Effect of Pyridoxine on Human Hypophyseal Trophic Hormone Release: A Possible Stimulation of Hypothalamic Dopaminergic Pathway.

Delitala, G.; Masala, A.; Alagna, S.; Devilla, L.

doi:10.1210/jcem-42-3-603

Cited by 49 publications

(10 citation statements)

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“…However, androstenedione works antagonistically with estrogen and PRL if these are elevated then testosterone levels decrease. PRL inhibits the release of gonadotropin-releasing hormone (GnRH) which is released from the hypothalamus (Delitala, 2009), some studies suggest that testosterone regulates the secretion of prolactin through a long feedback mechanism (Gill-Sharma, 2008). Estrogens are known to stimulate growth of pituitary and also to promote PRL release resulting in elevated PRL levels systemically (Perez et al, 1986).…”

Section: Discussionmentioning

confidence: 99%

Relationship Between Some Biochemical Parameters and Hormones in Milk and Serum Associated to Reproduction in She Camel

Ibrahim¹,

Elmetwaly²

2017

AJVS

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Key words:she camel; milk; serum; correlation; regression; hormonal analysis; biochemical parameters, nitric oxide, lysozyme.This study is a trial to determine some hormonal and biochemical parameters levels in milk versus their levels in camels sera in order to be an easier available tool for better management, treatment, or prevention of infertility problems. For this trial, 70 apparently healthy dromedary she camels (6-12 years old) of average weight 520 kg were used. Milk and blood samples of the same camels were analyzed to the same parameter ; progesterone (P4), estradiol 17β (E2), total triiodothyronine (T3), total thyroxin (T4) testosterone (T), cortisol(C), prolactin (PRL),total protein (TP), albumin (ALB), nitric oxide (NO) and lysozyme (LYS). Data were analyzed by correlation and regression test. Correlation analysis revealed significant positive correlations of P4, E2, T3, T4 and PRL hormones concentrations in serum and their milk concentration; While, there was no correlation between testosterone and cortisol concentrations in serum and their milk levels. Significant positive correlation relationships were found between serum P4 level and both serum and milk T3 level. Also, significant positive correlation relationships were found between serum T3 levels and both serum and milk T4 level. On the other hand, significant negative correlations were found between serum E2 level and both serum and milk T3 level. Regression analysis revealed equations for determination of P4, E2, T3 and T4. Our results indicated that there is a significant positive correlation between most of the hormone profiles in milk and that of blood. Therefore, measuring hormone concentrations in milk seem to be a good estimate of the average hormone content in serum. We try to find a tool to help the herd managers and veterinarians to overcome causes of poor reproductive performance of camels especially problems associated with heat detection and pregnancy diagnosis for improve reproductive performance.

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Section: Discussionmentioning

confidence: 99%

Relationship Between Some Biochemical Parameters and Hormones in Milk and Serum Associated to Reproduction in She Camel

Ibrahim¹,

Elmetwaly²

2017

AJVS

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“…Reports on effects of PLP on PRL and GH secretion in vivo have been contradictory (13)(14)(15)(16)(17)(18). Vitamin B6 may act on neural function in vivo through its involvement as a cofactor for dopamine.…”

Section: Discussionmentioning

confidence: 99%

“…Administration of vitamin B6 (either 300 mg acute infusion or 400-600 mg orally daily for 2-3 months) to human volunteers (13)(14)(15)(16) reduced circulating PRL levels (13,14,16), but PLPinduced GH reduction was only observed in acromegaly (14) and in infants (15). Vitamin B6induced hormone suppression was not reproduced in other in vivo studies (17,18).…”

Section: Introductionmentioning

confidence: 99%

Pyridoxal Phosphate Inhibits Pituitary Cell Proliferation and Hormone Secretion

Ren

Melmed

2006

Endocrinology

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Pyridoxal phosphate (PLP), a bioactive form of pyridoxine, dose-dependently (10-1000 microm) inhibited cell proliferation in rat pituitary MMQ and GH3 cells and in mouse AtT-20 cells. After 4 d, MMQ cell numbers were reduced by up to 81%, GH3 cell numbers were reduced by up to 64% (P < 0.05), and AtT-20 cell numbers were reduced by up to 90%. Cell proliferation rates recovered and dose-dependently reverted to control levels after PLP withdrawal. After 4 d, PLP (400 and 1000 microm) decreased [3H]thymidine incorporation by up to 71% (P < 0.05). PLP (400-1000 microm) reduced GH3 cell GH and prolactin secretion and AtT-20 cell ACTH secretion (adjusted for cell number) by approximately 70% after 2 d. The 100 microm PLP also inhibited prolactin secretion (65%, P < 0.05) in primary rat pituitary cells treated for 2 d. PLP decreased the percentage of AtT-20 and GH3 cells in S phase and increased those in G0-G1 phase. Furthermore, PLP induced AtT-20 and GH3 cell apoptosis (28 vs. 6, P < 0.05; 26 vs. 3, P < 0.05, respectively) and dose-dependently reduced content of the antiapoptosis gene Bcl-2. These results indicate that pharmacological doses of PLP inhibit pituitary cell proliferation and hormone secretion, in part mediated through PLP-induced cell-cycle arrest and apoptosis. Pyridoxine may therefore be appropriate for testing as a relatively safe drug for adjuvant treatment of hormone-secreting pituitary adenomas.

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“…The therapeutic use o f these compounds will be presented in the part of this review concerned with clinical aspects o f lactogenic hormones. Pyridoxine (vitamin B6), acting as a coenzyme to stimulate the synthesis of DA, has been claimed to suppress PRL secretion (156,157), but these findings have not been confirmed (158 161). Among these sympathicomimetic compounds, amphetamine has been found to moderately elevate basal PRL and augment spiking in one case studied (150).…”

Section: Drugs In Clinical Use Modifying the Secretion Of Pr Lmentioning

confidence: 99%

Prolactin

Pozo¹,

Brownell²

1979

Horm Res

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The role of neurotransmitters in the release of prolactin (PRL) is reviewed. Special attention is paid to dopamine (DA) as the possible prolactin-inhibiting factor (PIF). Among other agents, estrogens alone can act directly on the pituitary galactotropes without involving hypothalamic factors. Peripherally, in addition to its stimulatory action on mammary tissue, PRL exerts a permissive role on ovarian steroidogenesis. A possible physiological action of this hormone on the regulation of adrenal function remains uncertain. The secretory rhythms of PRL are described and the mechanisms involved are discussed. A number of drugs can modify the secreting pattern of PRL mainly by acting on the dopaminergic control mechanisms. The usefulness of such agents in the clinical evaluation of galactotrope cell function is reviewed.

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Effect of Pyridoxine on Human Hypophyseal Trophic Hormone Release: A Possible Stimulation of Hypothalamic Dopaminergic Pathway.

Cited by 49 publications

References 0 publications

Relationship Between Some Biochemical Parameters and Hormones in Milk and Serum Associated to Reproduction in She Camel

Relationship Between Some Biochemical Parameters and Hormones in Milk and Serum Associated to Reproduction in She Camel

Pyridoxal Phosphate Inhibits Pituitary Cell Proliferation and Hormone Secretion

Prolactin

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