Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9434392 | Neuroscience Research | 2005 | 9 Pages |
Abstract
It has previously been suggested that exogenous growth hormone (GH) affect quality of life and higher brain functions through the endogenous opioid system. Recently, we showed that GH down-regulate 72 and 48Â kDa delta opioid receptor (DOR) proteins in the adult rat cerebral cortex and cerebellum. In the present study, we found that an antiserum raised against the N-terminus of the DOR also recognizes a 36Â kDa protein, not recognized by a C-terminus-directed antiserum. We aimed to investigate the identity of the 72, 48 and 36Â kDa proteins and to further study the effects of GH on their expression in different brain regions. The expression was studied in hypophysectomized (Hx) and untreated normal female rats. One subgroup of Hx rats received GH as a daily subcutaneous injection for 19 days. Our data show that treatment with GH in Hx rats normalized the expression of the 72Â kDa protein in the cerebral cortex, whereas no significant effect were observed for the 48 or 36Â kDa proteins. However, GH significantly reduced the ratio between the 72 and 36Â kDa proteins in different brain regions of Hx rats. Our data suggest that GH reduces the levels of a 72Â kDa DOR that likely represents a dimeric form of a 36Â kDa DOR post-translationally truncated at the C-terminus, and that altered receptor dimerization may be involved in GH induced effects in the central nervous system.
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Authors
Anders I. Persson, Thorleif Thorlin, Peter S. Eriksson,