V. Casimiri et al., PHENYLETHANOLAMINE-N-METHYL TRANSFERASE AND CATECHOL-O-METHYL TRANSFERASE-ACTIVITY IN RAT UTERUS - CYCLIC AND STEROID-INDUCED CHANGES, Acta obstetricia et gynecologica Scandinavica, 72(8), 1993, pp. 606-610
Purpose. The activity of phenylethanolamine-N-methyl-transferase (PNMT
) and catechol-O-methyl-transferase (COMT) was studied in uterine homo
genates from adult female Wistar rats with normal cycles and that had
been ovariectomized, adrenalectomized, and steroid-treated. Results. A
ctivities of the two enzymes changed significantly during the normal e
strus cycle. Both peaked during metestrus, with COMT showing a seconda
ry peak of activity at proestrus. Progesterone treatment significantly
increased and estradiol decreased PNMT activity in comparison to untr
eated controls. Hydrocortisone administration had no effect on uterine
PNMT activity. COMT activity was not affected significantly by any of
the steroid treatments. Conclusion. The data confirm that uterine tis
sues possess the enzymatic machinery to synthesize epinephrine from no
repinephrine, and suggest the activity of this pathway may be mediated
by variations in the sex hormone environment of the uterus.