A cytological study on the structure of the pituitary gland of Monopterus albus (Zuiew)

Abstract

The pituitary gland of the ricefield eel, Monopterus albus is made up of the neurohypophysis, which form the central core, and the adenohypophysis, which completely surrounds the former except at the infundibular connection. Pituitaries, in longitudinal and transverse serial sections, lave been studied by standard histological and histochemical techniques including Periodic acid-Schiff(PAS)/Celestine blue (CB)/Orange Gy- (OG), Herlant's tetrachrome (HT), Lead haematoxylin (PbH)/PAS, Aldehyde Fuchsin (AF), Luxol fast blue (LFB)/PAS/OG, Alcian blue (AB, pH 0.2 and pH 3.0)/PAS/OG, and Aldehyde Thionine (AT)/PAS/LFB. Seven tinctorial cell types are distinguishable in the adenohypophysis: the erythrosiniphilic and PbH-positive amphiphil (Type 1); erythrosinophilic acidophil (Type 2); orangeophilic acidophil (Type 3) ; PbH-positive acidophil (Type 4) ; very intensively AF-positive, AB-positive and AT-positive basophil (Type 5) ; weakly AF-positive, AB-positive and AT-positive basophil (Type 6) ; strongly AF-positive, AB-positive and AT-positive (Type 7). Chromophobes which show no affinity for any of the above stains are also found. The neurohypophysis shows extensive interdigitations and staining with AF, AB and AT indicates that the neurosecretion is concentrated towards the distal end of the neurohypophysis. Blood capillaries are found in abundance both in the adenohypophysis and in the neurohypophysis. The present report is the first in the series of studies on the role of pituitary in natural sex reversal in Monopterus and provides the basic information on the pituitary cytology and structure for further experimental and biochemical investigations which are reported separately.