Age-related changes in adrenergic alpha 1, alpha 2, and beta receptors of rat white fat cell membranes: an analysis using [3H]bunazosin as a novel ligand for the alpha 1 adrenoceptor.
Age-related changes in alpha 1-, alpha 2-, and beta-catecholamine receptors on membrane of rat epididymal fat cells were investigated. Both young (6 weeks old, weight about 190 g) and aged (20 weeks old, weight about 490 g) Sprague-Dawley male rats were used. For the alpha 1-adrenoceptor binding exp...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
1991-02-01
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| Series: | Journal of Lipid Research |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0022227520420796 |
| _version_ | 1818671888138764288 |
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| author | T Kobatake Y Watanabe Y Matsuzawa K Tokunaga S Fujioka T Kawamoto Y Keno S Tarui H Yoshida |
| author_facet | T Kobatake Y Watanabe Y Matsuzawa K Tokunaga S Fujioka T Kawamoto Y Keno S Tarui H Yoshida |
| author_sort | T Kobatake |
| collection | DOAJ |
| description | Age-related changes in alpha 1-, alpha 2-, and beta-catecholamine receptors on membrane of rat epididymal fat cells were investigated. Both young (6 weeks old, weight about 190 g) and aged (20 weeks old, weight about 490 g) Sprague-Dawley male rats were used. For the alpha 1-adrenoceptor binding experiment, we developed a novel analytical method using the hydrophilic alpha 1-receptor selective antagonist, [3H]bunazosin. The binding of [3H]bunazosin to its binding sites was rapid, reversible, saturable, and stereospecific. Scatchard binding analysis showed a single class of binding site. The sites were characterized as alpha 1-adrenoceptors by inhibition experiments using various agonists and antagonists. The number of maximum binding sites (Bmax) of alpha 1-receptor binding was 37.0 +/- 6.5 (young) versus 24.0 +/- 3.2 (aged) fmol/mg protein (P less than 0.01). [3H]Rauwolscine and [3H]CGP-12177 were used for alpha 2- and beta-receptor binding, respectively. In alpha 2-receptor detection using [3H]rauwolscine as a ligand, Bmax increased markedly from 19.8 +/- 4.9 to 86.2 +/- 19.5 fmol/mg protein (P less than 0.01). In contrast, Bmax for beta-receptor decreased from 69.7 +/- 9.7 to 45.4 +/- 13.9 fmol/mg protein with increasing rat age (P less than 0.05). Kd showed no change in each of the binding experiments between young and aged rats. The cell volume increased from 0.07 +/- 0.02 to 0.15 +/- 0.06 nl. It is implied that anti-lipolytic activity strengthened on the whole mainly with the marked increase of alpha 2-receptor number and decrease of beta-receptor number.(ABSTRACT TRUNCATED AT 250 WORDS) |
| first_indexed | 2024-12-17T07:31:09Z |
| format | Article |
| id | doaj.art-b5524c3705704c59a19aca3069f48d03 |
| institution | Directory Open Access Journal |
| issn | 0022-2275 |
| language | English |
| last_indexed | 2024-12-17T07:31:09Z |
| publishDate | 1991-02-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Lipid Research |
| spelling | doaj.art-b5524c3705704c59a19aca3069f48d032022-12-21T21:58:29ZengElsevierJournal of Lipid Research0022-22751991-02-01322191196Age-related changes in adrenergic alpha 1, alpha 2, and beta receptors of rat white fat cell membranes: an analysis using [3H]bunazosin as a novel ligand for the alpha 1 adrenoceptor.T Kobatake0Y Watanabe1Y Matsuzawa2K Tokunaga3S Fujioka4T Kawamoto5Y Keno6S Tarui7H Yoshida8Second Department of Internal Medicine, Osaka University Medical School, Japan.Second Department of Internal Medicine, Osaka University Medical School, Japan.Second Department of Internal Medicine, Osaka University Medical School, Japan.Second Department of Internal Medicine, Osaka University Medical School, Japan.Second Department of Internal Medicine, Osaka University Medical School, Japan.Second Department of Internal Medicine, Osaka University Medical School, Japan.Second Department of Internal Medicine, Osaka University Medical School, Japan.Second Department of Internal Medicine, Osaka University Medical School, Japan.Second Department of Internal Medicine, Osaka University Medical School, Japan.Age-related changes in alpha 1-, alpha 2-, and beta-catecholamine receptors on membrane of rat epididymal fat cells were investigated. Both young (6 weeks old, weight about 190 g) and aged (20 weeks old, weight about 490 g) Sprague-Dawley male rats were used. For the alpha 1-adrenoceptor binding experiment, we developed a novel analytical method using the hydrophilic alpha 1-receptor selective antagonist, [3H]bunazosin. The binding of [3H]bunazosin to its binding sites was rapid, reversible, saturable, and stereospecific. Scatchard binding analysis showed a single class of binding site. The sites were characterized as alpha 1-adrenoceptors by inhibition experiments using various agonists and antagonists. The number of maximum binding sites (Bmax) of alpha 1-receptor binding was 37.0 +/- 6.5 (young) versus 24.0 +/- 3.2 (aged) fmol/mg protein (P less than 0.01). [3H]Rauwolscine and [3H]CGP-12177 were used for alpha 2- and beta-receptor binding, respectively. In alpha 2-receptor detection using [3H]rauwolscine as a ligand, Bmax increased markedly from 19.8 +/- 4.9 to 86.2 +/- 19.5 fmol/mg protein (P less than 0.01). In contrast, Bmax for beta-receptor decreased from 69.7 +/- 9.7 to 45.4 +/- 13.9 fmol/mg protein with increasing rat age (P less than 0.05). Kd showed no change in each of the binding experiments between young and aged rats. The cell volume increased from 0.07 +/- 0.02 to 0.15 +/- 0.06 nl. It is implied that anti-lipolytic activity strengthened on the whole mainly with the marked increase of alpha 2-receptor number and decrease of beta-receptor number.(ABSTRACT TRUNCATED AT 250 WORDS)http://www.sciencedirect.com/science/article/pii/S0022227520420796 |
| spellingShingle | T Kobatake Y Watanabe Y Matsuzawa K Tokunaga S Fujioka T Kawamoto Y Keno S Tarui H Yoshida Age-related changes in adrenergic alpha 1, alpha 2, and beta receptors of rat white fat cell membranes: an analysis using [3H]bunazosin as a novel ligand for the alpha 1 adrenoceptor. Journal of Lipid Research |
| title | Age-related changes in adrenergic alpha 1, alpha 2, and beta receptors of rat white fat cell membranes: an analysis using [3H]bunazosin as a novel ligand for the alpha 1 adrenoceptor. |
| title_full | Age-related changes in adrenergic alpha 1, alpha 2, and beta receptors of rat white fat cell membranes: an analysis using [3H]bunazosin as a novel ligand for the alpha 1 adrenoceptor. |
| title_fullStr | Age-related changes in adrenergic alpha 1, alpha 2, and beta receptors of rat white fat cell membranes: an analysis using [3H]bunazosin as a novel ligand for the alpha 1 adrenoceptor. |
| title_full_unstemmed | Age-related changes in adrenergic alpha 1, alpha 2, and beta receptors of rat white fat cell membranes: an analysis using [3H]bunazosin as a novel ligand for the alpha 1 adrenoceptor. |
| title_short | Age-related changes in adrenergic alpha 1, alpha 2, and beta receptors of rat white fat cell membranes: an analysis using [3H]bunazosin as a novel ligand for the alpha 1 adrenoceptor. |
| title_sort | age related changes in adrenergic alpha 1 alpha 2 and beta receptors of rat white fat cell membranes an analysis using 3h bunazosin as a novel ligand for the alpha 1 adrenoceptor |
| url | http://www.sciencedirect.com/science/article/pii/S0022227520420796 |
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