A frequency of growth hormone secretion associated with catch-up growth in the rat detected by time domain (Box-Jenkins) analysis.
A time domain technique has been applied to the analysis of temporal patterns of GH concentrations determined at 15 min intervals for 24 h in rats undergoing catch-up growth after a fast and in controls. Three tests were performed on the data. The first compared the autocorrelation functions (ACF's) and partial autocorrelation functions (PACF's) of the series of the GH measurements for the two groups. The second determined whether the model which best fit the control group removed all the regular behavior from the fasted group. The third test, which was similar to the second, was carried out with the assumption that the behavior of both groups is best conceptualized as a binary pattern of periods in which GH is either secreted or not. In the first test the ACF's and PACF's indicated that both groups have a memory of 15 min and a cycle(s) with a periodic interval in the range of 75 to 105 min. There was an indication of a cycle with a periodic interval of 180 to 210 min in the fasted group. The second test confirmed that the cycle was present in only the fasted rats. The third test confirmed the result of the second test. The findings demonstrate the usefulness of time domain analysis in determining periodic behavior of GH secretion in the rat. We conclude that a frequency of GH secretion with a periodic interval of approximately 195 min is superimposed on normal basal rhythms of GH secretion during catch-up growth following a fast in rats.
Mosier
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HD
Department of Pediatrics, University of California, Irvine 92717.
Catalano
R A
RA
Serxner
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S
Mosier
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CE
Jansons
R A
RA
D000818:Animals; D005215:Fasting; D005502:Food; D006128:Growth; D013006:Growth Hormone / Q000378:metabolism*; D008297:Male; D008433:Mathematics; D008954:Models, Biological; D051381:Rats; D013997:Time Factors
D013006:Growth Hormone