Endocrine

, Volume 33, Issue 2, pp 118–125

Effect of a high-fat diet on 24-h pattern of circulating levels of prolactin, luteinizing hormone, testosterone, corticosterone, thyroid-stimulating hormone and glucose, and pineal melatonin content, in rats

  • Pilar Cano
  • Vanesa Jiménez-Ortega
  • Álvaro Larrad
  • Carlos F. Reyes Toso
  • Daniel P. Cardinali
  • Ana I. Esquifino
Original Paper

DOI: 10.1007/s12020-008-9066-x

Cite this article as:
Cano, P., Jiménez-Ortega, V., Larrad, Á. et al. Endocr (2008) 33: 118. doi:10.1007/s12020-008-9066-x

Abstract

Circadian rhythmicity is affected in obese subjects. This article analyzes the effect of a high-fat diet (35% fat) on 24-h changes circulating prolactin, luteinizing hormone (LH), testosterone, corticosterone, thyroid-stimulating hormone (TSH) and glucose, and pineal melatonin content, in rats. When body weight of rats reached the values of morbid obesity, the animals were sacrificed at six different time intervals throughout a 24-h cycle, together with age-matched controls fed a normal diet (4% fat). Plasma hormone levels were measured by specific radioimmunoassays and glucose concentration by an automated glucose oxidase method. In rats under a high-fat diet, a significant disruption of the 24-h pattern of plasma TSH, LH, and testosterone and a slight disruption of prolactin rhythm were found. Additionally, high-fat fed rats showed significantly lower total values of plasma TSH and testosterone and absence of correlation between testosterone and circulating LH levels. Plasma corticosterone levels increased significantly in high-fat fed rats and their 24-h variation became blunted. In obese animals, a significant hyperglycemia developed, individual plasma glucose values correlating with circulating corticosterone in high-fat fed rats only. The amplitude of the nocturnal pineal melatonin peak decreased significantly in high-fat fed rats. The results underlie the significant effects that obesity has on circadian organization of hormone secretion.

Keywords

Circadian High-fat diet Obesity Hyperglycemia Melatonin Prolactin 

Copyright information

© Springer Science+Business Media, LLC 2008

Authors and Affiliations

  • Pilar Cano
    • 1
  • Vanesa Jiménez-Ortega
    • 1
  • Álvaro Larrad
    • 1
  • Carlos F. Reyes Toso
    • 2
  • Daniel P. Cardinali
    • 2
  • Ana I. Esquifino
    • 1
  1. 1.Departamento de Bioquímica y Biología Molecular III, Facultad de MedicinaUniversidad ComplutenseMadridSpain
  2. 2.Departamento de Fisiología, Facultad de MedicinaUniversidad de Buenos AiresBuenos AiresArgentina

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