The objective of this proposal is to determine the extent and mechanisms by which the information provided by physiological pulses versus steady state gonadotropin stimulation controls the function and developmental state of ovarian tissue. This objective will be approached through use of a custom designed, unique, computer-controlled, open loop, perifusional system with capabilities for on-line data acquisition, reduction and analysis. Ovarian tissues will be obtained primarily from immature and adult rats, bu also on occasion from sheep. In particular, attempts will be made to determine the extent to which ovarian cells exhibit oscillatory activity, respond differentially to pulsatile gonadotropic signals as distinct from fixed concentrations, and involve desensitization in determining the patterns of response to the pulsatile signals. In addition attempts will be made to determine the role of agents known to act on the ovary in modulating the observed responses to pulsatile gonadotropins, and to determine the extent to which products of stimulated ovarian cells affect or control the function of other ovarian cells. Response parameters to be examined include transient changes in extracellular ions (using tubular flow-through ion-selective electrodes); cAMP and steroids (by ELISA, IRMA and RIA); membrane LH receptor (by radioligand receptor assay); and cellular interactions as assessed morphologically (by light microscopy and electron microscopy using scanning and transmission modes).