Circannual changes in stress and feeding hormones and their effect on food-seeking behaviors

Abstract

Seasonal fluctuations in food availability show a tight association with seasonal variations in body weight and food intake. Seasonal variations in food intake, energy storage, and expenditure appear to be a widespread phenomenon suggesting they may have evolved in anticipation for changing environmental demands. These cycles appear to be driven by changes in external daylength acting on neuroendocrine pathways. A number of neuroendocrine pathways, two of which are the endocrine mechanisms underlying feeding and stress, appear to show seasonal changes in both their circulating levels and reactivity. As such, variation in the level or reactivity to these hormones may be crucial factors in the control of seasonal variations in food-seeking behaviors. The present review examines the relationship between feeding behavior and seasonal changes in circulating hormones. We hypothesize that seasonal changes in circulating levels of glucocorticoids and the feeding-related hormones ghrelin and leptin contribute to seasonal fluctuations in feeding-related behaviors. This review will focus on the seasonal circulating levels of these hormones as well as sensitivity to these hormones in the modulation of food-seeking behaviors.

Temporal variation of diabetic ketoacidosis and hypoglycemia in adults with type 1 diabetes: A nationwide cohort study

“…Diabetic ketoacidosis results from relative or absolute insulin deficiency coupled with increased regulatory counter‐regulatory hormones . In a review of circannual hormonal changes, basal levels of glucocorticoids appear to be highest in autumn (fall) and winter and lowest in spring and summer . For example, in a study of healthy men, temporal variation was found in cortisol levels, with a peak in December .…”

Seasonal effects on plasma cortisol concentrations in the Bedouin buck: circadian studies and response to ACTH

“…For example, Barenton et al (1988) demonstrated that variation in photoperiod has a direct effect on BW: long days stimulate and short days inhibit weight gain. The HPA axis and other neuroendocrine systems may be operative in these effects in rams (Cahill et al, 2013;Ebling, 2015).…”

Neuropeptide Y and orexin immunoreactivity in the sparrow brain coincide with seasonal changes in energy balance and steroids

“…In seasonal breeders, the potential benefits of increased food availability may be offset by greater energy expenditure through reproductive activities (Hinsch, Pen, & Komdeur, 2013). In contrast, nonbreeding animals face other metabolic challenges including: low temperatures and inclement weather (De Bruijn & Romero, 2013;Metcalfe, Schmidt, Bezner Kerr, Guglielmo, & MacDougall-Shackleton, 2013;Romero, Reed, & Wingfield, 2000); reduced food availability and less foraging time with short photoperiods (Cahill, Tuplin, & Holahan, 2013;Watts & Hahn, 2012); and longer overnight fasts (Smith, Reitsma, & Marra, 2011). Seasonal differences in energetic balance are well-documented (Fokidis, Orchinik, & Deviche, 2009;Wu et al, 2014).…”