Adenylate cyclase activity in the uterine cervix of neonatal and immature mice: influence of oestradiol-17 beta.

The influence of long-term oestradiol stimulation on adenylate cyclase activity was investigated in homogenates from uterine cervices of neonatal (3-day-old) and immature (14-day-old) NMRI mice. A significant increase of enzyme activity, measured in the presence of fluoride ions (NaF), after oestradiol treatment was found in preparations from neonatal but not from those of immature female mice; this was irrespective of whether the enzyme activity was related to wet weight, amount of protein or DNA content. The enzyme activity was stimulated in vitro by NaF and 5-guanylylimidodiphosphate while isoprenalin, histamine, prolactin and oestradiol had no effect. These results indicated an age-related difference in the effects of oestradiol in the uterine cervix of the mouse.