The role of dopamine in methylene blue-mediated inhibition of estradiol benzoate-induced anterior pituitary hyperplasia in rats

Nedvı́dková, J; Pacák, Karel; Haluzı́k, Martin; Nedvidek, Jan; Schreiber, V

doi:10.1016/s0304-3940(01)01752-9

Cited by 6 publications

(10 citation statements)

References 13 publications

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“…MB has been shown to modulate the physiological actions of hormones involved in the hypothalamo-pituitary-peripheral axis (Nedvídkova et al, 1995; 2000; 2001). For example, MB raises blood thyroxine and causes a feedback decrease in the serum thyroid stimulating hormone level (Nedvídkova et al, 1995).…”

Section: Methylene Blue and The Neuroendocrine Systemmentioning

confidence: 99%

“…Estradiol-induced adenohypophyseal enlargement and the enhancement of prolactin secretion are antagonized by MB (Nedvídkova et al, 2000; 2001). Treatment with MB also prevents estradiol-induced decreases in anterior pituitary dopamine levels and increases in D2 receptor number.…”

Section: Methylene Blue and The Neuroendocrine Systemmentioning

confidence: 99%

“…Treatment with MB also prevents estradiol-induced decreases in anterior pituitary dopamine levels and increases in D2 receptor number. MB alone reduces anterior pituitary weight, increases anterior pituitary dopamine concentrations and decreases anterior pituitary D2 receptor number with a corresponding reduction in its affinity (Nedvídkova et al, 2000; 2001). It is likely that inhibition of estradiol actions in the anterior pituitary by MB is mediated by elevations in dopamine levels induced by the actions of MB on receptor binding and monoamine oxidase activity (see below).…”

Section: Methylene Blue and The Neuroendocrine Systemmentioning

confidence: 99%

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Cellular and molecular actions of Methylene Blue in the nervous system

Öz

Lorke

Al‐Hasan

et al. 2010

Medicinal Research Reviews

359

249

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Methylene Blue (MB), following its introduction to biology in the 19 th century by Ehrlich, has found uses in various areas of medicine and biology. At present, MB is the first line of treatment in methemoglobinemias, is used frequently in the treatment of ifosfamide-induced encephalopathy, and is routinely employed as a diagnostic tool in surgical procedures. Furthermore, recent studies suggest that MB has beneficial effects in Alzheimer's disease and memory improvement. Although the modulation of the cGMP pathway is considered the most significant effect of MB, mediating its pharmacological actions, recent studies indicate that it has multiple cellular and molecular targets. In the majority of cases, biological effects and clinical applications of MB are dictated by its unique physicochemical properties including its planar structure, redox chemistry, ionic charges, and light spectrum characteristics. In this review article, these physicochemical features and the actions of MB on multiple cellular and molecular targets are discussed with regard to their relevance to the nervous system.

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Section: Methylene Blue and The Neuroendocrine Systemmentioning

confidence: 99%

Section: Methylene Blue and The Neuroendocrine Systemmentioning

confidence: 99%

Section: Methylene Blue and The Neuroendocrine Systemmentioning

confidence: 99%

See 1 more Smart Citation

Cellular and molecular actions of Methylene Blue in the nervous system

Öz

Lorke

Al‐Hasan

et al. 2010

Medicinal Research Reviews

359

249

View full text Add to dashboard Cite

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“…E 2 has been known to augment PRL gene expression [Stone et al, 1977;Maurer, 1982;Borgundvaag et al, 1992;Watters et al, 2000], the percentage of cells secreting PRL [Larson and Wise, 1991], the intracellular Ca 2þ concentration [Shin et al, 1993], and the PKC isozyme expression and total activity [Maeda and Lloyd, 1993]. E 2 also reduced DA receptor [Kochman et al, 1989;Nedvidkova et al, 2001], DA-inhibited adenylyl cyclase activity as well as the expression of inhibitory G-proteins (G ia3 /G o ) in lactotropes [Borgundvaag and George, 1988;Maus et al, 1989;Livingstone et al, 1998]. Although we did not observe significant effect of aging on basal PRL secretion stimulated by E 2 alone, all of these E 2 -regulated events may affect pituitary responsiveness to DA.…”

Section: Discussionmentioning

confidence: 99%

Differential involvement of protein kinase C in basal versus acetylcholine‐regulated prolactin secretion in rat anterior pituitary cells during aging

Pu¹,

Liu²

2002

J of Cellular Biochemistry

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Although it is well known that plasma concentration of prolactin (PRL) increases during aging in rats, how the anterior pituitary (AP) aging per se affects PRL secretion remains obscure. The objectives of this study were to determine if changes in the pituitary PRL responsiveness to acetylcholine (ACh; a paracrine factor in the AP), as compared with that to other PRL stimulators or inhibitors, contribute to the known age-related increase in PRL secretion, and if protein kinase C (PKC) is involved. We also determined if replenishment with aging-declined hormones such as estrogen/thyroid hormone influences the aging-caused effects on pituitary PRL responses. AP cells were prepared from old (23-24-month-old) as well as young (2-3-month-old) ovariectomized rats. Cells were pretreated for 5 days with diluent or 17beta-estradiol (E(2); 0.6 nM) in combination with or without triiodothyronine (T(3); 10 nM). Then, cells were incubated for 20 min with thyrotropin-releasing hormone (TRH; 100 nM), angiotensin II (AII; 0.2-20 nM), vasoactive intestinal peptide (VIP; 10(-9)-10(-5) M), dopamine (DA; 10(-9)-10(-5) M), or ACh (10(-7)-10(-3) M). Cells were also challenged with ACh, TRH, or phorbol 12-myristate 13-acetate (PMA; 10(-6) M) following PKC depletion by prolonged PMA (10(-6) M for 24 h) pretreatment. We found that estrogen priming of AP cells could reverse the aging-caused effects on pituitary PRL responses to AII and DA. In hormone-replenished cells aging enhanced the stimulation of PRL secretion by TRH and PMA, but not by AII and VIP. Aging also reduced the responsiveness of cells to ACh and DA in suppressing basal PRL secretion, and attenuated ACh inhibition of TRH-induced PRL secretion. Furthermore, ACh suppressed TRH-induced PRL secretion mainly via the PMA-sensitive PKC in the old AP cells, but via additional mechanisms in young AP cells. On the contrary, basal PRL secretion was PKC (PMA-sensitive)-independent in the old AP cells, but dependent in the young AP cells. Taken together, these results suggest differential roles of PMA-sensitive PKC in regulating basal and ACh-regulated PRL responses in old versus young AP cells. The persistent aging-induced differences in AP cell responsiveness to ACh, DA, TRH, and PMA following hormone (E(2)/T(3)) replenishment suggest an intrinsic pituitary change that may contribute, in part, to the elevated in vivo PRL secretion observed in aged rats.

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“…Similar interaction is assumed to occur between growth factors and their receptors leading to a decrease in the rate of apoptosis in tissues undergoing hyperplasia [13][14][15] . The role of the receptors stimulation or blockade in pituitary cell proliferation is well illustrated by N-Methyl-D-Aspartate (NMDA), dopamine (D-2), cannabinoid CB1 and leptin recep- tors [16][17][18][19][20][21] . .or example, NMDA receptor activation inhibits cell proliferation and promotes cell death, while its blockade promotes cells to go through the cell cycle [16][17][18] .…”

Section: Molecular Basis O Pituitary Hyperplasiamentioning

confidence: 99%

Pituitary Hyperplasia

Al-Gahtany¹,

Horváth²,

Kovács³

2003

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Pituitary hyperplasia is rare, difficult to diagnose and sometimes controversial. The hyperplasia could be physiologic which is usually reversible, or pathologic which varies in presentation from incidental to tumor like lesion with and without hormonal disturbance. Any pituitary cell is capable of undergoing hyperplasia in the presence of the right stimuli. In this article we summarize the various pathologic and morphologic features of each subtype of pituitary hyperplasia, give an account of the molecular, hormonal and cellular basis of this condition and outline its clinical significance, differential diagnosis and prognosis.

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The role of dopamine in methylene blue-mediated inhibition of estradiol benzoate-induced anterior pituitary hyperplasia in rats

Cited by 6 publications

References 13 publications

Cellular and molecular actions of Methylene Blue in the nervous system

Cellular and molecular actions of Methylene Blue in the nervous system

Differential involvement of protein kinase C in basal versus acetylcholine‐regulated prolactin secretion in rat anterior pituitary cells during aging

Pituitary Hyperplasia

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