3-oxo steroids in vitro. 2. Similar effects of foetoplacental removal are noted in pregnant mice. 3. Gonadotrophin induced lower activities of 20alpha-hydroxy steroid dehydrogenase, except at the very end of pregnancy, and partly inhibited the induction caused by foetoplacental removal. 4. The results suggest that existence of a placental factor that restrains these changes until the end of normal pregnancy, which is produced in amounts proportional to the number of placentae and is conveyed to the ovary via the blood. 5. This factor was not replaced by prolactin. 6. It is argued that neither placental lactogen nor pituitary luteotrophin participate in the induction of 20alpha-hydroxy steroid dehydrogenase at late pregnancy in the rat. 7. Aminoglutethimide induced 20alpha-hydroxy steroid dehydrogenase only in late pregnancy. This was partly reversed by progesterone, wholly reversed by progesterone plus oestrogen, and did not involve the pituitary.

| S-EPMC1172495 | biostudies-other

Histone acetylation and hormone action. Early effects of oestradiol-17beta on histone acetylation in rat uterus.

Project description:The effect of oestradiol treatment on the acetylation of histones of the immature rat uterus has been studied. A 10mug dose of oestradiol causes a 70% increase at 5min and a 140% increase at 10min after administration in the labelling of the histone fraction F2+F3. No effect of oestradiol is seen on the labelling of histones F1 or acidic non-histone chromatin proteins. The oestradiol stimulation is seen in animals pretreated with either cycloheximide or actinomycin D. The stimulation of labelling caused by oestradiol is completely abolished by pretreatment of the animals with the anti-oestrogen, nafoxidine. The stimulation is given by lower doses of oestradiol, by stilboestrol and oestriol, but is not given by testosterone. These results suggest that stimulation of histone acetylation in the uterus is the earliest known effect of the hormone on its target tissue.

| S-EPMC1174504 | biostudies-other

Nuclear binding of oestradiol-17beta and induction of protein synthesis in the rat uterus during postnatal development.

Project description:1. The uterine response to a single injection of oestradiol-17beta during postnatal development of the rat was studied with respect to (i) nuclear binding of oestradiol-17beta; (ii) induction of the synthesis of a specific cytoplasmic protein (;induced protein' of Gorski); (iii) rate of incorporation of (3)H-labelled amino acids into total protein and into nuclear acid-soluble and acid-insoluble protein; and (iv) rate of [(3)H]thymidine incorporation into DNA. 2. Specific nuclear binding of oestradiol-17beta could be demonstrated even at birth. Administration of oestradiol-17beta in vivo caused a significant increase in the number of nuclear binding sites in rats aged 10 days or older. 3. A rapid method is described for the detection of the ;induced protein', based on cellulose acetate electrophoresis. Induction of this protein could be demonstrated at the age of 10, 15 and 20 days, but not in 5-day-old rats. 4. In 20-day-old rats the rate of (3)H-labelled amino acid incorporation into protein increased by 3h after oestradiol administration. Incorporation into the different protein fractions reached peak values asynchronously: at 3-4h for acid-insoluble nuclear protein, at 6h for total protein and at about 12h for acid-soluble protein. 5. Treatment with oestradiol failed to stimulate amino acid incorporation into protein in 5- or 10-day-old rats; at the age of 15 to 30 days the hormone caused a significant increase in incorporation into total protein and into both types of nuclear protein. 6. Since the capacity for nuclear binding of oestradiol and for synthesis of the induced protein is demonstrable in the rat uterus before it acquires the ability to respond to the hormone with enhanced general protein synthesis and DNA synthesis, it appears that nuclear binding and the synthesis of the induced protein may be necessary but not sufficient conditions for the trophic action of oestradiol.

| S-EPMC1165921 | biostudies-other

Participation of the lone tryptophan residue of rat alpha-foetoprotein in its drug-binding sites. Comparison with rat serum albumin.

Project description:The participation in drug binding of the lone tryptophan residue of rat alpha-foetoprotein (alpha-FP) and serum albumin, the two main transport proteins of foetal serum, has been studied by two different techniques. Firstly, the effect on phenylbutazone and warfarin binding of the chemical derivatization of the lone tryptophan residue of both proteins by 2-nitrophenylsulphonyl chloride (NPS) was studied. Secondly, the effect of phenylbutazone binding on the intrinsic fluorescence of the tryptophan residue of rat alpha-FP and albumin was investigated. The specific modification of the proteins by NPS did not affect the binding of warfarin by rat alpha-FP and albumin, but greatly decreased the affinity of the high-affinity sites of rat alpha-FP for phenylbutazone, though the numbers of these sites were not significantly changed. However, for albumin a similar decrease in the affinity constant appeared to be due to the reaction conditions. The spectrofluorimetric studies showed that the lone tryptophan residue of alpha-FP and albumin was quenched by phenylbutazone binding, and the quenching paralleled the fractional saturation of the high-affinity site only in the case of albumin. The effect of phenylbutazone binding on the intrinsic fluorescence of rat alpha-FP indicated that the lone tryptophan residue of this foetal protein is not in the same molecular environment as that of albumin, not participating directly in the high-affinity site for phenylbutazone, and the effect may be via some induced conformational change in rat alpha-FP. These results also confirm our previous suggestion that the high-affinity sites for phenylbutazone and warfarin are different on the rat alpha-FP molecule. The results seem to indicate that this is also the case for albumin, but confirmation is necessary.

| S-EPMC1147956 | biostudies-other

3 -Hydroxy steroid dehydrogenase activity in the mitochondria of rat adrenal homogenates.

Project description:The activity of 3beta-hydroxy steroid dehydrogenase (EC 1.1.1.51) in the mitochondrial fraction of rat adrenal homogenates was approx. 31% of the total activity recovered after differential centrifugation and washing of the particulate fractions. Some 45% of the total activity was found in the microsomal fraction. The activity was assayed by a radioisotopic method devised in this laboratory for the purpose of studying small quantities of tissue and cell fractions. Satisfactory separation of the two fractions was demonstrated by electron microscopy of the pellets and by comparative recoveries of RNA, steroid 21-hydroxylase and cytochrome c oxidase in the various compartments. Analyses of the kinetics of the enzyme activity in the two fractions revealed no significant differences in apparent K(m) for pregnenolone, dehydroepiandrosterone or NAD(+), but demonstrated a distinct difference in the K(m) for NADP(+). pH optima and susceptibility to cyanoketone inhibition were similar in both fractions.

| S-EPMC1178260 | biostudies-other

17Beta-Estradiol Inhibits Calcium-Activated Potassium Channel Expressions in Rat Whole Bladder.

Project description:PURPOSE:To investigate the effect of estrogen on the expression of calcium-activated potassium (KCa) channels in an overactive bladder rat model. To this end, mRNA and protein levels of KCa channel subtypes in the bladder of ovariectomized rats were measured by reverse transcription polymerase chain reaction and western blotting, respectively. METHODS:Ten-week-old female Sprague-Dawley rats were divided randomly into 3 groups: sham-operated control group (n=11), ovariectomy group (n=11), and the group treated with estrogen after ovariectomy (n=12). Rats in the last group were subcutaneously injected with 17?-estradiol (50 ?g/kg) every other day for 2 weeks, whereas rats in the other 2 groups received vehicle (soybean oil) alone. Two weeks after treatment, the whole bladder was excised for mRNA and protein measurements. RESULTS:Protein levels of the large-conductance KCa (BK) channels in the ovariectomy group were 1.5 folds higher than those in the sham-operated control group. However, the protein levels of the other KCa channel subtypes did not change significantly upon bilateral ovariectomy. Treatment with 17?-estradiol after ovariectomy restored BK channel protein levels to the control value. In contrast, BK channel mRNA levels were not significantly affected by either ovariectomy alone or 17?-estradiol treatment. The small-conductance KCa type 3 channel (SK3) mRNA and protein levels decreased to 75% of control levels upon 17?-estradiol treatment. CONCLUSIONS:These results suggest that 17?-estradiol may influence urinary bladder function by modulating BK and SK3 channel expression.

| S-EPMC4819160 | biostudies-literature

Neural expression and post-transcriptional dosage compensation of the steroid metabolic enzyme 17beta-HSD type 4.

Project description:Steroids affect many tissues, including the brain. In the zebra finch, the estrogenic steroid estradiol (E2) is especially effective at promoting growth of the neural circuit specialized for song. In this species, only the males sing and they have a much larger and more interconnected song circuit than females. Thus, it was surprising that the gene for 17beta-hydroxysteroid dehydrogenase type 4 (HSD17B4), an enzyme that converts E2 to a less potent estrogen, had been mapped to the Z sex chromosome. As a consequence, it was likely that HSD17B4 was differentially expressed in males (ZZ) and females (ZW) because dosage compensation of Z chromosome genes is incomplete in birds. If a higher abundance of HSD17B4 mRNA in males than females was translated into functional enzyme in the brain, then contrary to expectation, males could produce less E2 in their brains than females.Here, we used molecular and biochemical techniques to confirm the HSD17B4 Z chromosome location in the zebra finch and to determine that HSD17B4 mRNA and activity were detectable in the early developing and adult brain. As expected, HSD17B4 mRNA expression levels were higher in males compared to females. This provides further evidence of the incomplete Z chromosome inactivation mechanisms in birds. We detected HSD17B4 mRNA in regions that suggested a role for this enzyme in the early organization and adult function of song nuclei. We did not, however, detect significant sex differences in HSD17B4 activity levels in the adult brain.Our results demonstrate that the HSD17B4 gene is expressed and active in the zebra finch brain as an E2 metabolizing enzyme, but that dosage compensation of this Z-linked gene may occur via post-transcriptional mechanisms.

| S-EPMC2858028 | biostudies-literature

17beta-oestradiol increases intracellular Ca2+ concentration in rat enterocytes. Potential role of phospholipase C-dependent store-operated Ca2+ influx.

Project description:The involvement of the phospholipase C (PLC) pathway in the non-genomic regulation of duodenal cell Ca2+ concentration by 17beta-oestradiol was investigated. The PLC inhibitors neomycin (0.5 mM) and U-73122 (2 microM) suppressed the stimulatory effect of 0.1 nM 17beta-oestradiol on the 45Ca2+ influx into enterocytes isolated from rat duodenum. The hormone (1 pM to 10 nM) increased the formation of 1,2-diacylglycerol in a biphasic pattern, characterized by an early peak at 45 s (+82%) and a later peak at 5 min (+46%). Both PLC inhibitors suppressed the first peak but were unable to block the 17beta-oestradiol effect at 5 min. 17beta-Oestradiol also increased the generation of inositol 1,4,5-trisphosphate within 15 s, with maximal stimulation at 30 s. 17beta-Oestradiol induced a rapid (30 s) and sustained (up to 5 min) increase in the intracellular Ca2+ concentration ([Ca2+]i) of fura 2-loaded enterocytes. The fast rise in [Ca2+]i was specific because other sex steroid hormones were without effect and could be blocked to a great extent by U-73122 (by 86% at 1 min). The effects of 17beta-oestradiol on enterocyte [Ca2+]i were decreased significantly (by 75%) in a Ca2+-free extracellular medium but a pronounced increase in [Ca2+]i was obtained after readmission of Ca2+ to the medium. The latter change was suppressed by 10 microM La3+, whereas nitrendipine (1 microM) and verapamil (10 microM) separately were without effect. The permeability of the 17beta-oestradiol-induced Ca2+ influx pathway to Mn2+ was increased 2.8-fold by treatment with oestrogen. These results suggest the operation of a PLC-dependent store-operated Ca2+ channel mechanism in 17beta-oestradiol regulation of enterocyte extracellular Ca2+ influx.

| S-EPMC1220129 | biostudies-other

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data