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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
Statement of
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
Mice, Inbred C57BL
Rats, Mutant Strains
Peptide Hormones
Growth Hormone
Microscopy, Electron
Growth Hormone-Releasing Hormone
Rights: Copyright © 2005 by The Endocrine Society
DOI: 10.1210/en.2005-0335
Appears in Collections:Aurora harvest
Medical Sciences publications

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