RESEARCH ARTICLE


Effect of a High-Fat Diet on 24-Hour Pattern in Expression of Prolactin and Redox Pathway Enzymes in the Rat Adenohypophysis



Pilar Cano1, Daniel P. Cardinali*, 2, Vanesa Jimenez-Ortega1, Maria J. Rios-Lugo1, Pablo A. Scacchi2, Ana I. Esquifino1
1 Department of Biochemistry and Molecular Biology III, School of Medicine, Universidad Complutense, Madrid 28040, Spain
2 Department of Teaching and Research, Faculty of Medical Sciences, Pontificia Universidad Católica Argentina, 1107 Buenos Aires, Argentina


© 2010 Cano et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: https://creativecommons.org/licenses/by/4.0/legalcode. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Department of Teaching and Research, Faculty of Medical Sciences, Pontificia Universidad Católica Argentina, 1107 Buenos Aires, Argentina; Tel/Fax: 54 11 43590200, Int. 2310; E-mail: danielcardinali@uca.edu.ar, danielcardinali@fibertel.com.ar


Abstract

The effect of a high-fat diet (35% fat) on 24-h changes in expression of prolactin and redox pathway enzyme genes was examined in the anterior pituitary of male rats. When body weight of high-fat fed rats attained values about 20- 25 % higher than controls (after 66 days of treatment) animals were sacrificed at 6 different time intervals throughout a 24-h cycle. Anterior pituitary mRNA levels were measured by real-time PCR analysis. In control rats expression of the prolactin gene peaked in anterior pituitary at early scotophase, 3 h in advance to the peak in plasma prolactin levels. In high-fat fed rats this correlation was lost. A disruption of 24-h rhythmicity of pituitary gene expression of heme oxygenase (HO)-2, Cu/Zn- superoxide dismutases (SOD), Mn-SOD, catalase, glutathione peroxidase (GPx) and glutathione reductase (GR) was apparent in high-fat fed rats. Anterior pituitary mRNA levels for nitric oxide synthase (NOS)-2 and HO-2, Cu/Zn- and Mn- SOD and catalase augmented in high-fat fed rats, whereas those of GPx and GR decreased. The results indicate a disrupted coordination between prolactin gene expression and prolactin release in highfat fed rats that comes along with a disturbed expression of redox enzyme genes in the anterior pituitary.

Keywords: High fat diet, circadian rhythms, gene expression, anterior pituitary, prolactin, nitric oxide synthase, heme oxygenase, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase.