Thyrotropin-Releasing Hormone Precursor Gene Knocking Down Impedes Melanocortin-Induced Hypertension in Rats

MARÍA S. LANDA; SILVIA I. GARCÍA; MARIANO L. SCHUMAN; AZUCENA L. ALVAREZ; SAMUEL FINKIELMAN; CARLOS J. PIROLA

HYPERTENSION

American Heart Association.

Lugar: Dallas, TX; Año: 2008 vol. 52 p. 1 - 2

0194-911X

Leptin effects include increases in sympathetic activity and inhibition of the starvation-induced suppression of thyroid hormones apparently by upregulating prepro-TRH gene expression.Then, leptin can increase the MC4R ligand (-melanocytestimulating hormone) production to regulate TRH expression.Furthermore, we have shown that ICV leptin injections induce a pressor effect that is avoided by prepro-TRH AS pretreatment. Hence, we proposed that melanocortin activity may raise ABP through TRH activation, and we report here that, in Wistar rats, the MCR4 agonist (-melanocyte-stimulating hormone agonist [MTII])?induced elevation of ABP can be blocked by 24-hour ICV pretreatment with prepro-TRH ASIn conclusion, we show that the melanocortin 3 and 4 agonist induced hypertension only in the presence of an intact hypotha-lamic TRH system; thus, we propose that an activation of the axis leptin-melanocortin-TRH might explain increases of ABP in this genetic model of hypertension.