Double‐labeling immunogold electron‐microscopic study of hormonal colocalization in nontumorous and adenomatous rat pituitaries

Losinski, Noemi E.; Horváth, Éva; Kovács, Kálmán

doi:10.1002/aja.1001850216

Cited by 32 publications

(11 citation statements)

References 28 publications

(30 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…FOR more than half a century, the "one cell-one hormone" theory was proposed in which each of the major pituitary hormones is produced by a separate and distinct cell type, but immunocytochemical evidence indicates that this theory must be modified since there are some cells containing two hormones, PRL and GH [1,2]. The existence of LH/FSH cells has also been reported [3].…”

mentioning

confidence: 99%

Bihormonal Cells Secreting Both Prolactin and Gonadotropins in Normal Rat Pituitary Cells.

et al. 1997

View full text Add to dashboard Cite

Abstract. The present study was designed to characterize bihormonal cells in rat pituitary cells which secrete PRL and gonadotropins.This was done by using sandwich cell immunoblot assay (CIBA) and reverse hemolytic plaque assay (RHPA) in combination with immunocytochemistry (ICC) and by measuring the intracellular free calcium concentration ([Ca2+];). The result of the experiment with sandwich CIBA revealed that the populations of LH-and FSH-secreting cells in the PRL-secreting cells were 6.23% and 5.91%, respectively, and the populations of the PRL secreting cells in the LH-and FSHsecreting cells were 18.4% and 15.5%, respectively. Additional studies by the combined techniques of RHPA with ICC revealed that the populations of LH-and FSH-containing cells in the PRL secreting cells were 4.43% and 2.40%, respectively, which were consistent with the results of Sandwich CIBA. Some of the PRL-secreting cells determined by RHPA showed responsiveness to TRH and GnRH in [Ca2+];. These results suggest that bihormonal cells which secrete both PRL and LH, or both PRL and FSH are present in the normal rat pituitaries.

show abstract

mentioning

confidence: 99%

Bihormonal Cells Secreting Both Prolactin and Gonadotropins in Normal Rat Pituitary Cells.

et al. 1997

View full text Add to dashboard Cite

show abstract

“…Besides PRL and GH colocalization, pituitary cells have been shown to contain or express more than one hormone such as ACTH and FSH (24), PRL and FSH (25), and GH and LH␤ or FSH␤ mRNA (26). It is thus evident that adult differentiated pituitary cells retain their functional plasticity.…”

Section: Turkey Mammosomatotrophsmentioning

confidence: 99%

Identification of Mammosomatotrophs in the Turkey Hen Pituitary: Increased Abundance during Hyperprolactinemia*

et al. 1998

View full text Add to dashboard Cite

We have previously reported that the hyperprolactinemia in incubating turkey hens is associated with recruitment of lactotrophs in the pituitary gland. In this study we have used double immunofluorescence and in situ hybridization histochemistry to 1) identify mammosomatotrophs in the anterior pituitary gland of egg-laying turkey hens and incubating hens, and 2) verify PRL gene expression within mammosomatotrophs by colocalizing PRL messenger RNA in GHimmunoreactive (ir) cells. The pituitaries of laying and incubating turkey hens were collected, and the midsagittal sections were dual labeled for either PRL and GH or PRL messenger RNA and GH. The plasma PRL concentrations were higher in incubating hens (231 Ϯ 10.6 ng/ml) than in laying hens (43 Ϯ 7.4 ng/ml; P Ͻ 0.01). In the midsagittal pituitary sections, mammosomatotrophs were predominantly found scattered in the caudal lobe of the anterior pituitary gland, in the ventral half of the cephalic lobe, and at the junction of cephalic and caudal lobes. In incubating hens, the proportion of mammosomatotrophs was 7.4 Ϯ 1.52% (mean Ϯ SEM) of the total number of GH-ir and/or PRL-ir cells counted, which was significantly higher (P Ͻ 0.05) than that found in laying hens (0.6 Ϯ 0.23%). Furthermore, PRL gene expression was observed in many GH-ir cells in the incubating hen pituitary gland. These data suggest that 1) mammosomatotrophs are present in the turkey pituitary gland, and 2) there is an increased abundance of mammosomatotrophs in the incubating turkey hen that may contribute to hyperprolactinemia. (Endocrinology 139: [781][782][783][784][785][786] 1998)

show abstract

“…In adult rat pituitary, bi-hormonal thyro-somatotroph cells have been noted [4]. Furthermore, cells with colocalization of GH and TSH are frequent in multihormonal pituitary adenomas [5].…”

Section: Introductionmentioning

confidence: 99%

Somatotroph to thyrotroph cell transdifferentiation during experimental hypothyroidism ‐ a light and electron‐microscopy study

Radian

Coculescu

Morris

2003

J Cellular Molecular Medi

View full text Add to dashboard Cite

Somatotroph and thyrotroph pituitary cells share a common precursor cell expressing the transcription factor Pit1 in ontogeny. Cells expressing both thyrotropin (TSH) and growth-hormone (GH) are found in adult rat pituitary and in human pituitary adenomas in acromegaly, and these tumors contain both thyrotropin-releasing hormone (TRH) and the TRH receptors (TRHR). It has been shown that stimulation of TSH expression in primary hypothyroidism promotes changes suggestive of somatotroph to thyrotroph cell transdifferentiation. We tested this hypothesis and the role of TRH in experimental primary hypothyroidism in rats. Adult female Long-Evans rats, 6 months old, were administered the antithyroid drug methimazole (0,1% w/v) in the drinking water for 42 days. Animals were sacrificed by perfusion fixation under anaesthesia at weekly intervals and pituitary tissue processed in acrylic resin for immunofluorescence and immuno-electronmicroscopy for TSH, GH and TRHR. In the hypothyroid rat pituitary immunofluorescent somatotrophs were greatly reduced in number and gradually replaced by thyrotrophs during methimazole administration. Colocalization of GH and TSH in the same cell was noted. Immunoelectronmicroscopy demonstrated the development of enlarged thyrotrophs with dilated rough endoplasmic reticulum containing an electron-dense material and intracisternal granules, both of which are immunoreactive for TSH ('thyroidectomy cells'). The somatotrophs showed reduced GH immunoreactivity and also the presence of TSH-type, small-size secretory granules. This suggests that the greatly increased number of TSH-cells in methimazole-induced-hypothyroidism is due, at least partially, to the transdifferentiation of somatotroph into thyrotroph cells. TRHR immunofluorescence was expressed in many somatotrophs in normal rat pituitary and unlike immunoreactive GH, its expression was enhanced during hypothyroidism. The number of TRHR-immunoreactive cells increased in parallel with the number of TSH-immunoreactive cells. This indicates a role for TRH stimulation in the transdifferentiation process. Taken together, these data suggest that, in addition to the cell mutation mechanism involving an early totipotential progenitor cell, transdifferentiation of existing somatotroph cells also plays a part in the pathogenesis of multihormonal GH-secreting adenomas.

show abstract

Double‐labeling immunogold electron‐microscopic study of hormonal colocalization in nontumorous and adenomatous rat pituitaries

Cited by 32 publications

References 28 publications

Bihormonal Cells Secreting Both Prolactin and Gonadotropins in Normal Rat Pituitary Cells.

Bihormonal Cells Secreting Both Prolactin and Gonadotropins in Normal Rat Pituitary Cells.

Identification of Mammosomatotrophs in the Turkey Hen Pituitary: Increased Abundance during Hyperprolactinemia*

Somatotroph to thyrotroph cell transdifferentiation during experimental hypothyroidism ‐ a light and electron‐microscopy study

Contact Info

Product

Resources

About