On the enterohepatic cycle of triiodothyronine in rats; importance of the intestinal microflora

Journal Article · Sun Jan 01 00:00:00 EST 1989 · Life Sciences; (USA)

DOI:https://doi.org/10.1016/0024-3205(89)90179-3· OSTI ID:7066927

de Herder, W W; Hazenberg, M P; Pennock-Schroeder, A M; Oosterlaken, A C; Rutgers, M; Visser, T J ^[1]

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1. Erasmus Univ. Medical School, Rotterdam (Netherlands)

Until 70 h after a single iv injection of 10 uCi ({sup 125}I)triiodothyronine (T{sub 3}), normal rats excreted 15.8 {plus minus} 2.8% of the radioactivity with the feces and 17.5 {plus minus} 2.7% with the urine, while in intestine-decontaminated rats fecal and urinary excretion over this period amounted to 25.1 {plus minus} 7.2% and 23.6 {plus minus} 4.0% of administered radioactivity, respectively (mean {plus minus} SD, n=4). In fecal extracts of decontaminated rats 11.5 {plus minus} 6.8% of the excreted radioactivity consisted of T{sub 3} glucuronide (T{sub 3}G) and 10.9 {plus minus} 2.8% of T{sub 3} sulfate (T{sub 3}S), whereas no conjugates were detected in feces from normal rats. Until 26 h after ig administration of 10 uCi ({sup 125}I)T{sub 3}, integrated radioactivity in blood of decontaminated rats was 1.5 times higher than that in normal rats. However, after ig administration of 10 uCi ({sup 125}I)T{sub 3}G or ({sup 125}I)T{sub 3}S, radioactivity in blood of decontaminated rats was 4.9- and 2.8-fold lower, respectively, than in normal rats. The radioactivity in the serum of control animals was composed of T{sub 3} and iodide in proportions independent of the tracer injected, while T{sub 3} conjugates represented <10 % of serum radioactivity. These results suggest an important role of the intestinal microflora in the enterohepatic circulation of T{sub 3} in rats.

• OSTI ID: 7066927
• Journal Information: Life Sciences; (USA), Vol. 45:9; ISSN 0024-3205
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
MICROORGANISMS
BIOLOGICAL FUNCTIONS
TRIIODOTHYRONINE
METABOLISM
ANTIBIOTICS
EXCRETION
INTESTINAL ABSORPTION
INTESTINES
IODINE 125
LIVER
RATS
TRACER TECHNIQUES
ABSORPTION
ANIMALS
ANTI-INFECTIVE AGENTS
BETA DECAY RADIOISOTOPES
BODY
CLEARANCE
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
FUNCTIONS
GASTROINTESTINAL TRACT
GLANDS
HORMONES
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
MAMMALS
NUCLEI
ODD-EVEN NUCLEI
ORGANS
PEPTIDE HORMONES
RADIOISOTOPES
RODENTS
THYROID HORMONES
UPTAKE
VERTEBRATES
550501* - Metabolism- Tracer Techniques