Agouti regulation of intracellular calcium: role in the insulin resistance of viable yellow mice.

Zemel, Michael B.; Kim, Jung Han; Woychik, Richard P.; Michaud, Edward J.; Kadwell, Sue H.; Patel, Indravadan R.; Wilkison, William O.

doi:10.1073/pnas.92.11.4733

Cited by 140 publications

(91 citation statements)

References 29 publications

(21 reference statements)

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“…This effect appears to be mediated in part by the ability of ASP to act as an inhibitor of ␣MSH binding to the MC1R (24 -26). On the other hand, some studies suggest that agouti protein may act through a receptor distinct from the MC1R (27)(28)(29)(30). Indeed ASP also inhibits the melanogenic activity of agents such as forskolin and dibutyryl cAMP, which mimic the effects of ␣MSH but act downstream of the MC1R (31).…”

mentioning

confidence: 99%

Involvement of Microphthalmia in the Inhibition of Melanocyte Lineage Differentiation and of Melanogenesis by Agouti Signal Protein

Aberdam¹,

Bertolotto²,

Sviderskaya³

et al. 1998

Journal of Biological Chemistry

174

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In mouse follicular melanocytes, production of eumelanins (brown-black pigments) and pheomelanins (yellow-brownish pigments) is under the control of two intercellular signaling molecules that exert opposite actions, ␣-melanocyte-stimulating hormone (␣MSH) which preferentially increases the synthesis of eumelanins, and agouti signal protein (ASP) whose expression favors the production of hair containing pheomelanins. In this study, we report that ASP does not only affect mature melanocytes but can also inhibit the differentiation of melanoblasts. We show that both ␣MSH and forskolin promote the differentiation of murine melanoblasts into mature melanocytes and that ASP inhibits this process. We present evidence that the expression of a specific melanogenic transcription factor, microphthalmia, and its binding to an M box regulatory element, is inhibited by ASP. We also show that, in B16 murine melanoma cells, ASP inhibits ␣MSH-stimulated expression of tyrosinase, tyrosine-related proteins 1 and 2 through an inhibition of the transcription activity of their respective promoters. Further, ASP inhibits ␣MSH-induced expression of the microphthalmia gene and reduces the level of microphthalmia in the cells. Our data demonstrate that ASP can regulate both melanoblast differentiation and melanogenesis, pointing out the key role of microphthalmia in the control of these processes.

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mentioning

confidence: 99%

Involvement of Microphthalmia in the Inhibition of Melanocyte Lineage Differentiation and of Melanogenesis by Agouti Signal Protein

Aberdam¹,

Bertolotto²,

Sviderskaya³

et al. 1998

Journal of Biological Chemistry

174

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“…A possible explanation for the rise in enzyme activity may be increased enzyme expression levels in mice with AP overexpression. The action of AP on gene expression has been shown in adipose tissue and b-cells of the pancreas gland (16,17).…”

Section: Discussionmentioning

confidence: 99%

“…AP has been shown to increase the intracellular concentration of Ca 2þ in myocytes and adipocytes (14,15). It also increases gene expression in adipose tissue and the b-cells of the pancreas gland (16,17). High steroidogenic response to ACTH in A y /a mice may be a consequence of the stimulatory action of AP on plasma membrane enzyme adenylate cyclase (AC) and/or intracellular steroidogenic enzymes.…”

Section: Introductionmentioning

confidence: 99%

Ectopic Agouti protein overexpression increases stimulated corticosterone production without effect on adenylate cyclase activity in mouse adrenal cells

Shevchenko

Бажан²,

Макарова³

et al. 2004

European Journal of Endocrinology

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Objective: The antagonism of Agouti protein (AP) and Agouti-related protein on melanocortin receptors suggests an inhibitory role in the regulation of steroidogenesis. However, we have previously demonstrated that ectopic AP overexpression increased restraint-induced corticosterone release and adrenal reactivity to ACTH in mice. A high steroidogenic response to ACTH may be a consequence of a stimulatory AP action on the adenylate cyclase (AC) and/or intracellular steroidogenic enzymes. The aim of the present study was to estimate the effect of ectopic AP overexpression on the activity of AC and steroidogenic intracellular enzymes. Methods: ACTH and forskolin were used for AC stimulation, and dibutyryl cAMP and progesterone were used for stimulation of intracellular steroidogenic enzymes in isolated adrenal cells in male C57Bl/6J mice of two Agouti genotypes: A y /a (ectopic AP overexpression) and a/a (absence of AP in all tissues). Results: ACTH and forskolin increased cAMP accumulation to the same extent in both A y /a and a/a mouse adrenal cells (P , 0.001; ANOVA), but resulted in higher corticosterone production in A y /a mice (P , 0.001 for ACTH and P , 0.01 for forskolin; ANOVA). Dibutyryl cAMP-and progesterone-induced corticosterone production was higher in A y /a mice than in a/a mice (P , 0.001 for dibutyryl cAMP and P , 0.01 for progesterone; ANOVA). Conclusions: Ectopic AP overexpression increased stimulated corticosterone production and intracellular steroidogenic enzyme reactivity to cAMP without an effect on AC activity.

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“…Demonstrou-se que este estimula o influxo de cálcio em uma variedade de células e promove estoque de energia nos adipócitos, por meio do estímulo da expressão e da atividade da enzima ácido graxo sintase, chave na lipogênese de novo, ao mesmo tempo em que inibe a lipólise basal 8 . Esta acontece porque o aumento do cálcio intracelular é ligado à ativação direta da enzima fosfodiesterase-3B, que resulta em diminuição do AMPc (adenosina 3',5' monofosfato cíclico) e na consequente redução da habilidade dos agonistas em estimular a fosforilação e a ativação da enzima lipase hormônio-sensível 9 .…”

Section: N T R O D U ç ã Ounclassified

Ingestão de cálcio e indicadores antropométricos entre adolescentes

et al. 2007

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ObjetivoEste estudo teve como objetivo investigar a relação da ingestão de cálcio com indicadores antropométricos de adolescentes. MétodosForam avaliados 507 alunos de duas escolas públicas e uma particular de Ouro Preto, Minas Gerais, por meio de questionário sobre condições socioeconômicas, avaliação da maturação sexual, antropometria, composição corporal e consumo alimentar. ResultadosA ingestão média de cálcio foi 703,7 (396,0) mg/dia, sendo a maior ingestão verificada na escola de maior nível socioeconômico. Apenas 8% dos adolescentes apresentavam ingestão superior à ingestão adequada. Houve associação negativa do cálcio, ajustado para o índice de massa corporal (r=-0,203, p=0,001), na escola de médio nível socioeconômico e nos adolescentes com ingestão desse mineral entre 400 e 800mg/dia (r=-0,134, p=0,044). ConclusãoVerificou-se ingestão insuficiente de cálcio entre os adolescentes de Ouro Preto, evidenciando a necessidade de estimular o consumo de alimentos fontes desse mineral nesta população.Termos de indexação: adolescente; antropometria; cálcio; estudantes.

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Agouti regulation of intracellular calcium: role in the insulin resistance of viable yellow mice.

Cited by 140 publications

References 29 publications

Involvement of Microphthalmia in the Inhibition of Melanocyte Lineage Differentiation and of Melanogenesis by Agouti Signal Protein

Involvement of Microphthalmia in the Inhibition of Melanocyte Lineage Differentiation and of Melanogenesis by Agouti Signal Protein

Ectopic Agouti protein overexpression increases stimulated corticosterone production without effect on adenylate cyclase activity in mouse adrenal cells

Ingestão de cálcio e indicadores antropométricos entre adolescentes

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