EFFECT OF MILD HYPERTHYROIDISM ON HYPOTHALAMIC PROLACTIN SIGNALING PATHWAY IN EARLY LACTATION

FLAVIA J. NEIRA; GISELA E. PENNACCHIO; MARTA SOAJE; J.P. MACKERN-OBERTI; GRACIELA A. JAHN; SUSANA R. VALDEZ

BUENOS AIRES

Congreso; CONGRESO SAIC-SAI-SAFIS 2019; 2018

SAIC

During late pregnancy the hypothalamic neuroendocrine control of PRL secretion adapts, decreasing dopaminergic tone, to promote adequate lactation. Previously we described that severe hyperthyroidism elevates dopaminergic tone, blunting suckling-induced prolactin (PRL) release that results in early litter death. In this work, we studied the effects of mild hyperthyroidism, which also reduces PRL secretion 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 early lactation (L2). Hypothalamic mRNA of hyperthyroid (HyperT) and control (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 members of the PRL signaling pathway (STAT5b, SOCS1 and SOCS3) was determined by RT-qPCR. TRβ2 expression decreased on L2 compared to G19 in Co and HyperT (P