Maurice Loir

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In this paper we present the state of knowledge on cell-cell interactions in the testis of two groups of anamniote vertebrates--teleosts and elasmobranchs--which include most fish. In these fish, the structural organization of the testis differs fundamentally from that which characterizes amniotes in which the germinal tissue is located in tubules open at(More)
The major non-vascular cell types present in the interstitial compartment in trout testes have been ultrastructurally characterized and cell changes in the course of the two first reproductive cycles have been studied. Three major cell types are always present fibroblasts, myoid cells and Leydig cells. Their structure varies with the maturational stage of(More)
Changes in growth hormone (GH) receptivity in the testis during the reproductive cycle were studied in rainbow trout (Oncorhynchus mykiss). This necessitated setting up a method to characterize GH receptors (GH-R) in crude testis homogenate. Binding of radiolabeled recombinant rainbow trout GH (125I-rtGH) to crude testis preparation was dependent on(More)
Live trout spermatozoa initiate flagellar motility for a short period of time (30 s at 18 degrees C), during which their mean beat frequency (BF) decreases steadily from 60 to 20 Hz; motility then stops abruptly. When demembranated, the motility of axonemes lasts much longer, up to 20 min, with high beat frequency, provided that ATP (millimolar(More)
The effect of a long-term adaptation of rainbow trout to 8 and 18°C combined with a corn oil-or a fish oil-supplemented diet on the characteristics of the spermatozoan plasma membrane was investigated. The experiment lasted up to 22 mon during which spermatozoa were collected from the mature males. Spermatozoan plasma membranes were isolated by nitrogen(More)
Les interactions entre les fonctions de croissance et de reproduction mises en évidence chez de nombreux vertébrés, sont particulièrement aigües à certaines étapes du cycle vital des poissons. Nous décrivons les interactions endocrines existant entre les axes somatrope et gonadotrope en insistant sur le rôle joué par l'hormone de croissance (GH). L'analyse(More)
  • M Loir
  • Molecular reproduction and development
  • 1999
Prerequisites of developing in vitro studies for a better understanding of the control mechanisms underlying the proliferation and differentiation of spermatogonia (Go) in the teleost testis are: (1) to be able to identify the different types of Go; (2) to maintain in culture the structural relationships occurring in situ between the various testicular cell(More)