Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0338671 (Steroids)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Following the constant infusion of 6, 7-3-H-estrone glucosiduronate in male dogs for a period of 120 minutes, the radioactive metabolites present in the plasma were separated by solvent partition, DEAE-Sephapadex, Celite partition and thin layer chromatography. The identities of the individual estrogens and estrogen conjugates were confirmed by specific activity determinations after chromatography in several different solvent systems, enzyme hydrolysis and steroids and their derivatives. Most of the radioactivity in the plasma was identified as estrone glucosiduronate. The major metabolite present was estradiol-17-beta-3-glucosiduronate. Small amounts of estradiol-17-alpha-3-glucosiduronate and free estrone were also identified. Three other minor conjugates were separated, but positive identification could not be made.
Steroids 1975 Mar
PMID:Identification of some plasma metabolites of 6, 7-3-H-estrone glucosiduronate in male dogs. 16 76

A single dose of tritiated estradiol-17 beta (3H-E2 beta) was injected i.v. into 5 high egg producing White Leghorn hens, 31 weeks of age, at 19.2 +/- 2.1 (mean +/- S.D.) hr before oviposition. Blood (2 ml) was sampled at approximately 5 min intervals over 40 min. Whenever possible, metabolites were monitored and identified by the double isotope technique with the addition of the corresponding 14C-labelled standards to plasma prior to analysis. The metabolic half-life and clearance rate of 3H-E2 beta in plasma were 10.9 +/- 1.9 min and 118 +/- 18 ml/min/kg body weight, respectively. The calculated production rate of E2 beta at 19.2 hr before oviposition was 19.5 +/- 5.7 ng/min based on the plasma level (93 +/- 22 pg/ml) measured at that time. The relative concentrations (% of plasma radioactivity) of the major metabolites isolated at 5.7 +/- 0.6 min post injection were, in descending order: estradiol-17 beta-3-sulfate (E2 beta-3S: 14.9 +/- 2.7), estradiol-17 alpha-3-sulfate (E2 alpha-3S; 5.7 +/- 0.3), estrone (E1; 4.6 +/- 0.5), estrone sulfate (E1S; 2.2 +/- 0.5), and estradiol-17 alpha (E2 alpha; 1.2 +/- 0.4). As time proceeded, the relative concentration of E2 alpha-3S gradually increased so that by 43.2 +/- 1.0 min it became the most abundant identifiable metabolite (12.3 +/- 1.1) followed by E2 beta-3S (9.1 +/- 1.7), E1S (1.2 +/- 0.6), E1 (0.7 +/- 0.4) and E2 alpha (0.3 +/- 0.2). These findings are consistent with the view that one of the major pathways of E2 beta metabolism in the circulation of the hen is via E2 beta in equilibrium E2 beta-3S in equilibrium E1S in equilibrium E2 alpha-3S.
Steroids 1984 Jan
PMID:Production, clearance rates and metabolic fate of estradiol-17 beta in the plasma of the laying hen. 652 33

In the presence of a functional corpus luteum, positive estrogen feedback on the surge modes of gonadotropin secretion is blocked in rhesus monkeys. We investigated the effects of luteectomy (Lx) on the time required for recovery of pituitary responsiveness (LH/FSH surges) to positive estrogen feedback. Estradiol-17 beta-3- benzoate (EB, 50 microgram/kg sc) was given: 1) 24th prior to, 2) the day of, or 3) 24 h after luteal ablation. Daily measurements of serum follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol-17 beta (e2) and progesterone (P) were made on each monkey for 5 days. Serum P fell to undetectable levels within 24 h after Lx, whereas E2 levels in circulation peaked within 24h after injection of EB. Among early follicular phase monkeys, this EB treatment results in typical midcycle type LH/FSH surges within 48h. Lx alone was not soon followed by significant changes in pituitary gonadotropin secretion. When circulating P levels were undetectable the pituitary responded fully to EB; that is, typical midcycle type FSH/LH surges occurred. When serum P was in the midst of declining after Lx, gonadotropin surges were present, but attenuated. However, when P levels remained elevated for more than 24 h after EB injection, the surge modes of FSH/LH secretion remained fully blocked. These results demonstrate that the suppressive influence of luteal secretions (principally progesterone) on positive estrogen feedback regulation of the surge modes of pituitary gonadotropin secretion is quite transient in these primates.
Steroids 1980 Sep
PMID:Rapid recovery of estrogen-induced pituitary gonadotropin surges after luteectomy in rhesus monkeys. 677 62