title: Effect of Testosterone on Neuronal Morphology and Neuritic Growth of Fetal Lamb Hypothalamus-Preoptic Area and Cerebral Cortex in Primary Culture.
abstract: Testosterone plays an essential role in sexual differentiation of the male sheep brain. The ovine sexually dimorphic nucleus (oSDN), is 2 to 3 times larger in males than in females, and this sex difference is under the control of testosterone. The effect of testosterone on oSDN volume may result from enhanced expansion of soma areas and/or dendritic fields. To test this hypothesis, cells derived from the hypothalamus-preoptic area (HPOA) and cerebral cortex (CTX) of lamb fetuses were grown in primary culture to examine the direct morphological effects of testosterone on these cellular components. We found that within two days of plating, neurons derived from both the HPOA and CTX extend neuritic processes and express androgen receptors and aromatase immunoreactivity. Both treated and control neurites continue to grow and branch with increasing time in culture. Treatment with testosterone (10 nM) for 3 days significantly (P < 0.05) increased both total neurite outgrowth (35%) and soma size (8%) in the HPOA and outgrowth (21%) and number of branch points (33%) in the CTX. These findings indicate that testosterone-induced somal enlargement and neurite outgrowth in fetal lamb neurons may contribute to the development of a fully masculine sheep brain.
authors.affiliation: Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon, United States of America.
authors.forename: Radhika C
authors.initials: RC
authors.lastname: Reddy
authors.affiliation: Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon, United States of America.
authors.forename: Rebecka
authors.initials: R
authors.lastname: Amodei
authors.affiliation: Department of Animal and Rangeland Sciences, Oregon State University, Corvallis, Oregon, United States of America; Department of Clinical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, Oregon, United States of America.
authors.forename: Charles T
authors.initials: CT
authors.lastname: Estill
authors.affiliation: Department of Animal and Rangeland Sciences, Oregon State University, Corvallis, Oregon, United States of America.
authors.forename: Fred
authors.initials: F
authors.lastname: Stormshak
authors.affiliation: Department of Animal and Rangeland Sciences, Oregon State University, Corvallis, Oregon, United States of America.
authors.forename: Mary
authors.initials: M
authors.lastname: Meaker
authors.affiliation: Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon, United States of America.
authors.forename: Charles E
authors.initials: CE
authors.lastname: Roselli
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D048430:Cell Shape / Q000187:drug effects*; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000187:drug effects / Q000196:embryology*; D005260:Female; D005333:Fetus / Q000187:drug effects / Q000378:metabolism*; D007150:Immunohistochemistry; D008297:Male; D016501:Neurites / Q000187:drug effects / Q000378:metabolism*; D011301:Preoptic Area / Q000187:drug effects / Q000196:embryology*; D012756:Sheep / Q000196:embryology*; D013739:Testosterone / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D013739:Testosterone