Inhibition of the stimulatory effect of ACTH on adrenal and ovarian blood flow by indomethacin in the dog.

In anoestrous dogs heated thermocouples were inserted into one of the adrenals and ovaries. The basal adrenal and ovarian blood flow was recorded and enhanced by 1.2, 2.5 or 5.0 micrograms/kg of intravenous ACTH before and after the intravenous administration of 20 or 50 mg/kg of indomethacin. Indomethacin, depending on the dose and on the time elapsing after its administration inhibited the enhancing effect of ACTH on adrenal and ovarian blood flow. Since indomethacin is a specific inhibitor of prostaglandin synthesis it has been suggested that prostaglandins act as mediators in the vasodilatation elicited by ACTH in the canine adrenal and ovary.