High affinity amylin binding sites in rat brain
Amylin, a 37-amino acid peptide structurally related to calcitonin gene-related peptide, is synthesized in and released along with insulin from pancreatic beta-cells. Amylin is proposed to act as an endocrine partner to insulin, in part through actions upon skeletal muscle that promote cycling of gl...
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Veröffentlicht in: | Molecular pharmacology 1993-09, Vol.44 (3), p.493-497 |
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Zusammenfassung: | Amylin, a 37-amino acid peptide structurally related to calcitonin gene-related peptide, is synthesized in and released along
with insulin from pancreatic beta-cells. Amylin is proposed to act as an endocrine partner to insulin, in part through actions
upon skeletal muscle that promote cycling of gluconeogenic precursors to liver. We report here that binding sites with high
affinity (Kd = 27 pm) for radioiodinated rat amylin are present in the nucleus accumbens region of rat brain. Competition
experiments show that sites measured in nucleus accumbens membranes have high affinity for rat amylin, lower affinity for
rat calcitonin gene-related peptides, and very low affinity for rat calcitonin. In contrast to rat calcitonin, salmon calcitonin
has a high affinity for these sites, indicating that it shares critical binding determinants with amylin. We further tested
whether salmon calcitonin shares with amylin the ability to regulate glycogen metabolism in rat skeletal muscle. Salmon calcitonin
potently inhibits insulin-stimulated glucose incorporation into rat soleus muscle glycogen, suggesting that rat skeletal muscle
may also contain receptor populations that have high affinity for both amylin and salmon calcitonin. |
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ISSN: | 0026-895X 1521-0111 |