Effects of hypo- and hyperthyroidism on neuropeptide glutamic acid-isoleucine (NEI) in brain regions related to reproduction.

AYALA C; SOAJE M; VALDEZ SR; CARREÑO NB; JAHN GA; CELIS ME

Huerta Grande, Cordoba

Congreso; IRCN, First joint meeting of the Argentine Society of neurociences (SAN) and the Argentine Workshop in Neurociences (TAN).; 2009

NEI is a peptide derived from ppMCH that is capable of regulating the release of TSH and LH. Aim: To analyze if hypo- or hyperthyroidism can modify the content of NEl at different stages of the rat estral cycle, late pregnancy (day 19: G 19 and 21: G21) and early lactation (postpartum day 2: 12), in brain areas related to reproduction. Methods: Female Wistar rats weighing between 180 and 250 g were divided into control (C) and treated (T) groups. Hypo- and hyperthyroidism were induced with PTU and T 4, respectively. The studied brain areas were OVL T + A VPV (vascular organ of the lamina terminalis + anteroventral periventricular nucleus), POA (preoptic area), HLA (lateral hypothalamic area), Zl (zona incerta), PeN (periventricular nucleus), ME + Arc (median eminence + arcuate nucleus) and PP (posterior pituitary). NEI concentrations in samples were assessed by RIA. Results: Cycling females: OVLT +AVPV: the differences were observed in T, with the highest values found in T4 P12. POA (area related to sexual behaviour): the lowest values were for PTU and T4 P19h. HLA, higher concentration of NEl in C E 12 that decreased in T. Zl: the pattern between C and PTU was very similar with lower values in the latter; the peptide was hardly modified in T4. No differences in C and T were observed for PeN, and were minimal in ME +Arc. PP: there was a significant increase in T E 12h. Pregnant females: A significant increase of NEI was observed in pregnant rats: in OVLT + AVPV were found in T4 G 19 compared to PTU, in T4 G21 compared to C and PTU, and in C L2 compared to all other groups; in POA, in P11J G21 compared to C and T 4; the content of NEl in HLA for C L2 was greater than in T; increases in Zl were observed in C and T4 G19 compared to PTU, in T4 G21 compared to C and PTU, and in L2 compared to all other groups; in POA, in PTU G21 compared to C and T4; the content of NEI in )-llA for C L2 was greater than in T; increases in ZI were observed in C and T4 G 19 compared to PTU, and in C L2 compared to T; PeN showed increases in T G2 1 compared to C; increases in ME+ Arc were found in C L2 compared to PTU and T4 L2; and in PP, there were increases in T4 G21 compared to C and PTU. Conclusion: The content of NEI in different brain regions related to reproduction is modified by hypo or hyperthyroidism in cycling, pregnant and early lactation females.