Appraising the nature of luteinizing hormone secretory events in men

We have appraised the nature of spontaneous luteinizing hormone (LH) secretory events in normal men by analyzing immunoactive LH concentrations in blood samples withdrawn at 5-min intervals for 24 h in eight healthy individuals. A novel discrete deconvolution algorithm was applied to determine apparent instantaneous LH secretory rates from these LH concentration series. These analyses unmasked unique attributes of spontaneous LH secretory events, which were represented as delimited momentary augmentations in endogenous LH secretory rates interspersed among intervals of relative secretory quiescence. For three different peak-detection thresholds (P = 0.02, = 0.01, and = 0.005), the frequency of LH secretory episodes was significantly greater than that of LH "pulses" judged from concentration data alone. Moreover, the total mass of LH released within discrete secretory episodes could account for approximately 90% of LH secreted during the day. This model of distinct, short-lived, burst-like secretion of LH has important implications for further investigations of the neuroendocrine regulation of gonadotropin secretion in humans.