SUCKLING DIFFERENTIALLY MODULATES HYPOTHALAMIC HORMONE RECEPTOR EXPRESSION IN LACTATION DEFICIENT OFA HR/HR RATS

PENNACCHIO GE; CARREÑO NB; JAHN GA; VALDEZ SR; SOAJE M

Congreso; 2da. Reunión Conjunta de Sociedades de Biología de la República Argentina; 2011

SUCKLING DIFFERENTIALLY MODULATES HYPOTHALAMIC HORMONE RECEPTOR EXPRESSION IN LACTATION DEFICIENT OFA HR/HR RATS Pennacchio GE1, Carreño NB1, Jahn GA1, Valdez SR1,2, Soaje, M1,3 1IMBECU-CONICET-CCT-Mendoza, Argentina, 2ICB, UNCuyo, 3FCM UNCuyo, svaldez@mendoza-conicet.gov.ar, msoaje@mendoza-conicet.gov.ar OFA hr/hr rats present lactation deficit, elevated hypothalamic DA system sensitivity, overexpression of Tyrosine Hydroxylase, partially blocked suckling-induced prolactin and oxytocin release. In an attempt to determine possible causes of the altered sensitivity of DA system we measured hypothalamic expression of PRL (the long form, PRLRlong), progesterone (PR total and PRB isoform), estrogen (ERα isoform) and thyroid hormones (TRα1, TRα2, TRβ1, TRβ2 isoforms) receptors using real time quantitative RT-PCR and serum PRL by RIA in mid-lactating rats separated from their pups for 12 h and subsequently suckled for 0 (S), 2 (S/s2h) or 4 h (S/s4h). 2 or 4 h suckling induced significant PRL release and decreased significantly mRNA levels of PRLR, ERα, TRα1, TRα2, TR β1 and TR β2 without changes in the expression of PRs (total or B isoform). These results indicate that hypothalamic PRLR, ERα, and TR expression are regulated by suckling in lactating OFA while PRs, one of the main modulators of dopaminergic hypothalamic neurons, do not change.