INVESTIGADORES
JAHN Graciela Alma
congresos y reuniones científicas
Título:
Hypothalamic expression of TH and PRL signaling pathway during lactation in Sprague-Dawley and OFA hr/hr rats.
Autor/es:
PENNACCHIO GE; CARREÑO NB; ROSALES JA; JAHN GA; VALDEZ SR; SOAJE M
Lugar:
Potrero de los Funes
Reunión:
Congreso; XXX Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2012
Institución organizadora:
Sociedad de Biología de Cuyo
Resumen:
The OFA hr/hr (OFA) strain of rats, derived from Sprague-Dawley (SD) rats has deficient lactation and high hypothalamic dopaminergic tone. During lactation, sustained hyperprolactinemia is due to suckling stimulus and decreased sensitivity to prolactin (PRL) negative feedback. We studied the regulation of signaling pathways involved in the activation of dopaminergic neurons during lactation in OFA and SD rats. Using real time quantitative reverse transcriptase-polymerase chain reaction we measured the changes in mRNA expression of tyrosine hydroxylase (TH, limiting enzyme for dopamine synthesis), long PRL receptor (PRLR), STAT5b (required for the negative-feedback action of PRL on hypothalamic dopaminergic neurons), SOCS-1, SOCS-3, CIS (proteins that disrupt downstream STAT translocation to the nucleus to suppress prolactin signaling) in medial basal hypothalamus (MBH) in OFA and SD rats during continuous breastfeeding (LC) and separated rats from their pups for 12 h (S/ss). The results were correlated with serum PRL levels measured by RIA. Removal the litter increased TH expression and decreased serum PRL in SD and OFA rats. PRLR expression decreased in separated SD rats and no change in STAT5b and SOCS1 was observed in both strains. Separation decreased CIS expression in both strains and SOCS 3 expression only in the OFA rats. Suckling and/or PRL levels differentially regulate the expression of RPRLL in both strains of rats. The reduced expression of SOCS3 in OFA rats during lactation may suggest that the inhibitory signaling pathway of PRL in this strain is altered and may partly explain its lactation failure.