The intermediate lactotroph: A morphologically distinct, ghrelin-responsive pituitary cell in the dwarf (dw/dw) Rat

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dc.contributor.authorHuerta-Ocampo, I.
dc.contributor.authorChristian, H.
dc.contributor.authorThompson, N.
dc.contributor.authorEl-Kasti, M.
dc.contributor.authorWells, T.
dc.date.issued2005
dc.description.abstractProfound 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.
dc.description.statementofresponsibilityIcnelia Huerta-Ocampo, Helen C. Christian, Nichola M. Thompson, Muna M. El-Kasti, and Timothy Wells
dc.identifier.citationEndocrinology, 2005; 146(11):5012-5023
dc.identifier.doi10.1210/en.2005-0335
dc.identifier.issn0013-7227
dc.identifier.issn0013-7227
dc.identifier.orcidThompson, N. [0000-0003-0378-2581]
dc.identifier.urihttp://hdl.handle.net/2440/64695
dc.language.isoen
dc.publisherEndocrine Soc
dc.rightsCopyright © 2005 by The Endocrine Society
dc.source.urihttps://doi.org/10.1210/en.2005-0335
dc.subjectPituitary Gland, Anterior
dc.subjectNeurosecretory Systems
dc.subjectAnimals
dc.subjectMice, Inbred C57BL
dc.subjectMice
dc.subjectRats
dc.subjectRats, Mutant Strains
dc.subjectDwarfism
dc.subjectProlactin
dc.subjectPeptide Hormones
dc.subjectGrowth Hormone
dc.subjectMicroscopy, Electron
dc.subjectAging
dc.subjectPregnancy
dc.subjectFemale
dc.subjectMale
dc.subjectGrowth Hormone-Releasing Hormone
dc.subjectGhrelin
dc.titleThe intermediate lactotroph: A morphologically distinct, ghrelin-responsive pituitary cell in the dwarf (dw/dw) Rat
dc.typeJournal article
pubs.publication-statusPublished

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