Methods for the Adrenalectomy of the European Eel (Anguilla Anguilla L.)

Abstract

This communication presents methods for the removal of the adrenocortical tissue of the eel (Anguilla anguilla L.). Therefore the anatomy of that area is first described. For a general account of the vascular system see Mott (1950).The right posterior cardinal vein (Pl. 1 a) runs from the posterior part of the kidney to join the right anterior cardinal vein at the level of the sinus venosus, which it enters, together with the jugular vein by a common vessel, the right ductus Cuvieri. Variations include the separate entry of the right anterior cardinal vein and the right posterior cardinal vein into the sinus venosus. The vein from the swim-bladder may enter the sinus venosus either as a separate vessel or be received by the right posterior cardinal vein, just outside the pericardium. The left posterior cardinal vein (Pl. 1b) is small and sometimes defective. It arises from the kidney more anteriorly than the right posterior cardinal vein on the opposite side, joining the left anterior cardinal vein, leading to the left ductus Cuvieri which receives the jugular vein and a small vessel from the left anterior cardinal vein. There are small anasto¬ mosing vessels between the right and left posterior cardinal veins, a more prominent one (PI. lc) occurs at the level of the posterior limit of the liver.The head-kidney on the right side commences just posterior to the junction of the right posterior cardinal vein and swim-bladder vein and at about a similar distance posterior to the sinus venosus when the swim-bladder vein enters the heart separately. The head-kidney extends posteriorly to the caudal kidney. The right head-kidney is readily removed from the right posterior cardinal vein by blunt dissection. In contrast, the left head-kidney is intimately associated with the left posterior cardinal vein, extending from a level just posterior to the left ductus Cuvieri, posteriorly to the caudal kidney. Adrenocortical tissue is found only in the anterior part of the headkidney and in the walls of the left and right posterior cardinal veins (PI. 2). Adreno¬ cortical tissue more frequently abuts against the right head-kidney, but is contained within the left head-kidney.Adrenalectomy of teleost fish has not been previously described because of the difficulties posed by the intimate connexion of the adrenal cortex with the headkidney and posterior cardinal veins. Etoh & Egami (1963) briefly mention, without details, the possibility of adrenalectomy of goldfish. We understand that the headkidney is sucked out by a cannula (C. Tachi, personal communication). This is a method of partial adrenalectomy as adrenocortical tissue would remain in the walls of the cardinal veins (Chester Jones, 1957). The following method of adrenalectomy in the eel has therefore been devised.Eels are anaesthetized with MS 222 (tricaine methanosulphate, Sandoz). A ventral

Studies on the Experimental Alteration of Water and Electrolyte Composition of the Eel (Anguilla Anguilla L.)

“…The methods were those described by Chester Jones, Henderson & Mosley (1964), venous replacement with artificial tubes being done in about half the animals. The results from the methods of venous replacement or removal showed no differences and are taken together.…”

Biogenesis of Corticosteroids in the European Eel Anguilla Anguilla L.

“…The eel is a convenient animal for incubation studies because the adrenocortical tissue is for the most part concentrated in the walls of the posterior cardinal veins (Chester Jones, Henderson & Mosley, 1964) though some may occur in the anterior cardinal veins. Thus, the conversion, in vitro, of potential steroid hormone precursors [4-14C]progesterone, [16-3H]pregnenolone, [l,2-3H]corticosterone and [l-14C]sodium acetate was investigated with special reference to the qualitative aspects of steroidogenesis, the possible biosynthetic pathways, and the presence or absence of 18-oxygenated steroid hormones, particularly aldosterone.…”

Sodium and Water Balance in the Cichlid Teleost, Tilapia Mossambica

“…The apparent change in permeability is consistent with observations made recently on the effects of hypophysectomy and prolactin or urine production in other teleosts. It has been shown both in Anguilla (Jones, Henderson & Butler, 1965) and in Funduluskansae (StaiAey & Flemming, 1966) that hypophysectomy reduces the rate of urine flow in fresh water. Both species can survive after hypophysectomy in fresh water although this is not true of many other fishes.…”