C. Ribelayga et al., ONTOGENY OF HYDROXYINDOLE-O-METHYLTRANSFERASE GENE-EXPRESSION AND ACTIVITY IN THE RAT PINEAL-GLAND, Developmental brain research, 110(2), 1998, pp. 235-239
Postnatal development of hydroxyindole-O-methyltransferase (HIOMT) mRN
A expression, HIOMT activity and melatonin content was investigated in
the rat pineal gland from birth to adulthood (62-day old). For each a
ge, animals were sacrificed at two different time-points: midday and m
idnight. HIOMT mRNA was first detectable one day after birth and maxim
al diurnal levels were reached at the end of the first week. A 2-fold
nocturnal increase appeared significantly 11 days after birth. HIOMT a
ctivity was detectable from 5 days of life and significant day/night v
ariations did not appear before 21 days after birth. Appearance of mel
atonin synthesis and rhythm followed that of HIOMT mRNA. The 10-day de
lay observed between the appearance of the nocturnal increase in HIOMT
activity and expression is discussed in term of differential regulati
on of both HIOMT mRNA expression and HIOMT activity. (C) 1998 Elsevier
Science B.V. All rights reserved.