Fluorescence and Absorption Spectra of Estrogens Heated in Sulfuric Acid

Slaunwhite, W. Roy; Engel, Lewis L.; Scott, Jesse F.; Ham, Claire L.

doi:10.1016/s0021-9258(18)66217-9

Cited by 43 publications

(1 citation statement)

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“…The reaction of estrogens with a dehydrating agent such as sulfuric acid results in the formation of fluorescent substances [ 15 ]. The wavelengths of maximal fluorescence of estrone, estradiol-17β, and equilin generated by the reaction with sulfuric acid were 480 to 484 nm, 458 to 487 nm, and 563 to 566 nm, respectively [ 16 ]. In the present study, urinary fluorescence was detected using an interference filter with a 535 nm center wavelength passing and a 25 nm width at half maximum.…”

Section: Discussionmentioning

confidence: 99%

Development of a fluorometric Cuboni test for the semi-quantitative measurement of urinary estrogen levels and pregnancy detection in mares

ODA,

YOSHIDA,

IRSHAD

et al. 2024

Journal of Reproduction and Development

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The aim of the present study was to develop a semi-quantitative urine pregnancy test for mares based on the Cuboni reaction and to verify the reliability of this test. The urine specimens were hydrolyzed by heating in the presence of hydrochloric acid. The resulting free estrogens were extracted from the urine matrix using toluene. Sulfuric acid was added to the toluene extract and the mixture was heated again. The lower layer in the test tube containing sulfuric acid was used for fluorescence measurements with excitation at 355 nm and measurement at 535 nm. The fluorometric Cuboni test revealed that the fluorescence counts in urine samples collected after the second trimester of gestation were significantly higher than those obtained from barren mares. The levels of estrogens, including equilin, estrone and estardiol-17β exhibited a dose-dependent increase in fluorescence counts, whereas other steroids, such as progesterone, testosterone, and cortisol, did not affect fluorescence. Heat treatment of urine samples with hydrochloric acid significantly increased the fluorescence counts in those collected after the second trimester of gestation compared to non-pregnant samples, implying the presence of large amounts of conjugated estrogens in pregnant mare urine. Fluorescence counts in urine samples obtained during pregnancy showed a positive relationship with estrone concentrations as measured by enzyme immunoassay. The results of the present study showed that the fluorometric Cuboni test facilitates urine fluorescence counts depending on the urinary estrogen content and is capable of discriminating between pregnancy and non-pregnancy states beyond the second trimester of gestation in mares.

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Section: Discussionmentioning

confidence: 99%