INDUCTION OF HYPOTHALAMIC THYROID RECEPTORS EXPRESSION BY SUCKLING STIMULUS

PENNACCHIO GISELA E; PARRILLA JÉSSICA NADINE; JAHN GRACIELA A; VALDEZ SUSANA R; SOAJE MARTA

Mendoza

Congreso; XXXI Reunión Anual de la Sociedad de Biología de Cuyo; 2013

Sociedad de Biología de Cuyo

During lactation there are adaptations to enhance the metabolic efficiency with the aim to make sure the supply of the nutrient needs of an animal. Suckling is an important stimulant of PRL secretion and food intake and thyroid status is involved in the adaptations of the lactation. In an attempt to determine changes in the thyroid status in response to suckling, we determined by real-time PCR the expression of thyroid hormones receptors (TRα1,TRα2, TRβ1, TRβ2 isoforms) and two members of the family of nuclear co-regulators of hormone thyroid (NCOR1 y NCOR2) in medial basal hypothalamus (MBH) using real time quantitative RT-PCR and serum PRL, T3 and T4 hormones by RIA in mid-lactating Sprague Dawley rats separated from their pups for 12 h and subsequently suckled for 0 (S), 2 (S/s2h) or 4 h (S/s4h). Serum PRL, T3 and T4 were measured by RIA. 2 or 4 h suckling increased significantly PRL, T3 and T4 release (p<0.05 vs S) and induced significantly the expression TRα1, TRα2, TR β1 and TR β2 (p<0.01 vs S) without changes in the expression of NCOR1 and NCOR2.These results indicate that hypothalamic TRs expression is induced by suckling in lactating in correlation with an increase in T3, T4 and PRL levels. Suckling stimulus may mediate metabolic changes in MBH that involve the participation of TRs. Since the emerging roles of co-regulators in homeostasis we will explore other members of their family implicated in metabolism in lactation.