Specific antisera for the radioimmunoassay of estriol 3-sulfate

Lifespan effects in male UM-HET3 mice treated with sodium thiosulfate, 16-hydroxyestriol, and late-start canagliflozin

Genetically heterogeneous UM-HET3 mice born in 2020 were used to test possible lifespan effects of alpha-ketoglutarate (AKG), 2,4-dinitrophenol (DNP), hydralazine (HYD), nebivolol (NEBI), 16α-hydroxyestriol (OH_Est), and sodium thiosulfate (THIO), and to evaluate the effects of canagliflozin (Cana) when started at 16 months of age. OH_Est produced a 15% increase (p = 0.0001) in median lifespan in males but led to a significant (7%) decline in female lifespan. Cana, started at 16 months, also led to a significant increase (14%, p = 0.004) in males and a significant decline (6%, p = 0.03) in females. Cana given to mice at 6 months led, as in our previous study, to an increase in male lifespan without any change in female lifespan, suggesting that this agent may lead to female-specific late-life harm. We found that blood levels of Cana were approximately 20-fold higher in aged females than in young males, suggesting a possible mechanism for the sex-specific disparities in its effects. NEBI was also found to produce a female-specific decline (4%, p = 0.03) in lifespan. None of the other tested drugs provided a lifespan benefit in either sex. These data bring to 7 the list of ITP-tested drugs that induce at least a 10% lifespan increase in one or both sexes, add a fourth drug with demonstrated mid-life benefits on lifespan, and provide a testable hypothesis that might explain the sexual dimorphism in lifespan effects of the SGLT2 inhibitor Cana.

Male lifespan extension with 17-α estradiol is linked to a sex-specific metabolomic response modulated by gonadal hormones in mice

Longevity in mammals is influenced by sex, and lifespan extension in response to anti‐aging interventions is often sex‐specific, although the mechanisms underlying these sexual dimorphisms are largely unknown. Treatment of mice with 17‐α estradiol (17aE2) results in sex‐specific lifespan extension, with an increase in median survival in males of 19% and no survival effect in females. Given the links between lifespan extension and metabolism, we performed untargeted metabolomics analysis of liver, skeletal muscle and plasma from male and female mice treated with 17aE2 for eight months. We find that 17aE2 generates distinct sex‐specific changes in the metabolomic profile of liver and plasma. In males, 17aE2 treatment raised the abundance of several amino acids in the liver, and this was further associated with elevations in metabolites involved in urea cycling, suggesting altered amino acid metabolism. In females, amino acids and urea cycling metabolites were unaffected by 17aE2. 17aE2 also results in male‐specific elevations in a second estrogenic steroid—estriol‐3‐sulfate—suggesting different metabolism of this drug in males and females. To understand the underlying endocrine causes for these sexual dimorphisms, we castrated males and ovariectomized females prior to 17aE2 treatment, and found that virtually all the male‐specific metabolite responses to 17aE2 are inhibited or reduced by male castration. These results suggest novel metabolic pathways linked to male‐specific lifespan extension and show that the male‐specific metabolomic response to 17aE2 depends on the production of testicular hormones in adult life.

Bridge-heterologous chemiluminescence enzyme-linked immunosorbent assay of estriol 3-sulfate in pregnancy plasma

A facile and sensitive chemiluminescence enzyme-linked immunosorbent assay (ELISA) of estriol 3-sulfate using a bridge-heterologous system was established. 6 alpha-Hydroxyestriol 3-sulfate 6-hemisuccinate was synthesized as a novel hapten. Antisera were raised in male guinea-pigs against 6 alpha-hydroxyestriol 3-sulfate 6-hemisuccinate-bovine serum albumin (BSA) and 6-oxoestriol 3-sulfate O-carboxymethyloxime-BSA conjugates. Both haptens were coupled to horseradish peroxidase as an enzyme-label reagent. For separation of free and estriol 3-sulfate bound to the antibody, the crude globulin fractions of these antisera were immobilized to CNBr-activated Sepharose-4B. The enzyme activity was measured by chemiluminescent reaction using amino-butylethylisoluminol and hydrogen peroxide as a substrate. The immobilized antibody raised against 6 alpha-hydroxyestriol 3-sulfate 6-hemisuccinate-BSA exhibited a high affinity and an excellent specificity for estriol 3-sulfate. The two bridge-heterologous ELISAs were more sensitive than the homologous systems. The specificity and sensitivity (10 pg) of the bridge-heterologous chemiluminescence ELISAs was comparable to those of the radioimmunoassays (RIAs). Results obtained by the ELISA and the RIA in pregnancy plasmas, showed excellent correlation between ELISA and RIA (r = 0.96).

Specific imaging of hormone-dependent mammary carcinoma in nude mice with [131I]-anti-estriol 3-sulfate antibody

We tried to put the estrogen metabolite to use in tumor imaging. The antibody against estriol 3-sulfate (E3 3-S), which was one of the major metabolites of estrogen in hormone-dependent mammary carcinoma, was prepared and the tissue distribution and imaging of human breast carcinoma with anti-E3 3-S antibody (Ab) were studied in nude mice. In hormone-dependent breast carcinoma, MCF-7,-bearing nude mice, [125I] anti-E3 3-S Ab localized in tumor with the percentage injected dose/g of 9.29 +/- 3.01 (mean +/- SD). This value was significantly high compared with that in hormone-independent breast carcinoma, MDA-MB-231,-bearing nude mice. At 72 h after the administration of [125I]anti-E3 3-S Ab to MCF-7 bearing mice, tumor/blood, tumor/liver and tumor/muscle ratios were 0.49, 5.02 and 6.83, respectively. These ratios were supposed to be enough for imaging. In radioimmunoscintigraphy, a MCF-7 tumor was clearly visualized at 120 or 168 h post-injection of [131I]anti-E3 3-S Ab.

Determination of estrogen 3-sulfates in biological fluids of mammary tumor-bearing rats by radioimmunoassay

Determination of estradiol 3-sulfate (E2 3-S) and estriol 3-sulfate (E3 3-S) in plasma, urine or tumor tissues of mammary tumor-bearing rats were performed using the superior radioimmunoassay (RIA) system. The plasma level of E2 3-S after tumorigenesis was found to be about one-third of the normal level. As to E3 3-S, the levels in urine were significantly high both before and after tumorigenesis. Before that, the average level was about 1.5 times, and after that, about 2.5 times as high as the normal level. In tumor tissues, an extremely high level of E3 3-S (399.6 +/- 113.9 pg/g tissue) was determined.

Mammary tumor immunoscintigraphy in rats: the use of 131I-anti-estriol 3-sulfate antibody

The scintigraphic imaging of mammary tumors with anti-estriol 3-sulfate (E3 3-S) antibody was studied in rats. A chemical carcinogen, 7,12-dimethylbenz(a)anthracine (DMBA), induced mammary tumors in Sprague-Dawley female rats. Highly specific anti-E3 3-S antibody was prepared and radioiodinated by [131I]NaI using the chloramine-T method. At 24 h after administration of 131I-anti-E3 3-S antibody, goat anti-guinea pig immunogloblin G (IgG) was injected as the second antibody (SA) and nuclear scintigraphy was performed. Mammary tumors were clearly visualized following SA injection.

Determination of estradiol-17-sulfate in human urine by a direct radioimmunoassay: urinary levels throughout the menstrual cycle

The measurement of urinary estradiol-17-sulfate concentration by direct radioimmunoassay was established. The urinary estradiol-17-sulfate levels measured by the radioimmunoassay correlated well with those determined by high-performance liquid chromatography equipped with electrochemical detector. Estradiol-17-sulfate concentrations in early morning urine of six healthy adult men was 8.2 +/- 2.0 ng/mL, or 5.7 +/- 1.8 ng/mg creatinine. The urinary levels in women throughout the menstrual cycle showed a characteristic three-peak excretion pattern: the first and the second peaks appeared just after and three days before the urinary LH peak, and the third peak appeared a few days before menstruation.

A radioimmunoassay for deoxycorticosterone sulfate without hydrolysis

The hapten of deoxycorticosterone sulfate was synthesized and linked to the carrier protein through the C-4 position on the steroid nucleus. The antisera raised against this antigen in guinea pigs exhibited high affinity (Ka = 1.86 x 10(9) M-1) and excellent specificity for deoxycorticosterone sulfate. It was found that deoxycorticosterone sulfate can be determined in the range of 50-5000 pg, and this radioimmunoassay in plasma shows a coefficient of variation (CV) less than 10%.

A simple radioimmunoassay for estriol 3-sulfate in pregnancy plasma without deconjugation

A highly specific anti-estriol 3-sulfate antiserum was treated with 50% ammonium sulfate, and the crude globulin fraction was coupled to CNBr-activated Sepharose-4B. Addition of 0.1M Tris-HC1 buffer (pH 8.3) containing 0.1M glutamine to the solution of antigen-antibody enabled assaying without solvent-extraction or chromatography to remove endogenous interference. Subsequently, a direct radioimmunoassay using [6,7-3H]-estriol 3-sulfate as a radioactive ligand without deconjugation has been established and applied to the determination of estriol 3-sulfate levels in pregnancy plasma. The increasing plasma levels of estriol 3-sulfate are correlated with estriol levels over the period of gestation. The mean values of sulfated estriol concentration (A) in late pregnancy plasma were approximately 7 times as high as unconjugated estriol (B), but individual ratios of A to B showed considerable variability.