TY - JOUR
T1 - Concurrent determination of enzymatic activities and substrate concentrations in the melatonin synthetic pathway within the same rat pineal gland
AU - Champney, Thomas H.
AU - Holtorf, A. P.
AU - Steger, R. W.
AU - Reiter, R. J.
PY - 1984
Y1 - 1984
N2 - This study details the procedures involved in measuring a number of the components of indole metabolism within the pineal gland. Tryptophan, 5‐hydroxytryptophan, serotonin, N‐acetylserotonin, melatonin, 5‐hydroxyindoleacetic acid, N‐acetyltransferase (NAT) activity, and hydroxyindole‐O‐methyltransferase activity were measured by a combination of three techniques, which included microassays, radioimmunoassay, and high‐performance liquid chromatography. Determination of the melatonin synthetic pathway components within the same gland reduces the number of animals needed for studies and allows correlations between these constituents to be calculated. Very high degrees of correlation (r=0.91−0.99) are seen between those compounds which exhibit significant rhythms (serotonin, NAT activity, N‐acetylserotonin, and melatonin) when group means are compared. When correlations are calculated on a per‐animal basis throughout the experiment, moderate to high degrees of correlation (r=0.57−0.79) are found among those components that exhibit rhythms. However, when correlations are determined on a per‐animal basis at each time point, no significant correlations are found. One hypothesis accounting for these differences may be that changes occur in indole metabolism within the same pineal gland over a period of a few minutes.
AB - This study details the procedures involved in measuring a number of the components of indole metabolism within the pineal gland. Tryptophan, 5‐hydroxytryptophan, serotonin, N‐acetylserotonin, melatonin, 5‐hydroxyindoleacetic acid, N‐acetyltransferase (NAT) activity, and hydroxyindole‐O‐methyltransferase activity were measured by a combination of three techniques, which included microassays, radioimmunoassay, and high‐performance liquid chromatography. Determination of the melatonin synthetic pathway components within the same gland reduces the number of animals needed for studies and allows correlations between these constituents to be calculated. Very high degrees of correlation (r=0.91−0.99) are seen between those compounds which exhibit significant rhythms (serotonin, NAT activity, N‐acetylserotonin, and melatonin) when group means are compared. When correlations are calculated on a per‐animal basis throughout the experiment, moderate to high degrees of correlation (r=0.57−0.79) are found among those components that exhibit rhythms. However, when correlations are determined on a per‐animal basis at each time point, no significant correlations are found. One hypothesis accounting for these differences may be that changes occur in indole metabolism within the same pineal gland over a period of a few minutes.
KW - indoleamines
KW - melatonin
KW - pineal
KW - rhythms
KW - techniques
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U2 - 10.1002/jnr.490110107
DO - 10.1002/jnr.490110107
M3 - Article
C2 - 6708134
AN - SCOPUS:0021325339
VL - 11
SP - 59
EP - 66
JO - Journal of Neuroscience Research
JF - Journal of Neuroscience Research
SN - 0360-4012
IS - 1
ER -