title: Mode of GH administration and gene expression in the female rat brain.
abstract: The endogenous secretion of growth hormone (GH) is sexually dimorphic in rats with females having a more even and males a more pulsatile secretion and low trough levels. The mode of GH administration, mimicking the sexually dimorphic secretion, has different systemic effects. In the brains of male rats, we have previously found that the mode of GH administration differently affects neuron-haemoglobin beta (Hbb) expression whereas effects on other transcripts were moderate. The different modes of GH administration could have different effects on brain transcripts in female rats. Hypophysectomised female rats were given GH either as injections twice daily or as continuous infusion and GH-responsive transcripts were assessed by quantitative reverse transcription polymerase chain reaction in the hippocampus and parietal cortex (cortex). The different modes of GH-administration markedly increasedHbband 5'-aminolevulinate synthase 2 (Alas2) in both brain regions. As other effects were relatively moderate, a mixed model analysis (MMA) was used to investigate general effects of the treatments. In the hippocampus, MMA showed that GH-infusion suppressed glia- and neuron-related transcript expression levels, whereas GH-injections increased expression levels. In the cortex, GH-infusion instead increased neuron-related transcripts, whereas GH-injections had no significant effect. Interestingly, this contrasts to previous results obtained from male rat cortex where GH-infusion generally decreased expression levels. In conclusion, the results indicate that there is a small but significant difference in response to mode of GH administration in the hippocampus as compared to the cortex. For both modes of GH administration, there was a robust effect onHbbandAlas2.
authors.affiliation: Department of Internal MedicineInstitute of Medicine, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden marion.walser@medic.gu.se.
authors.forename: Marion
authors.initials: M
authors.lastname: Walser
authors.affiliation: Department for Public Health and Community MedicineThe Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
authors.forename: Linus
authors.initials: L
authors.lastname: Schiöler
authors.affiliation: AstraZeneca GothenburgMölndal, Sweden.
authors.forename: Jan
authors.initials: J
authors.lastname: Oscarsson
authors.affiliation: Department of Primary Health CareInstitute of Medicine, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
authors.forename: Maria A I
authors.initials: MA
authors.lastname: Åberg
authors.affiliation: Department of Clinical Chemistry and Transfusion MedicineThe Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
authors.forename: Ruth
authors.initials: R
authors.lastname: Wickelgren
authors.affiliation: Department of Internal MedicineInstitute of Medicine, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Svensson
authors.affiliation: Department of Internal MedicineInstitute of Medicine, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
authors.forename: Jörgen
authors.initials: J
authors.lastname: Isgaard
authors.affiliation: Department of Internal MedicineInstitute of Medicine, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
authors.forename: N David
authors.initials: ND
authors.lastname: Åberg
mesh_terms: D000624:5-Aminolevulinate Synthetase / Q000235:genetics / Q000378:metabolism; D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology*; D013006:Growth Hormone / Q000008:administration & dosage* / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D006624:Hippocampus / Q000378:metabolism; D007016:Hypophysectomy; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D013006:Growth Hormone; D000624:5-Aminolevulinate Synthetase
keywords: female; gene transcription; growth hormone; infusion pumps; injections