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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Insulin temporal sensitivity and its signaling pathway in the rat pineal gland

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Peliciari-Garcia, Rodrigo A. [1] ; Marcal, Anderson C. [1] ; Silva, Jessica A. [1] ; Carmo-Buonfiglio, Daniella [1] ; Amaral, Fernanda G. [1] ; Afeche, Solange Castro [2] ; Cipolla-Neto, Jose [1] ; Carvalho, Carla R. O. [1]
Total Authors: 8
[1] Univ Sao Paulo, Dept Physiol & Biophys, Inst Biomed Sci 1, Sao Paulo - Brazil
[2] Butantan Inst, Pharmacol Lab, Sao Paulo - Brazil
Total Affiliations: 2
Document type: Journal article
Source: Life Sciences; v. 87, n. 5-6, p. 169-174, JUL 31 2010.
Web of Science Citations: 14

Aims: In our previous work, we reported that the insulin potentiating effect on melatonin synthesis is regulated by a post-transcriptional mechanism. However, the major proteins of the insulin signaling pathway (ISP) and the possible pathway component recruited on the potentiating effect of insulin had not been characterized. A second question raised was whether windows of sensitivity to insulin exist in the pineal gland due to insulin rhythmic secretion pattern. Main methods: Melatonin content from norepinephrine(NE)-synchronized pineal gland cultures was quantified by high performance liquid chromatography with electrochemical detection and arylalkylamine-N-acetyltransferase (AANAT) activity was assayed by radiometry. Immunoblotting and immunoprecipitation techniques were performed to establish the ISP proteins expression and the formation of 14-3-3: AANAT complex, respectively. Key findings: The temporal insulin susceptibility protocol revealed two periods of insulin potentiating effect, one at the beginning and another one at the end of the in vitro induced ``night{''}. In some Timed-insulin Stimulation (TSs), insulin also promoted a reduction on melatonin synthesis, showing its dual action in cultured pineal glands. The major ISP components, such as IR beta, IGF-1R, IRS-1, IRS-2 and PI3K(p85), as well tyrosine phosphorylation of pp85 were characterized within pineal glands. Insulin is not involved in the 14-3-3:AANAT complex formation. The blockage of PI3K by LY 294002 reduced melatonin synthesis and AANAT activity. Significance: The present study demonstrated windows of differential insulin sensitivity, a functional ISP and the PI3K-dependent insulin potentiating effect on NE-mediated melatonin synthesis, supporting the hypothesis of a crosstalk between noradrenergic and insulin pathways in the rat pineal gland. (C) 2010 Elsevier Inc. All rights reserved. (AU)

FAPESP's process: 07/07790-6 - Role of insulin on the regulation of melatonin synthesis by pineal gland: action mechanisms and functional characteristics
Grantee:Rodrigo Antonio Peliciari Garcia
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 04/06767-2 - Melatonin and the control of energy metabolism: central and peripheral actions and their interaction with other hormones
Grantee:José Cipolla Neto
Support type: Research Projects - Thematic Grants