INBIOMED   24026
INSTITUTO DE INVESTIGACIONES BIOMEDICAS
Unidad Ejecutora - UE
artículos
Título:
Anterior Pituitary gland synthesizes Dopamine from L‐3,4‐dihydroxyphenylalanine (L‐Dopa)
Autor/es:
DE DIOS, NATALY; IMSEN, MERCEDES; FERRARIS, JIMENA; ASAD, ANTONELA SOFÍA; ROMERO, ANA CLARA; PISERA, DANIEL; ORRILLO, SANTIAGO JORDI; DE FINO, FERNANDA; ZÁRATE, SANDRA
Revista:
JOURNAL OF NEUROENDOCRINOLOGY.
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Año: 2020 vol. 32
ISSN:
0953-8194
Resumen:
Prolactin (PRL) is a hormone principally secreted by lactotrophs of the anterior pituitary gland. Although the synthesis and exocytosis of this hormone are mainly under the regulation of hypothalamic dopamine (DA), the possibility that the anterior pituitary synthesizes this catecholamine remains unclear. In this study, our aim was to determine if the anterior pituitary produces DA from the precursor L-Dopa. To this purpose, we studied the expression of aromatic L-amino acid decarboxylase (AADC) enzyme and the transporter VMAT2 in the anterior pituitary, AtT20 and GH3 cells by immunofluorescence and western blot. Moreover, we investigated the production of DA from L-Dopa and its release in vitro. Then, we explored the effects of L-Dopa in the secretion of PRL from anterior pituitary fragments. We observed that the anterior pituitary, AtT20, and GH3 cells express both AADC and VMAT2. Next, we detected an increase in DA content after anterior pituitary fragments were incubated with L-Dopa. Also, the presence of L-Dopa increased DA levels in incubation media and reducedPRL secretion. Likewise, the content of cellular DA increased after AtT20 cells were incubated with L-Dopa. In addition, L-Dopa reduced CRH-stimulated ACTH release from these cells after the AADC activity was inhibited by NSD-1015. Moreover, DA formation from L-Dopa increased apoptosis and decreased proliferation. However, in the presence of NSD-1015, L-Dopa decreased apoptosis and increased proliferation rates. These results suggest that the anterior pituitary synthesizes DA from L-Dopa by AADC and this catecholamine can be released from this gland contributing to the control of PRL secretion. In addition, our results suggest that L-Dopa exerts directactions independently from its metabolization to DA.