Parasitism in Relation to the Pituitary of Ophicephalus punctatus and Barbus stigma

Abstract

THE interrelationship between the pituitary and the target organs is, more or less, well known. According to Kerr¹, the occurrence of the plerocercoid stage of a tapeworm (Ligula intestinalis) in the body cavity of the roach Leuciscus rutilus (Flem.) results in a marked regression of the gonads and in the reduction of the basophils in the middle glandular portion of the pituitary. In the case of the stickle-back (Gasterosteus aculeatus L.), however, infected with Schistocephalus solidus, no difference between the normal and the parasitized fish could be detected and the influence of Schistocephalus solidus on G. aculeatus is less manifest. The functional relationship between the pituitary and the gonads in fishes has been determined by the injection of pituitary extracts² or by hypophysectomy³. Recent studies on the correlation of the cyclical changes in the pituitary and in the gonad of Cyprinus carpio⁴, Carassius auratus⁴ and Rhodeus amarus⁵ also lend support to the existence of the stipulated relationship.