Poyser N L
J Reprod Fertil. 1979 Jul;56(2):559-65. doi: 10.1530/jrf.0.0560559.
Intrauterine, but not systemic, administration of actinomycin D on Day 10 increased oestrous cycle length in guinea-pigs. Peripheral plasma progesterone levels remained elevated during these lengthened cycles presumably because luteal life-span had been extended. Prostaglandin (PG) F-2 alpha production in vitro, on Day 15, by the uterus of guinea-pigs which had received intrauterine actinomycin D was much lower than control values. This decrease in PG production was not due to lack of precursor, increased metabolism, re-direction of synthesis towards PGE-2, or a direct inhibition by actinomycin D of the conversion of arachidonic acid to PGs. The effects of actinomycin D treatment were not reversed by oestradiol. It is proposed that actinomycin D prevents the increase in uterine PG synthetase levels that normally takes place after Day 11, thereby reducing uterine PGF-2 alpha synthesis and output in vivo, and resulting in luteal maintenance and longer oestrous cycles.
在第10天对豚鼠进行子宫内而非全身给予放线菌素D，可延长其发情周期长度。在这些延长的周期中，外周血浆孕酮水平持续升高，推测这是因为黄体寿命延长。在第15天，接受子宫内放线菌素D的豚鼠子宫体外产生的前列腺素（PG）F-2α远低于对照值。PG产生的这种降低并非由于前体缺乏、代谢增加、合成转向PGE-2，也不是由于放线菌素D对花生四烯酸转化为PG的直接抑制。放线菌素D处理的效果不会被雌二醇逆转。有人提出，放线菌素D可阻止通常在第11天后发生的子宫PG合成酶水平的升高，从而在体内减少子宫PGF-2α的合成和输出，导致黄体维持和更长的发情周期。
