Light microscopic study of the hypophyseal angioarchitecture in the rabbit

Abstract

This study describes the hypophyseal angioarchitecture found in 79 adult New Zealand white rabbits. The pituitary glands and attached hypothalami were removed and carefully processed following routine histological methods, and the vascular organization was studied by light microscopy. Whole mounts of the pituitary median eminence complex were prepared and studied with a binocular dissecting microscope employing transmitted and epi-illumination. Arterial blood was found to be directed primarily to the neurohypophysis by the superior hypophyseal artery (SHA) and the inferior hypophyseal artery (IHA). A direct arterial blood supply was found to the adenohypophysis, but was limited solely to the pars intermedia by branches of the anterior hypophyseal artery (AHA) and the IHA. Capillaries of the pars intermedia were subdivided into an intermediate and a superficial plexus. The superficial plexus was situated between the intermediate plexus and the capillaries of the infundibular process. Capillaries of the superficial plexus did not form anastomoses between themselves, but ramified into the intermediate plexus to form a dense network of anastomosing capillaries that were continuous with capillaries of the pars distalis. A direct arterial blood supply was found only to the superficial plexus.

Hypophyseal angioarchitecture of common tree shrew (Tupaia glis) revealed by scanning electron microscopy study of vascular corrosion casts

“…The PI in the tree shrew is well demonstrated and highly vascularized with radiating capillaries connecting with the capillary network in the IP as well as receiving branches directly from the IHA. This is much different from the PI in the rat (Murakami et al, 1985) and rabbit (Foster and Boyd, 1989) which have a greatly reduced number of blood vessels even though the capillaries in the PI organize into superficial and deep plexi.…”

“…This is much different from the PI in the rat (Murakami et al, 1985) and rabbit (Foster and Boyd, 1989) which have a greatly reduced number of blood vessels even though the capillaries in the PI organize into superficial and deep plexi.…”

“…In the rabbit, however, the blood from the PD drains into a few lateral hypophyseal veins before proceeding into the cavernous sinus. The capillaries in the PI and IP drain into separate venules before joining to become confluent pituitary venules and drain into the cavernous sinus (Foster and Boyd, 1989).…”