In:
Acta Endocrinologica, Oxford University Press (OUP), Vol. 104, No. 2 ( 1983-10), p. 134-138
Abstract:
Abstract. Previous studies have shown the existence of specific high affinity T 3 binding sites in rat cerebrocortical synaptosomes. In this study, to define the localization of the binding sites, T 3 binding to disrupted synaptic membrane fractions was compared with the binding to intact synaptosomes obtained from the rat cerebral cortex. Scatchard analysis revealed two orders of T 3 binding sites with almost identical apparent dissociation constant (Kd) in synaptosomes and synaptic membrane fractions. However, the maximal binding capacity (MBC) of the higher affinity binding sites for synaptic membrane fractions was significantly greater than that for intact synaptosomes (4.2 ± 0.2 vs 3.0 ± 0.3 pg T 3 /mg protein). Regional distribution of the synaptosomal T 3 binding sites in various areas of the rat brain was also studied. The Kd values were not significantly different in discrete brain regions. On the other hand, the MBCs of the higher affinity binding sites were greater in the cerebral cortex and hypothalamus (72.8 ± 1.4 and 64.8 ± 9.5 pg T 3 /g tissue) than in the cerebellum (22.1 ± 1.6 pg T 3 /g tissue). Similar difference was also observed in the lower affinity sites. These results indicate that the specific T 3 binding sites in brain synaptosomes are localized mainly on synaptic membranes and that the MBC is different in discrete brain regions.
Type of Medium:
Online Resource
ISSN:
0804-4643
,
1479-683X
DOI:
10.1530/acta.0.1040134
Language:
Unknown
Publisher:
Oxford University Press (OUP)
Publication Date:
1983
detail.hit.zdb_id:
1485160-X
Bookmarklink