Differences between rats and mice in the leptin action on the paraventricular nucleus of the hypothalamus: Implications for the regulation of the hypothalamic-pituitary-thyroid axis

Autor(es)

Campos, Ana M. P. ; Teixeira, Pryscila D. S. ; Wasinski, Frederick ; Klein, Marianne O. ; Bittencourt, Jackson C. ; Metzger, Martin ; Donato, Jose, Jr.

• Tipo de documento: Artigo Científico
• Fonte: Journal of Neuroendocrinology; v. 32, n. 9, p. 11-pg., 2020-08-24.

Resumo

Previous studies indicate that leptin regulates the hypothalamic-pituitary-thyroid (HPT) axis via direct and indirect mechanisms. The indirect mechanism involves leptin action in pro-opiomelanocortin (POMC)- and agouti-related peptide (AgRP)-expressing neurones. These cells innervate the paraventricular nucleus of the hypothalamus (PVH) where they modulate hypophysiotrophic thyrotrophin-releasing hormone (TRH)-producing neurones. The direct mechanism involves the expression of leptin receptor (LepR) in a subpopulation of PVH TRH neurones. However, to our knowledge, the existence of LepR in PVH TRH neurones of mice has not been clearly confirmed. Therefore, we investigated possible species-specific differences between rats and mice with respect to the mechanisms recruited by leptin to regulate the HPT axis. We observed that an acute leptin injection induced phosphorylated signal transducer and activator of transcription 3 (pSTAT3), a marker of leptin-responsive cells, in 46.2 +/- 8.0% of PVH proTRH immunoreactive neurones in rats. By contrast, an insignificant number of proTRH positive neurones in the mouse PVH co-expressed leptin-induced pSTAT3 or LepR. Similarly, central leptin injection increased the percentage of PVH proTRH neurones containing cAMP response element-binding protein phosphorylation in rats, but not in mice. We investigated the innervation of AgRP and POMC axons in the PVH and observed that rats exhibited a denser POMC innervation in the PVH compared to mice, whereas rats and mice showed similar density of AgRP axons in the PVH. In conclusion, rats and mice exhibit important species-specific differences in the direct and indirect mechanisms used by leptin to regulate the HPT axis. (AU)

• Processo FAPESP: 16/02224-1 - A existência da neurogênese durante o período da lactação
• Beneficiário: Jackson Cioni Bittencourt
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 17/17998-5 - Avaliação dos efeitos da administração crônica do hormônio concentrador de melanina (MCH) em ratas Long-Evans lactantes
• Beneficiário: Marianne Orlandini Klein
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 16/20897-3 - Papel dos neurônios orexina como mediadores dos efeitos centrais induzidos pelo hormônio do crescimento
• Beneficiário: Frederick Wasinski
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 17/02983-2 - Ação do hormônio do crescimento no sistema nervoso: relevância para as funções neurais e na doença
• Beneficiário: Jose Donato Junior
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 17/16473-6 - Processamento de estímulos aversivos: circuitaria entre o núcleo tegmental laterodorsal, a habênula, e os núcleos dorsal e mediano da rafe
• Beneficiário: Martin Andreas Metzger
• Modalidade de apoio: Auxílio à Pesquisa - Regular