Background:

CGP71683 hydrochloride is a competitive neuropeptide Y5 receptor antagonist with a Ki of 1.3 nM, and shows no obvious activity at Y1 receptor (Ki, >4000 nM) and Y2 receptor (Ki, 200 nM) in cell membranes.
CGP71683 hydrochloride is a competitive neuropeptide Y5 receptor antagonist with a Ki of 1.3 nM, and shows no obvious activity at Y1 receptor (Ki, >4000 nM) and Y2 receptor (Ki, 200 nM) in cell membranes[1].

CGP71683 (15 nmol/rat, icv, twice daily) shows anorexigenic effect, reducing food intake and bady weight of fed rats. CGP71683 causes 3-times higher serum total T4 and 37% increase in free T4 in the fasted rats than in the fasted controls rats[2].

Reference：
[1]. Lecklin A, et al. Receptor subtypes Y1 and Y5 mediate neuropeptide Y induced feeding in the guinea-pig. Br J Pharmacol. 2002 Apr;135(8):2029-37.
[2]. Costa-e-Sousa RH, et al. Central NPY-Y5 receptors activation plays a major role in fasting-induced pituitary-thyroid axis suppression in adult rat. Regul Pept. 2011 Nov 10;171(1-3):43-7.