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Ultrastructural immunolocalization of IGF-1 and insulin receptors in rat pituitary culture: evidence of a functional interaction between gonadotroph and lactotroph cells
- Source :
- Cell and Tissue Research. 327:121-132
- Publication Year :
- 2006
- Publisher :
- Springer Science and Business Media LLC, 2006.
-
Abstract
- 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.
- Subjects :
- 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
Subjects
Details
- ISSN :
- 14320878 and 0302766X
- Volume :
- 327
- Database :
- OpenAIRE
- Journal :
- Cell and Tissue Research
- Accession number :
- edsair.doi.dedup.....fcacb1804eb57980c965fc4596eccb5b
- Full Text :
- https://doi.org/10.1007/s00441-006-0283-4