Fig. 1.17 
The effect of constant high levels of GnRH on gonadotrophin secretion. 
Data from a monkey with hypothalamic lesions (causing GnRH deficit) show that continuous infusions of GnRH suppress LH and FSH releas while pulsatile injections restore it. Similar suppressive actions can be exerted by long-acting. ‘super agonist’ doses of GnRH. Modified from Belchez et al ( 1978); by courtesy of the MAS.