| Popis: |
The reproductive cells of the pituitary, the gonadotropes, develop after e12.75 in mice and continue to differentiate and migrate throughout puberty. In response to physiological signals, these cells change in morphology to alter connections with other cells. Previous studies have indicated that gonadotropes have functional relationships in an interconnected, organized network. However, little work has been done to determine (1) what developmental cues are needed to organize this network, or (2) how this network functions to promote gonadotropin secretion. Activation of gonadotropin-releasing hormone receptors (GnRHRs) leads to an increase in intracellular calcium; therefore, this pathway can be used for visualizing the activation of gonadotropes. We have developed a novel system to analyze the gonadotrope network which will allow us to study the influence of physiological signals to this interconnected population. To visualize calcium signals specifically in gonadotropes, we created a line of Gonadotrope-GCaMP mice using Gnrhr-driven Cre to express the GCaMP calcium indicator. For present studies, intact pituitary glands were taken from adult Gonadotrope-GCaMP mice (males and proestrous females). Whole pituitaries were mounted in a chamber, and gonadotrope network responses to GnRH (1 or 5nM, at least 4 pituitaries/dose) were recorded using confocal microscopy. Calcium signals from an average of 177 ± 8 gonadotropes per pituitary were analyzed. MATLAB software was used to quantify network connections of gonadotropes for each treatment. Correlation coefficients were determined by their patterns of calcium signaling. Gonadotrope connectivity increases following GnRH stimulation in a dose-dependent manner in female pituitaries (17% following 1nM GnRH, p Using a novel gonadotrope-specific calcium indicator mouse model, we have shown GnRH-mediated changes in gonadotrope network connectivity in the intact mouse pituitary. Future studies in our lab will determine how other physiological signals are involved in development and/or maintenance of this coordinated activation. Presentation: Monday, June 13, 2022 12:30 p.m. - 2:30 p.m. |
