Melatonin Concentrations in the Gastrointestinal Tissues of Fetal Bovids

Autor: R. R. Hacker, G. A. Bubenik, G. M. Brown, L. Bartoš
Rok vydání: 2000
Předmět:
Zdroj: Acta Veterinaria Brno, Vol 69, Iss 3, Pp 177-182 (2000)
ISSN: 1801-7576
0001-7213
DOI: 10.2754/avb200069030177
Popis: Bubenik G. A., G.M. Brown, R.R. Hacker, L. Barto‰: Melatonin Concentrations in the Gastrointestinal Tissues of Bovine Fetuses. Acta Vet. Brno 2000, 69: 177–182. Day-time tissue levels of melatonin were determined in the rumen, reticulum, omasum, abomasum, jejunum, ileum and colon of cow fetuses of both sexes. The total body length of the fetuses was 14 to 53 cm which corresponds to the first half of pregnancy; the approximate gestation age was 85-150 days. The data were divided into five equal groups according to fetal length. Average total melatonin concentrations (34.0 to 49.8 pg/g) did not differ greatly between the developmental stages but nevertheless a positive correlation (r s = 0.35, P < 0.001) was established between melatonin levels and fetal length. Significantly higher concentrations of melatonin (P < 0.001) were found in the male GIT. Finally, colon tissues exhibited higher concentrations of melatonin than any other GIT segment. As the average day-time values in fetal GIT (30.2 pg/g) were substantially lower than GIT levels found in adult cows (50-270 pg/g), it could be hypothesized that melatonin levels in the fetal GIT are derived from the maternal circulation. However, higher melatonin levels in older fetuses, the detection of higher levels in males and substantially higher levels of melatonin in the fetal GIT as compared to blood levels in adult cows, may indicate either an independent fetal production of GIT melatonin or the capacity of fetal GIT to concentrate melatonin derived from the maternal circulation. In view of these discrepancies it can be only concluded that the origin of melatonin in the bovine fetal GIT is at present unknown. The significantly higher concentration of melatonin found in the colon (P < 0.05) may be related to the presence of meconium detected in most fetuses in that GIT segment. This finding may indicate that melatonin has a physiological function in the fetal digestive system.
Databáze: OpenAIRE
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