The Intermediate lactotroph: a morphologically distinct, ghrelin-responsive pituitary cell in the dwarf (dw/dw) rat.
Profound somatotroph hypoplasia in the dwarf (dw/dw) rat is accompanied by an estrogen-dependent induction of prolactin secretion by the GH secretagogue, GHRP-6. Using electron microscopy, we demonstrated that the reduction in the somatotroph population in the dw/dw pituitary is accompanied by the p...
| Main Authors: | , , , , |
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| Format: | Journal article |
| Language: | English |
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2005
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| _version_ | 1797103956643545088 |
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| author | Huerta-Ocampo, I Christian, H Thompson, N El-Kasti, M Wells, T |
| author_facet | Huerta-Ocampo, I Christian, H Thompson, N El-Kasti, M Wells, T |
| author_sort | Huerta-Ocampo, I |
| collection | OXFORD |
| description | Profound somatotroph hypoplasia in the dwarf (dw/dw) rat is accompanied by an estrogen-dependent induction of prolactin secretion by the GH secretagogue, GHRP-6. Using electron microscopy, we demonstrated that the reduction in the somatotroph population in the dw/dw pituitary is accompanied by the presence of a morphologically distinct lactotroph subpopulation. In these cells, which did not coexpress GH, the size, shape, and number of the secretory granules were between those of the type I and type II lactotrophs. We therefore called these cells intermediate lactotrophs. The intermediate lactotrophs accounted for up to 30% of the total prolactin-positive cell population in dw/dw males and up to 12% in females. Using tannic acid to quantify the fusion of secretory granules, we have shown that the intermediate lactotrophs are unresponsive to either GH-releasing factor (GRF) or TRH but exhibit a sexually dimorphic secretory response to acute ghrelin treatment, granular fusions being 4-fold higher in females. No cell matching the morphology of the novel lactotroph subpopulation was observed in the pituitary of the GRF-insensitive lit/lit mouse. However, ablation of GRF neurons with neonatal monosodium glutamate treatment had no effect on the population of intermediate lactotrophs in the dw/dw rat. Thus, the presence of the intermediate lactotrophs in the dw/dw pituitary appears to be independent of the function of the GRF neurons. |
| first_indexed | 2024-03-07T06:27:25Z |
| format | Journal article |
| id | oxford-uuid:f4ca9f04-d9c3-434a-9787-a97c0855d980 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T06:27:25Z |
| publishDate | 2005 |
| record_format | dspace |
| spelling | oxford-uuid:f4ca9f04-d9c3-434a-9787-a97c0855d9802022-03-27T12:22:26ZThe Intermediate lactotroph: a morphologically distinct, ghrelin-responsive pituitary cell in the dwarf (dw/dw) rat.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:f4ca9f04-d9c3-434a-9787-a97c0855d980EnglishSymplectic Elements at Oxford2005Huerta-Ocampo, IChristian, HThompson, NEl-Kasti, MWells, TProfound somatotroph hypoplasia in the dwarf (dw/dw) rat is accompanied by an estrogen-dependent induction of prolactin secretion by the GH secretagogue, GHRP-6. Using electron microscopy, we demonstrated that the reduction in the somatotroph population in the dw/dw pituitary is accompanied by the presence of a morphologically distinct lactotroph subpopulation. In these cells, which did not coexpress GH, the size, shape, and number of the secretory granules were between those of the type I and type II lactotrophs. We therefore called these cells intermediate lactotrophs. The intermediate lactotrophs accounted for up to 30% of the total prolactin-positive cell population in dw/dw males and up to 12% in females. Using tannic acid to quantify the fusion of secretory granules, we have shown that the intermediate lactotrophs are unresponsive to either GH-releasing factor (GRF) or TRH but exhibit a sexually dimorphic secretory response to acute ghrelin treatment, granular fusions being 4-fold higher in females. No cell matching the morphology of the novel lactotroph subpopulation was observed in the pituitary of the GRF-insensitive lit/lit mouse. However, ablation of GRF neurons with neonatal monosodium glutamate treatment had no effect on the population of intermediate lactotrophs in the dw/dw rat. Thus, the presence of the intermediate lactotrophs in the dw/dw pituitary appears to be independent of the function of the GRF neurons. |
| spellingShingle | Huerta-Ocampo, I Christian, H Thompson, N El-Kasti, M Wells, T The Intermediate lactotroph: a morphologically distinct, ghrelin-responsive pituitary cell in the dwarf (dw/dw) rat. |
| title | The Intermediate lactotroph: a morphologically distinct, ghrelin-responsive pituitary cell in the dwarf (dw/dw) rat. |
| title_full | The Intermediate lactotroph: a morphologically distinct, ghrelin-responsive pituitary cell in the dwarf (dw/dw) rat. |
| title_fullStr | The Intermediate lactotroph: a morphologically distinct, ghrelin-responsive pituitary cell in the dwarf (dw/dw) rat. |
| title_full_unstemmed | The Intermediate lactotroph: a morphologically distinct, ghrelin-responsive pituitary cell in the dwarf (dw/dw) rat. |
| title_short | The Intermediate lactotroph: a morphologically distinct, ghrelin-responsive pituitary cell in the dwarf (dw/dw) rat. |
| title_sort | intermediate lactotroph a morphologically distinct ghrelin responsive pituitary cell in the dwarf dw dw rat |
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