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Characterization of growth hormone binding sites in rat brain
Author(s) -
Zhai Q,
Lai Z,
Roos P,
Nyberg F
Publication year - 1994
Publication title -
acta pædiatrica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 115
eISSN - 1651-2227
pISSN - 0803-5253
DOI - 10.1111/j.1651-2227.1994.tb13433.x
Subject(s) - medicine , growth hormone , hormone , endocrinology
The binding of 125 I‐labelled rat growth hormone (GH) to different areas in the brain was studied in male Sprague‐Dawley rats. A high density of GH binding was found in the choroid plexus, hypothalamus, hippocampus, pituitary and spinal cord, whereas a lower binding density was observed in the cortex. Binding of the hormone to the various brain regions was age dependent. Binding was also dependent on time, pH and protein concentration. The binding affinity of the labelled hormone to choroid plexus was 4.3 per nmol/l and the binding capacity was 33.4 nmol/mg protein. The corresponding figures for binding of 125 I‐labelled GH to hypothalamus were 5.6 per nmol/1 and 21.6 nmol/mg protein. By sodium dodecyl sulphate electrophoresis of the cross‐linked hormone‐receptor complexes, molecular weights of 60,000 and 61,000 were determined for the binding units in the choroid plexus and hypothalamus, respectively. It was further indicated that the binding unit for rat GH was distinct from that for prolactin.