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https://hdl.handle.net/2440/64695
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Type: | Journal article |
Title: | The intermediate lactotroph: A morphologically distinct, ghrelin-responsive pituitary cell in the dwarf (dw/dw) Rat |
Author: | Huerta-Ocampo, I. Christian, H. Thompson, N. El-Kasti, M. Wells, T. |
Citation: | Endocrinology, 2005; 146(11):5012-5023 |
Publisher: | Endocrine Soc |
Issue Date: | 2005 |
ISSN: | 0013-7227 0013-7227 |
Statement of Responsibility: | Icnelia Huerta-Ocampo, Helen C. Christian, Nichola M. Thompson, Muna M. El-Kasti, and Timothy Wells |
Abstract: | 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. |
Keywords: | Pituitary Gland, Anterior Neurosecretory Systems Animals Mice, Inbred C57BL Mice Rats Rats, Mutant Strains Dwarfism Prolactin Peptide Hormones Growth Hormone Microscopy, Electron Aging Pregnancy Female Male Growth Hormone-Releasing Hormone Ghrelin |
Rights: | Copyright © 2005 by The Endocrine Society |
DOI: | 10.1210/en.2005-0335 |
Published version: | http://dx.doi.org/10.1210/en.2005-0335 |
Appears in Collections: | Aurora harvest Medical Sciences publications |
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