IMBECU   20882
INSTITUTO DE MEDICINA Y BIOLOGIA EXPERIMENTAL DE CUYO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Regulation of thyroid hormone receptors by suckling in rats with normal or deficient lactation.
Autor/es:
VALDEZ SR; NEIRA FJ; SOAJE M; PENNACCHIO GE; JAHN GA
Lugar:
Buenos Aires
Reunión:
Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017
Institución organizadora:
Reunión Conjunta de Sociedades de Biociencias
Resumen:
During lactation, sustained hyperprolactinemia is maintained by the suckling stimulus and decreased hypothalamic sensitivity to prolactin (PRL) negative feedback, that maintains a reduced dopaminergic tone. OFA (hr/hr) rats, derived from the Sprague Dawley (SD) strain have deficient lactation, high hypothalamic dopaminergic tone and a blockade in suckling induced PRL release. Hyperthyroid rats also have deficient lactation, caused by increased hypothalamic sensitivity to PRL negative feedback that leads to a partial blockade in suckling induced PRL release. Thus, both groups show elevated dopaminergic tone responsible for the decreased PRL release and lactation failure. This evidence suggests that thyroid hormones may be also involved in prolactin regulation during lactation. We investigated the changes in hypothalamic thyroid hormone receptors (TR) expression in response to the suckling stimulus in OFA rats compared to SD rats (normal lactation). Using real time quantitative RTPCR, we measured the changes in hypothalamic mRNA expression of TRβ isoforms 1 and 2 and TRα isoforms 1 and 2, in mid-lactating OFA and SD rats, continuously suckled (CL), separated from their pups for 12 h (Sep), or separated and subsequently suckled during 2 (S2) or 4 (S4) h. We also determined serum PRL levels by RIA and litter weight gain. After suckling, PRL release and litter weight gain were higher (p