Research

Hormonal

Fasting-induced hypoglycemia triggers tanycytes to upregulate VEGF-A, which increases fenestration of hypothalamic blood vessels and reorganizes tanycytic tight junctions to allow direct access of circulating metabolic hormones (e.g., leptin, ghrelin) to appetite-regulating neurons.

Your brain has a dynamic system that monitors your energy status. When you fast or have low blood sugar, your brain cells (tanycytes) temporarily open the 'windows' to your hypothalamus, allowing hunger and satiety hormones (like leptin and ghrelin) to directly signal your brain to adjust your appetite. This is a natural, adaptive response to ensure you eat when energy is low.

GoodConditionalHIGH confidence
Fasting for 24 hours promotes a marked increase in the fenestration of ME capillary loops... This phenomenon is accompanied by a concomitant increase in the organization of tanycytic tight-junction complexes... Transcriptomic analyses have revealed that... vascular endothelial growth factor (VEGF)-A is the only growth factor upregulated in the ME upon both fasting and 2-deoxy-D-glucose treatment
Vincent Prévot et al. · Endocrine Reviews · 2018

Why this rating

Based on a comprehensive review of multiple high-quality animal studies (mice) demonstrating causal links via knockout models and pharmacological interventions.

Source

The Versatile Tanycyte: A Hypothalamic Integrator of Reproduction and Energy Metabolism

Vincent Prévot et al. · Endocrine Reviews · 2018

DOI 10.1210/er.2017-00235

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DOI resolved against Crossref · corpus check 2026-06-10

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