Photostimulation increases food intake, agouti-related protein (AGRP) and type II iodothyronine deiodinase (DIO2) gene expression in the medio-basal hypothalamus of Gambel's White-crowned Sparrow.

ABSTRACT: Before migration, birds express hyperphagia leading to deposition of fuel in support of long-distance flight. Long days in spring stimulate a photoperiodic neuroendocrine cascade leading to heightened food intake. A major component of the response of the reproductive system to increased daylength in birds is the local conversion of thyroxine (T4) to triiodothyronine (T3) in the medial basal hypothalamus. However, mechanisms of photostimulation regulating hyperphagia in migratory birds have yet to be resolved. We report results from two studies of Gambel's White-crowned Sparrow (Zonotrichia leucophrys gambelii), a long-distance migrant. We used quantitative PCR to measure basal hypothalamic gene expression of several neuropeptides, glucocorticoid receptors, type II and type III iodothyronin

SUBMITTER: Boswell T 

PROVIDER: S-EPMC12145944 | biostudies-literature | 2025 Jun

REPOSITORIES: biostudies-literature