Measurement of aromatase activity in the brain of the African catfish, Clarias gariepinus—A comparison of two assay methods
| Autor: | J.G.D. Lambert, R.J.M. Timmers |
|---|---|
| Rok vydání: | 1987 |
| Předmět: |
Male
Clarias gariepinus medicine.medical_specialty Physiology medicine.drug_class Tritium Biochemistry Substrate Specificity Aromatase Internal medicine medicine Animals Androstenedione Molecular Biology Incubation Catfishes chemistry.chemical_classification biology Brain Substrate (chemistry) Estrogens General Medicine biology.organism_classification Kinetics Endocrinology Enzyme chemistry Estrogen biology.protein Catfish |
| Zdroj: | Comparative Biochemistry and Physiology Part B: Comparative Biochemistry. 88:453-456 |
| ISSN: | 0305-0491 |
| DOI: | 10.1016/0305-0491(87)90325-7 |
| Popis: | 1. 1. In the brain of the African catfish aromatase activity was demonstrated with two different methods using [7 −3 H]androstenedione and [19 −3 H]androstenedione as substrates. 2. 2. Kinetic analysis of estrogen formation following incubations of a cell-free fraction of brain homogenates showed that the apparent K m is the same for both substrates (0.03 μM), but the V max is smaller with [19 −3 H]androstenedione as substrate. This indicates a so-called isotope effect. 3. 3. A time course study showed that after an incubation of 4 hr the aromatase activity is still linearly time dependent. Comparing the amount of estrogens formed from both precursors showed that the value of the isotope effect is 3.4. 4. 4. Incubation of symmetric punches of telencephalon and diencephalon with the two substrates likewise showed an isotope effect of 3.4. |
| Databáze: | OpenAIRE |
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