Peripheral administration of GH induces cell proliferation in the brain of adult hypophysectomized rats.
IGF-I treatment has been shown to enhance cell genesis in the brains of adult GH- and IGF-I-deficient rodents; however, the influence of GH therapy remains poorly understood. The present study investigated the effects of peripheral recombinant bovine GH (bGH) on cellular proliferation and survival in the neurogenic regions (subventricular zone (SVZ), and dentate gyrus of the hippocampus), as well as the corpus callosum, striatum, parietal cortex, and piriform cortex. Hypopituitarism was induced in female rats by hypophysectomy, and the rats were supplemented with thyroxine and cortisone acetate. Subsequently, the rats received daily s.c. injections of bGH for either 6 or 28 days respectively. Following 5 days of peripheral bGH administration, the number of bromodeoxyuridine (BrdU)-positive cells was increased in the hippocampus, striatum, parietal cortex, and piriform cortex after 6 and 28 days. In the SVZ, however, BrdU-positive cells increased only after 28 days of bGH treatment. No significant change was observed in the corpus callosum. In the hippocampus, after 28 days of bGH treatment, the number of BrdU/NeuN-positive cells was increased proportionally to increase the number of BrdU-positive cells. (3)H-thymidine incorporation in vitro revealed that 24 h of bGH exposure was sufficient to increase cell proliferation in adult hippocampal progenitor cells. This study shows for the first time that 1) peripheral bGH treatment increased the number of newborn cells in the adult brain and 2) bGH exerted a direct proliferative effect on neuronal progenitor cells in vitro.
Aberg
N David
ND
Center of Brain Research and Rehabilitation, Institute of Physiology and Neuroscience, University of Gothenburg, Gothenburg, Sweden.
Johansson
Inger
I
Aberg
Maria A I
MA
Lind
Johan
J
Johansson
Ulf E
UE
Cooper-Kuhn
Christiana M
CM
Kuhn
H Georg
HG
Isgaard
Jörgen
J
D000279:Administration, Cutaneous; D000367:Age Factors; D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000502:physiology; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D005260:Female; D013006:Growth Hormone / Q000008:administration & dosage* / Q000494:pharmacology; D007016:Hypophysectomy; D008954:Models, Biological; D055495:Neurogenesis / Q000187:drug effects; D051381:Rats; D011916:Rats, Inbred F344; D013234:Stem Cells / Q000187:drug effects / Q000502:physiology
D013006:Growth Hormone