Petrosal sinus catheterization in sheep. Development of a method for sampling hormonal output from the pituitary.

A relatively nontraumatic method has been developed to catheterize the petrosal sinus (PS) of sheep, via the internal jugular vein (IJV), using a percutaneous approach monitored by fluoroscopy. Preselection of suitable animals was facilitated by injecting radiopaque material through a cannula inserted into the deep facial vein to display the venous drainage from the pituitary. Further injections, via the same cannula, were later used to assist in the maneuvering of the catheter/wire guide combination as it passed up the IJV. To confirm catheter placement, plasma samples, collected simultaneously from PS and external jugular vein (EJV), were analyzed for growth hormone (GH). GH concentrations were consistently higher in the PS samples than in those found in the EJV, and more GH pulses were seen in PS samples than in the general circulation.