THE CELLULAR STRUCTURE OF THE LEYDIG ORGAN IN THE SHARK,ETMOPTERUS SPINAX(L.)

Abstract

In Etmopterus spinax, a small deep water shark, the predominating lymphomyeloid tissue is the so called Leydig organ. This consists of bone marrow-like tissue situated between the muscularis and the mucosa of the esophagus. Examination by light and electron microscopy shows that the Leydig organ produces large numbers of granulocytes and lymphocytes. Two main types of granulocytes occur, tentatively called heterophilic and eosinophilic. The heterophilic cells may be subdivided into three types which differ in the ultrastructure of the granules. Cells structurally resembling mammalian plasma cells are common. The presence of these cells indicates that the tissue is part of the shark immune system.

Aggregation of the smooth muscle cells found in certain hemopoietic organs and tissues of the stingray, Dasyatis akajei (Elasmobranchii, Chondrichthyes).

“…Nearly identical structures had already been long recognized as "Muskelspiralen" in the Leydig organ of the skates, Raja clavata and Try gon paStinaca (KULTSCHITZKY, 1911). Since KULTSCHITZKY'S study, much attention has been paid to the structures of the hemopoietic organs of the elasmobranchs (BOLTON, 1927;FANGE, 1968;FANGE and MATTISON, 1981;ZAPATA, 1981;FANGE, 1982, FANGE andPULSFORD, 1983;PULSFORD et al, 1984), but further light and electron microscopic studies on such structures have been lacking. Recently, using the stingray, we have demonstrated the Hassall-like structure not only in the hemopoietic organs but also in the choroid plexus of the diencephalon and connective tissue of the hypophysis.…”

“…This finding by KuLTScHI-TZKY (1911) on the Leydig organ of the skates is thus confirmed by the present study. However, such muscular structures occurring in the hemopoietic organs and loose connective tissues of batoids (skates and rays) have not been reported in the selachii (sharks) (FANGE and MATTISON,1981;MATTISON and FANGE, 1982;FANGE and PULSFORD, 1983;HoNMA et al, 1984;PULSFORD et al, 1984).…”

Untitled

“…Walsh and Luer (2004) later studied the histology of the epigonal organ and described the blood cells. Blood cells were orginated from the spleen and thymus as in other vertebrates but included unique organ associated with gonads (epigonal organ) and oesophagus (leyding organ) (Mattısson and Fänge, 1982;Walsh and Luer, 2004).…”

<b>Desenvolvimento embrionário dos órgãos linfoides do Tubarão-azul, <i>Prionace glauca</i> (Linnaeus, 1758), Elasmobranchii, Carcharhiniformes</b>

“…Segundo Mattson e Fänge (1982), o órgão de Leydig, é constituído de duas massas esbranquiçadas nas regiões dorsal e ventral do esôfago (MATTSON;FÄNGE, 1982). Tubarões das espécies Prionace glauca e Ginglymostoma cirratum têm um órgão de Leydig ausente ou muito pequeno (HAMLETT, 1999).…”

“…Estes órgãos são responsáveis pela função hematopoiética nos elasmobrânquios (FANGE;MATTISSON, 1981).…”