Effect of mild hyperthyroidism on hypothalamic prolactin signaling pathway in early lactation.

NEIRA FJ; PENNACCHIO GE; SOAJE M; MACKERN OBERTI JP; JAHN GA; VALDEZ SR

Mar del Plata

Congreso; LXIII Reunión Científica Anual de la Sociedad Argentina de Investigación Clínica; 2018

Sociedad Argentina de Investigación Clínica

During late pregnancy the hypothalamic neuroendocrine control ofPRL secretion adapts, decreasing dopaminergic tone, to promoteadequate lactation. Previously we described that severe hyperthyroidismelevates dopaminergic tone, blunting suckling-induced prolactin(PRL) release that results in early litter death. In this work, westudied the effects of mild hyperthyroidism, which also reduces PRLsecretion but allows the maintenance of lactation and litter survival,on hypothalamic regulation of PRL secretion using a dose of T4(0.1mg/ml/kg/day, s.c.) on late pregnancy (day 19, G19) and earlylactation (L2). Hypothalamic mRNA of hyperthyroid (HyperT) andcontrol (Co) rats was obtained and the expression of receptors (R)of thyroid hormone (TRα1, TRβ1, TRβ2), progesterone (PR, PRB),estrogen (ERα, ERβ) and prolactin (PRLR Long isoform) and membersof the PRL signaling pathway (STAT5b, SOCS1 and SOCS3)was determined by RT-qPCR. TRβ2 expression decreased on L2compared to G19 in Co and HyperT (P