Metabolic changes associated with pigmentary effector activity and pituitary removal in Xenopus lævis —I. Respiratory exchange

There are various indications of connection between the pituitary gland and basal metabolism; between the pituitary gland and ovarian activity; and between ovarian activity and calcium metabolism. Progress in the study of the relationship of the pituitary to metabolism had been held back by the technical difficulties of mammalian hypophysectomy. By a method described by Hogben, the removal of the pituitary gland as a whole or of the anterior lobe alone can be performed without great difficulty and with great rapidity in adult Amphibia. The animals survive the operation indefinitely. The same author has shown that the posterior lobe of the pituitary gland plays a predominent rôle in controlling colour change, and latterly, in collaboration with Slome, has given strong indications that the anaterior lobe of the gland also plays a part in determining the pigmentary effector activity of the South African clawed toad,Xenopus lævis (Daudin). These circumstances have suggested the advisability of parallel investigation of the effects of the total or partial removal of the pituitary gland and the influence of normal agencies affecting colour change (and thereby pituitary activity) upon the metabolism of this species. The present communication is connected with two issues:— 1. Total respiratory exchange in air. 2. Dermal oxygen consumption in water. The conditions affecting colour response, and the time relations of colour response, etc., inXenopus lævis , have been recorded thoroughly (Slome and Hogben). These authors have shown that photic stimuli are the predominant natural agencies, the condition for pallor being that the field of vision is occupied by a light-scattering surface, and the condition for darkening that the field of vision is occupied by a light-absorbing surface. Eyeless animals are intermediate in hue but the condition of eyeless animals or animals kept in the dark has been shown to be physiologically different from intermediat animals in a stage of transition from the white background to the black blackground response andvice versa . This conclusion, based on an analysis of the time curve, receives some confirmation from the data hereafter recorded.