Figure 3.

Loss of either Arrb1^−/− or Arrb2^−/− significantly diminishes Kp-54–triggered LH secretion. Serum LH levels were measured by RIA. Mice were either left untreated or treated with saline or 100 nmol Kp-54/kg body weight. Sixty minutes later, blood was collected and serum prepared. Kp-54–triggered LH levels in Arrb1^−/− (A) and Arrb2^−/− (B) mice were significantly higher (P < .001) than levels from their respective untreated and saline-treated controls. Kp-54–triggered LH levels were significantly lower (P < .001) in Arrb1^−/− (A) and Arrb2^−/− (B) mice compared with their respective WT littermate controls. Only male mice were used to preclude the effects of estrous cycle variation on GnRH secretion in females. Error bars represent SEM.