Pulsatile growth hormone release in the rat: failure to demonstrate a correlation with sleep phases.
Concurrent 5-hour profiles of growth hormone (GH) secretion and sleep phases were obtained in 7 rats chronically implanted with right atrial cannulae, and electroencephalographic electromyographic, and electroculographic electrodes. Hormone profiles confirmed pulsatile secretion of GH. Secretory GH episodes occurred every 3 to 4 hours and peaks generally exceeded 100 ng/ml, and, in 14 of the 21 troughs recorded, GH was unmeasurable (less than 1 ng/ml). The comparison of hormone profiles and concurrent sleep patterns excluded a temporal relationship between episodic GH secretion and sleep cycles, while scattergrams of hormone values plotted against preceding sleep phase durations also failed to demonstrate a relationship.
D000818:Animals; D001921:Brain / Q000502:physiology; D004567:Electrodes, Implanted; D004594:Electrophysiology; D013006:Growth Hormone / Q000502:physiology*; D006321:Heart / Q000502:physiology; D008297:Male; D009132:Muscles / Q000502:physiology; D051381:Rats; D012894:Sleep Stages / Q000502:physiology*; D013997:Time Factors
D013006:Growth Hormone