Learn More
High creatine kinase (CK) activity (16.5 +/- 7.6 IU/mg) is present in trout spermatozoa. In order to partly characterize the CK isozyme predominantly present in sperm and to study the expression of this protein in spermatogenesis, we purified to homogeneity a CK (s-CK) from trout sperm, by nitrogen cavitation followed by two chromatography steps(More)
Interaction between growth and reproduction occurs in many vertebrates and is particularly obvious at certain stages of the life cycle in fish. Endocrine interactions between the gonadotropic axis and the somatotropic axis are described, the potential role of GH being emphasised. A comparative analysis of these phenomena in mammals, amphibians and fish,(More)
The function of the cysteine-containing spermatidal proteins and of protamine in the packaging and stabilization of chromatin during ram spermiogenesis was investigated. Extractions of the histones and spermatidal proteins from the nonround spermatid nuclei decreases the nuclear stability (sonication resistance), decondenses the chromatin, and reduces the(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)
  • M Loir
  • 1990
Somatic cells (interstitial cells and Sertoli cells) were prepared either as single cells or in clusters, from spermatogenic and mature trout testes, according to Loir (1988), and cultured for 10-14 days. Sertoli cells are 3 beta-HSD negative when prepared from testes resuming spermatogenesis and from mature testes, but they are 3 beta-HSD positive in(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)
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)
  • M Loir
  • 1999
At the present time, in spite of recent advances, knowledge about the factors regulating germ cell proliferation in the teleost testis is limited. This study was designed to investigate, in vitro, the ability of various hormones, growth factors, and steroids to influence the proliferation of trout spermatogonia (Go) present in mixed cultures of somatic and(More)
Growth hormone (GH) binding to testis tissue and GH action on trout testicular cells were studied in vitro. Labeled salmon GH (sGH) was able to bind to a trout testis membrane preparation. Binding sites showed high affinity (Ka = 1-2 x 10(9) M-1) and low capacity (11 fmol/g fresh tissue) for 125I-sGH. Salmon GH and bovine GH, but not salmon gonadotropin,(More)
  • M Loir
  • 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)