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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.)

Fasting reduces the number of TRH immunoreactive neurons in the hypothalamic paraventricular nucleus of male rats, but not in mice

Full text
Author(s):
Campos, Ana M. P. [1] ; Wasinski, Frederick [1] ; Klein, Marianne O. [2] ; Bittencourt, Jackson C. [2] ; Metzger, Martin [1] ; Donato Jr, Jose
Total Authors: 6
Affiliation:
[1] Univ Sao Paulo, Inst Ciencias Biomed, Dept Fisiol & Biofis, Sao Paulo - Brazil
[2] Univ Sao Paulo, Inst Ciencias Biomed, Dept Anat, Sao Paulo - Brazil
Total Affiliations: 2
Document type: Journal article
Source: Neuroscience Letters; v. 752, MAY 1 2021.
Web of Science Citations: 0
Abstract

During fasting or weight loss, the fall in leptin levels leads to suppression of thyrotropin-releasing hormone (TRH) expression in the paraventricular nucleus of the hypothalamus (PVH) and, consequently, inhibition of the hypothalamic-pituitary-thyroid (HPT) axis. However, differently than rats, just few PVHTRH neurons express the leptin receptor in mice. In the present study, male adult rats and mice were submitted to 48-h fasting to evaluate the consequences on proTRH peptide expression at the PVH level. Additionally, the proTRH peptide expression was also assessed in the brains of leptin-deficient (Lep(ob/ob)) mice. We observed that approximately 50 % of PVHTRH neurons of leptin-injected rats exhibited phosphorylation of the signal transducer and activator of transcription 3 (pSTAT3), a marker of leptin receptor activation. In contrast, very few PVHTRH neurons of leptin-injected mice exhibited pSTAT3. Rats submitted to 48-h fasting showed a significant reduction in the number of PVHTRH immunoreactive neurons, as compared to fed rats. On the other hand, no changes in the number of PVHTRH immunoreactive neurons were observed between fasted and fed mice. Next, the number of TRH immunoreactive cells was determined in the PVH, dorsomedial nucleus of the hypothalamus and nucleus raphe pallidus of Lep(ob/ob) and wild-type mice and no significant differences were observed, despite reduced plasma T4 levels in Lep(ob/ob) mice. Taken together, these findings provide additional evidence of the important species-specific differences in the mechanisms used by fasting and/or leptin to regulate the HPT axis. (AU)

FAPESP's process: 16/02224-1 - The existence of neurogenesis during the lactation period
Grantee:Jackson Cioni Bittencourt
Support Opportunities: Research Projects - Thematic Grants
FAPESP's process: 17/16473-6 - Processing of aversive stimuli: circuitry between the laterodorsal tegmental nucleus, the habenula, and dorsal and median raphe nuclei
Grantee:Martin Andreas Metzger
Support Opportunities: Regular Research Grants
FAPESP's process: 17/17998-5 - Evaluating chronic administration of melanin concentrating hormone (MCH) effects in lactating Long-Evans rats
Grantee:Marianne Orlandini Klein
Support Opportunities: Scholarships in Brazil - Post-Doctoral
FAPESP's process: 16/20897-3 - Role of orexin neurons as mediators of the central effects induced by growth hormone
Grantee:Frederick Wasinski
Support Opportunities: Scholarships in Brazil - Post-Doctoral