Effect of restricted feeding on nocturnality and daily leptin rhythms in OVLT in aged male Wistar rats

Abstract

Circadian system has direct relevance to the problems of modern lifestyle, shift workers, jet lag etc. To understand non-photic regulation of biological clock, the effects of restricted feeding (RF) on locomotor activity and daily leptin immunoreactivity (ir) rhythms in three age groups [3, 12 and 24 months (m)] of male Wistar rats maintained in light:dark (LD) 12:12 h conditions were studied. Leptin-ir was examined in the suprachiasmatic nucleus (SCN), the medial preoptic area (MPOA) and organum vasculosum of the lamina terminalis (OVLT). Reversal of feeding time due to restricted food availability during daytime resulted in switching of the animals from nocturnality to diurnality with significant increase in day time activity and decrease in night time activity. The RF resulted in % diurnality of approximately 32, 29 and 73 from % nocturnality of 82, 92 and 89 in control rats of 3, 12 and 24 m age, respectively. The increase in such switching from nocturnality to diurnality with restricted feeding was found to be robust in 24 m rats. The OVLT region showed daily leptin-ir rhythms with leptin-ir maximum at ZT-0 in all the three age groups. However leptin-ir levels were minimum at ZT-12 in 3 and 12 m though at ZT-18 in 24 m. In addition the mean leptin-ir levels decreased with increase in food intake and body weight significantly in RF aged rats. Thus we report here differential effects of food entrained regulation in switching nocturnality to diurnality and daily leptin-ir rhythms in OVLT in aged rats.

Shift-work: is time of eating determining metabolic health? Evidence from animal models

“…The effect of shifting food to the light period on body weight gain is quite clear. In ten studies using 12 h day feeding, animals gained significantly more body weight ( 61 , 64 , 76 – 78 , 81 – 84 , 87 ) ; in four studies, animals remained similar to controls ( 79 , 80 , 85 , 86 ) . In two studies, where authors did not find differences in body weight gain ( 79 , 80 ) , this was associated with decreased food consumption.…”

“…Disrupted circadian rhythms were observed in the fluctuations of clock genes in the liver, muscle and heart (61,(78)(79)(80)(81)(82)(83) . Studies also report loss of temperature rhythms, shifted locomotor activity towards the rest phase, shifted glucose, TAG, leptin and ghrelin rhythms and decreased leptin immunoreactivity rhythms in the organum vasculosum of the lamina terminals (61,64,(78)(79)(80)(81)(82)(83)(84)(85)(86) . In the study of Ramirez-Plascencia et al (87) , authors described shifted or blunted activity rhythms of orexin, melanin-concentrating hormone and α-melanocortin-stimulating hormone neurons in the hypothalamus.…”

“…Among rodents that gained weight, metabolic dysfunction was reported, mainly fat mass accumulation, dyslipidaemia, high glucose levels and glucose intolerance, decreased insulin sensitivity, lower RER, decreased energy expenditure and disrupted circadian rhythms of metabolic genes in the liver and muscle (61,(76)(77)(78)(82)(83)(84)87) .…”

“…Shift-work: is time of eating determining metabolic health? Reddy & Jagota (84) Shifted Reznick et al (80) Shifted (86) HFD, high-fat diet; LH-PeF, lateral hypothalamus-perifornical area; LD, light-dark; MCH, melanin-concentrating hormone; α-MSH, α-melanocyte-stimulating hormone; NE, not explored; ORX, orexin; OVLT, organum vasculosum lamina terminalis; ↑ increased; ↓ decreased.…”

Efecto del horario de alimentación en el ritmo circadiano, obesidad y alteraciones metabólicas relacionadas: revisión sistemática

“…Esto reforzaría lo observado en trabajadores por turnos, en los que se ve reducida la tolerancia a la glucosa. alimentación, que actuaría separado de la luz (312,313) .…”