AVP and Hypocalcemia: Before embarking on an in vivo assessment of the efficacy of the calcilytic NPS 2143 in rectifying the Nuf mouse hypocalcemia, we used first an in vitro functional assay to determine whether NPS 2143 may normalize the gain-of-function associated with the Nuf Leu723Gln mutation, because some TMD-located ADH-associated CaSR mutations have been reported to be unresponsive or partially responsive to calcilytic drugs (19, –, 22, 25).