Ultrastructural immunolocalization of IGF-1 and insulin receptors in rat pituitary culture: evidence of a functional interaction between gonadotroph and lactotroph cells
| Autor: | Agustín Aoki, Silvina Gutiérrez, Alicia Inés Torres, Jorge Humberto Mukdsi, Elsa Margarita Orgnero, Alejandro Peralta Soler |
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| Rok vydání: | 2006 |
| Předmět: |
endocrine system
medicine.medical_specialty Histology Lactotrophs medicine.medical_treatment Cell Count Gonadotrophs Gonadotropic cell Receptor IGF Type 1 Pathology and Forensic Medicine Immunoenzyme Techniques Prolactin cell Microscopy Electron Transmission Pituitary Gland Anterior Internal medicine medicine Animals Insulin Insulin-Like Growth Factor I Rats Wistar Receptor Cells Cultured Cell Proliferation Insulin-like growth factor 1 receptor Dose-Response Relationship Drug biology Growth factor DNA Cell Biology Receptor Insulin Prolactin Rats Drug Combinations Insulin receptor Endocrinology Fluorescent Antibody Technique Direct biology.protein Female |
| Zdroj: | Cell and Tissue Research. 327:121-132 |
| ISSN: | 1432-0878 0302-766X |
| DOI: | 10.1007/s00441-006-0283-4 |
| Popis: | We have investigated the expression of receptors for insulin and insulin-like growth factor 1 (IGF-1) in rat pituitary cells in vitro and examined the morphological and proliferative changes induced in adenohypophyseal cells by insulin and IGF-1. The proliferation of lactotrophs was determined by double-immunostaining for bromodeoxyuridine and prolactin. Incubation with insulin (10, 100 or 1000 ng/ml) or IGF-1 (5, 30 or 100 ng/ml) for 48 or 72 h significantly increased the number of lactotrophs undergoing mitosis. Co-incubation of insulin or IGF-1 with genistein (25 microM), an inhibitor of the tyrosine kinase receptor, reduced the proliferation of lactotrophs elicited by the hormone and the growth factor. The receptors for insulin and IGF-1 were localized in intact pituitary cells by ultrastructural immunocytochemistry with the colloidal gold-protein A technique. Gonadotrophs expressed both receptors, specific labelling being restricted to this cell type. Electron-microscopical observations of pituitary cell cultures incubated with insulin or IGF-1 revealed gonadotroph cells exhibiting the fine-structural features of enhanced protein synthetic activity. These findings suggest that both insulin and IGF-1 are able to induce the proliferation of lactotrophs through an indirect mechanism mediated by a factor synthesized by gonadotroph cells, in addition to stimulating the biosynthetic activity of the gonadotroph in a direct manner. |
| Databáze: | OpenAIRE |
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