Functional Characterization of Genetically Labeled Gonadotropes

Gonadotropes are crucial in the control of reproduction but difficult to isolate for functional analysis due to their scattered distribution in the anterior pituitary gland. We devised a binary genetic approach, and describe a new mouse model that allows visualization and manipulation of gonadotrope cells. Using gene targeting in embryonic stem cells, we generated mice in which Cre recombinase is coexpressed with the GnRH receptor, which is expressed in gonadotrope cells. We show that we can direct Cre-mediated recombination of a yellow fluorescent protein reporter allele specifically in gonadotropes within the anterior pituitary of these knock-in mice. More than 99% of gonadotropin-containing cells were labeled by yellow fluorescent protein fluorescence and readily identifiable in dissociated pituitary cell culture, allowing potentially unbiased sampling from the gonadotrope population. Using electrophysiology, calcium imaging, and the study of secretion on the single-cell level, the functional propertie...