RT Journal Article SR Electronic T1 Sex differences and thyroid hormone sensitivity of hippocampal pyramidal cells JF The Journal of Neuroscience JO J. Neurosci. FD Society for Neuroscience SP 996 OP 1003 DO 10.1523/JNEUROSCI.10-03-00996.1990 VO 10 IS 3 A1 Gould, E A1 Westlind-Danielsson, A A1 Frankfurt, M A1 McEwen, BS YR 1990 UL http://www.jneurosci.org/content/10/3/996.abstract AB In an effort to determine if sex differences exist in the morphologic characteristics of pyramidal cells and granule cells of the hippocampal formation and whether sex plays a role in determining thyroid hormone sensitivity of these neuronal populations, we used single-section Golgi impregnation to examine the effects of neonatal thyroid hormone administration on hippocampal cells from the brains of adult rats of both sexes. Quantitative analyses of control brains revealed sex differences in the number of primary dendrites and the number of spines on the apical dendritic shaft of CA3 pyramidal cells. These differences showed opposite trends; females possessed more primary dendrites, whereas males showed more apical excrescences. Neonatal treatment with thyroid hormone resulted in long-lasting and dramatic changes of the entire CA3 pyramidal cell. CA3 pyramidal cells from thyroid hormone- treated animals showed significantly larger cell body areas, greater numbers of dendritic branchpoints, and longer dendrites. In addition, CA3 pyramidal cells from thyroid hormone-treated animals showed changes in the morphological characteristics which were shown to be sexually dimorphic; treatment resulted in significantly greater numbers of both primary dendrites and apical excrescences. These treatment differences occurred in both sexes and were of equal magnitude, regardless of sex. On the other hand, no sex differences in the morphologic parameters examined were detected for pyramidal cells in the CA1 region. Moreover, neonatal thyroid hormone treatment did not affect the cell body area, dendritic branch points, or the length of dendrites of these cells.(ABSTRACT TRUNCATED AT 250 WORDS)