Plasma levels, metabolic clearance rates, and rates of secretion of testosterone and estradiol-l7 beta in the silver eel (Anguilla anguilla L. ) (in French)
Testosterone (T) and 17 beta-estradiol (E2) plasma levels and metabolic clearance rates (MCR) were measured to investigate their ovarian production in immature silver eel. The dynamics of T and E2 metabolism were studied in catheterized eels using single injections of 0.2 to 0.5 microCi /sup 3/H-labeled steroid. The distribution volumes, biological half-life and MCR of nonconjugated tracers were calculated on the basis of a two-compartment model. At the end of the experiments, radioactivity was measured in different organs and tissues to localize the site of T and E2 catabolism. The volume of the inner compartment was 3.4% for T and E2. The outer compartment was larger for T (6.4%) than that for E2 (4.3%). The biological half-life was three to four times shorter for T (14.5 hr) than that for E2 (48.5 hr). The MCR for T (1.71 ml/kg body wt/hr) was higher than for E2 (0.51 ml/kg body wt/hr). Plasma levels were determined, using radioimmunoassay, on samples taken before injections of radiolabeled steroid. Free or protein-bound hormone levels were 0.12 and 0.31 ng/ml for T and E2, respectively. Conjugated T and E2 levels were, respectively, 0.13 and 0.23 ng/ml. Production rates were determined as the product of the MCR and the plasma concentration of the nonconjugated hormone. No significant differences were observed between the production rates of T and E2 (0.24 ng/kg body wt/hr). The liver was the principal site of metabolism for both hormones, which were excreted via the enterohepatic route. E2 injection gave rise to no metabolite in the plasma whereas after T injection a metabolite was produced, the concentration of which increased as a function of time. Its chromatographic properties were different from that of E2 or androstenedione, suggesting that no significant peripheral aromatization or 17-oxidoreduction occurs in the immature silver eel.
- Research Organization:
- Museum national d'Histoire naturelle, Paris, France
- OSTI ID:
- 6170624
- Journal Information:
- Gen. Comp. Endocrinol.; (United States), Vol. 3
- Country of Publication:
- United States
- Language:
- French
Similar Records
The metabolic clearance of progesterone in the pregnant rat: Absence of a physiological role for the lung
Effects of recombinant eel growth hormone on the uptake of ( sup 35 S)sulfate by ceratobranchial cartilages of the Japanese eel, Anguilla japonica
Related Subjects
ESTRADIOL
CLEARANCE
METABOLISM
TESTOSTERONE
BILE
BIOLOGICAL HALF-LIFE
EEL
INTESTINES
LIVER
OVARIES
RADIOIMMUNOASSAY
SECRETION
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ANDROGENS
ANDROSTANES
ANIMALS
AQUATIC ORGANISMS
BIOLOGICAL MATERIALS
BODY
BODY FLUIDS
DIGESTIVE SYSTEM
ESTRANES
ESTROGENS
FEMALE GENITALS
FISHES
GASTROINTESTINAL TRACT
GLANDS
GONADS
HORMONES
HYDROXY COMPOUNDS
IMMUNOLOGY
ISOTOPE APPLICATIONS
KETONES
LABELLED COMPOUNDS
MATERIALS
ORGANIC COMPOUNDS
ORGANS
RADIOASSAY
RADIOIMMUNOLOGY
STEROID HORMONES
STEROIDS
VERTEBRATES
550501* - Metabolism- Tracer Techniques