Semicomprehensive Analysis of the Postnatal Age-Related Changes in the mRNA Expression of Sex Steroidogenic Enzymes and Sex Steroid Receptors in the Male Rat Hippocampus.

Authors: Kimoto, T  Ishii, H  Higo, S  Hojo, Y  Kawato, S 
Citation: Kimoto T, etal., Endocrinology. 2010 Nov 3.
Pubmed: (View Article at PubMed) PMID:21047951
DOI: Full-text: DOI:10.1210/en.2010-0581

Although sex steroids play a crucial role in the postnatal brain development, the age-related changes in the hippocampal steroidogenesis remain largely unknown. We performed comprehensive investigations for the mRNA expressions of 26 sex steroidogenic enzymes/proteins and three sex steroid receptors in the male rat hippocampus, at the ages of postnatal day (PD) 1, PD4, PD7, PD10, PD14, 4 wk, and 12 wk (adult), by RT-PCR/Southern blotting analysis. The relative expression levels of these enzymes/receptors at PD1 were Srd5a1 > Star > Ar approximately Hsd17b4 approximately Hsd17b1 approximately Hsd17b7 approximately Esr1 approximately Srd5a2 > Hsd17b3 > Esr2 > Cyp11a1 > Cyp17a1 > Cyp19a1 approximately Hsd17b2 > 3beta-hydroxysteroid dehydrogenase I. The mRNA levels of essential enzymes for progesterone/testosterone/estradiol metabolisms (Cyp17a1, Hsd17b7, and Cyp19a1) were approximately constant between PD1 and PD14 and then declined toward the adult levels. Cyp11a1 increased during PD4-PD14 and then considerably decreased toward the adult level ( approximately 8% of PD1). Hsd17b1, Hsd17b2, and 3beta-hydroxysteroid dehydrogenase I mRNA decreased approximately monotonously. Hsd17b3 increased to approximately 200% of PD1 during PD4-PD14 and was maintained at this high level. The 5alpha-reductase mRNA was maintained constant (Srd5a1) or decreased monotonically (Srd5a2) toward the adult level. The Esr1 level peaked at PD4 and decreased toward the adult level, whereas Ar greatly increased during PD1-PD14 and was maintained at this high level. The Star and Hsd17b4 levels were maintained constant from neonate to adult. These results suggest that the hippocampal sex steroidogenic properties are substantially altered during the postnatal development processes, which might contribute to brain sexual maturation.

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CRRD Object Information
CRRD ID: 4145527
Created: 2010-11-09
Species: All species
Last Modified: 2010-11-09
Status: ACTIVE



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RGD is funded by grant HL64541 from the National Heart, Lung, and Blood Institute on behalf of the NIH.