Tetrapod-like hypothalamo-hypophysial portal system in the teleost Megalops cyprinoides (Broussonet).
A tetrapod-like hypothalamo-hypophysial portal system and a persistent bucco-hypophysial canal are present in Megalops cyprinoides. The complicated loops of the primary capillary plexus are seen on the ventral side of the infundibular floor and contact the perikarya of the nucleus lateralis tuberis and the preoptico-hypothalamo-neurohypophysial-neurosecretory tract. Although the pars intermedia receives part of its vascular supply from the pars distalis, the caudal hypophysial artery directly vascularizes the neurointermedia interface and forms the plexus intermedialis. The bucco-hypophysial canal is short and narrow in the fry and fingerlings but becomes long and tortuous as the fish grows. Megapopidae seem to be closer to the polypteriformids than to the teleosts. The possession of the pituitary portal system in megalopids may be a connecting link between the polypteriformids and other advanced teleosts.
Baskaran
G
G
Nesavedu, Nadu, India.
Sathyanesan
A G
AG
D000818:Animals; D001808:Blood Vessels / Q000033:anatomy & histology; D005399:Fishes / Q000033:anatomy & histology*; D007031:Hypothalamus / Q000033:anatomy & histology / Q000098:blood supply*; D010902:Pituitary Gland / Q000033:anatomy & histology / Q000098:blood supply*