In vivo correlation between c-Fos expression and corticotroph stimulation by adrenocorticotrophic hormone secretagogues in rat anterior pituitary gland

The concept of "stimulus-secretion coupling" suggested by Douglas and co-workers to explain the events related to monamine discharge by the adrenal medulla (5, 7) may be applied to other endocrine tissues, such as adrenal cortex (36), pancreatic islets (4), and magnocellular hypothalamic neurons (6), which exhibit a similar ion-dependent process of hormone elaboration. In addition, they share another feature, that of joining neighbor cells via membrane junctions (12, 26, and Fletcher, unpublished observation). Given this, and the reports that hormone secretion by the pars distalis also involves a secretagogue-induced decrease in membrane bioelectric potential accompanied by a rise in cellular [Ca++] (27, 34, 41), it was appropriate to test the possibility that cells of the anterior pituitary gland are united by junctions.

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Bovine Posterior Pituitary Extract Stimulates Prolactin Release from the Anterior Pituitary Gland In Vitro and In Vivo in Cattle

Reproduction in Domestic Animals ◽

10.1111/j.1439-0531.2005.00580.x ◽

2005 ◽

Vol 40 (2) ◽

pp. 184-189 ◽

Cited By ~ 16

Author(s):

T Hashizume ◽

T Sasaki ◽

S Nonaka ◽

T Hayashi ◽

M Takisawa ◽

...

Keyword(s):

Pituitary Gland ◽

Anterior Pituitary ◽

Anterior Pituitary Gland ◽

Posterior Pituitary ◽

Pituitary Extract ◽

Prolactin Release

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In Vivo and In Vitro Arsenic Exposition Induces Oxidative Stress in Anterior Pituitary Gland

International Journal of Toxicology ◽

10.1177/1091581816645797 ◽

2016 ◽

Vol 35 (4) ◽

pp. 463-475 ◽

Cited By ~ 8

Author(s):

Sonia A. Ronchetti ◽

María S. Bianchi ◽

Beatriz H. Duvilanski ◽

Jimena P. Cabilla

Keyword(s):

Oxidative Stress ◽

Pituitary Gland ◽

Anterior Pituitary ◽

Inorganic Arsenic ◽

Anterior Pituitary Gland ◽

Pituitary Cells ◽

Prolactin Release ◽

Stress Responsive Genes

Inorganic arsenic (iAs) is at the top of toxic metalloids. Inorganic arsenic-contaminated water consumption is one of the greatest environmental health threats worldwide. Human iAs exposure has been associated with cancers of several organs, neurological disorders, and reproductive problems. Nevertheless, there are no reports describing how iAs affects the anterior pituitary gland. The aim of this study was to investigate the mechanisms involved in iAs-mediated anterior pituitary toxicity both in vivo and in vitro. We showed that iAs administration (from 5 to 100 ppm) to male rats through drinking water increased messenger RNA expression of several oxidative stress-responsive genes in the anterior pituitary gland. Serum prolactin levels diminished, whereas luteinizing hormone (LH) levels were only affected at the higher dose tested. In anterior pituitary cells in culture, 25 µmol/L iAs significantly decreased prolactin release in a time-dependent fashion, whereas LH levels remained unaltered. Cell viability was significantly reduced mainly by apoptosis evidenced by morphological and phosphatidylserine externalization studies. This process is characterized by early depolarization of mitochondrial membrane potential and increased levels of reactive oxygen species. Expression of some key oxidative stress-responsive genes, such as heme oxygenase-1 and metallothionein-1, was also stimulated by iAs exposure. The antioxidant N-acetyl cysteine prevented iAs-induced effects on the expression of oxidative stress markers, prolactin release, and apoptosis. In summary, the present work demonstrates for the first time that iAs reduces prolactin release both in vivo and in vitro and induces apoptosis in anterior pituitary cells, possibly resulting from imbalanced cellular redox status.

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Gonadotrope Plasticity at Cellular and Population Levels

Endocrinology ◽

10.1210/en.2012-1360 ◽

2012 ◽

Vol 153 (10) ◽

pp. 4729-4739 ◽

Cited By ~ 24

Author(s):

Zahara Alim ◽

Cheryl Hartshorn ◽

Oliver Mai ◽

Iain Stitt ◽

Colin Clay ◽

...

Keyword(s):

Pituitary Gland ◽

Anterior Pituitary ◽

Ex Vivo ◽

Single Cells ◽

Anterior Pituitary Gland ◽

Female Mice ◽

Model Animal ◽

Pituitary Glands ◽

Acute Changes

Abstract Hormone-secreting cells within the anterior pituitary gland may form organized and interdigitated networks that adapt to changing endocrine conditions in different physiological contexts. For gonadotropes, this might reflect a strategy to cope with acute changes throughout different female reproductive stages. The current study examined gonadotropes in female mice at characteristically different hormonal stages: prepubertal, postpubertal, and lactating. Gonadotrope plasticity was examined at the level of the whole population and single cells at different stages by imaging both fixed and live pituitary slices. The use of a model animal providing for the identification of selectively fluorescent gonadotropes allowed the particular advantage of defining cellular plasticity specifically for gonadotropes. In vivo analyses of gonadotropes relative to vasculature showed significantly different gonadotrope distributions across physiological states. Video microscopy studies using live slices ex vivo demonstrated pituitary cell plasticity in the form of movements and protrusions in response to GnRH. As positive feedback from rising estradiol levels is important for priming the anterior pituitary gland for the LH surge, experiments provide evidence of estradiol effects on GnRH signaling in gonadotropes. The experiments presented herein provide new insight into potential plasticity of gonadotropes within the anterior pituitary glands of female mice.

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