title: Sex differences and laterality of insulin receptor distribution in developing rat hippocampus: an immunohistochemical study.
abstract: This study aimed to compare the regional distribution of insulin receptor in various portions of newborn rat hippocampus on postnatal days 0 (P0), 7 (P7), and 14 (P14) between male/female and right/left hippocampi. We found that the number of insulin receptor (InsR)-immunoreactive-positive (InsR+) cells in CA1 continued to increase until P7 and remained unchanged thereafter. A marked increase in distribution of InsR+ cells in CA3 from P0 to P14 was observed, although there was a significant decline in the number of InsR+ cells in dentate gyrus (DG) at the same time. No differences between the right/left and male/female hippocampi were detected at P0 (P > 0.05). Seven-day-old female rats showed a higher number of labeled cells in the left than in the right hippocampus. Moreover, the differences between the number of InsR+ cells in area CA1 and CA3 were statistically significant between males and females (P < 0.05). At P14, the number of InsR+ cells was significantly higher in CA1 and DG of males, especially in the right one (P < 0.05). These results indicate the existence of a differential distribution pattern of InsR between the left/right and male/female hippocampi. Together with other mechanisms, these differences may underlie sexual dimorphism and left/right asymmetry in the hippocampus.
authors.affiliation: Department of Anatomical Sciences, School of Medicine, Birjand University of Medical Sciences, Birjand, Iran.
authors.forename: Javad
authors.initials: J
authors.lastname: Hami
authors.forename: Hamed
authors.initials: H
authors.lastname: Kheradmand
authors.forename: Hossein
authors.initials: H
authors.lastname: Haghir
mesh_terms: D000818:Animals; D005260:Female; D007839:Functional Laterality; D018507:Gene Expression Regulation, Developmental; D006624:Hippocampus / Q000254:growth & development / Q000378:metabolism*; D008297:Male; D009928:Organ Specificity; D051381:Rats; D017208:Rats, Wistar; D011972:Receptor, Insulin / Q000235:genetics / Q000378:metabolism*; D012727:Sex Characteristics
chemical_list: D011972:Receptor, Insulin