A quantitative study of the pulsatile parameters of CRH-41 secretion in unanesthetized free-moving rats

Having recently improved the sensitivity of the RIA CRH-41 measurements in perfusates from push-pull cannulas implanted in the rat median eminence, we explored quantitatively the pulsatile parameters of the CRH-41 measured with this technique at 2.5 or 5 min intervals in a series of unanesthetized male rats under basal conditions. The data were analysed by computer using 4 algorithms, i.e. Santen & Bardin, Ultra, Pulsar and Periodogram. Under a basal mean secretion rate of 15.5 pg CRH-41/15 min, the pulsatile pattern of CRH-41 release was statistically assessed with the 4 methods, with a mean pulse frequency of 3.1 c/h, pulse length of 11.6 min and a peak amplitude above mean levels of 4 pg. The respective advantages of the 4 algorithms and the physiological relevance of the neurohormone's pulsatility are discussed.