Frederic Le Menn

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High levels of 11-ketotestosterone (11KT) were found (49 to 160 ng ml−1) in plasma of Siberian sturgeon females during the end of their reproductive cycle. These levels were measured either by specific radioimmunoassay, or both by specific radioimmunoassay and by UV absorption after HPLC (isocratic conditions, 33% methanol, 26% acetonitrile, 41% water). In(More)
A simple and rapid Enzyme Linked ImmunoSorbant Assay (ELISA) is described and validated for testosterone, estradiol, and 17,20β-dihydroxy-4-pregnen-3-one (17,20βP). A general procedure for preparation of the acetylcholinesterase labeled steroid is described which is applicable to any steroid. Use of acetylcholinesterase tracer increased the sensitivity of(More)
An immunohistochemical study of the sturgeon (Acipenser baeri) pituitary was undertaken using antisera directed against hormones from various classes of vertebrates, including the only pituitary hormone available from sturgeon, gonadotrophin. A positive reaction was obtained after application of antisera towards the following hormones 1–24 synthetic ACTH(More)
Female rainbow trout were exposed over their second reproductive cycle to a simulated natural photoperiod (control group) and to two accelerated photoperiod regimes (S9 and S6 groups). Early spawning was achieved in both accelerated groups, coupled, however, with a reduction of mean egg size. To investigate this reduction of egg size, circulating levels of(More)
Plasma kinetics of tritiated estradiol (E2) were studied in the Siberian sturgeonAcipenser baeri in order to explain the large amount of E2 found in plasma of 4, 5 and 10-year-old cultured males. This work presents two approaches. The first is based on a single ingestion of3H-labelled E2, which allowed us to plot model curves of resorption and elimination(More)
This paper presents a generic kinematic modeling approach for articulated multi-monocycle mobile robots. The formulation proposed to deduce the input/output velocity equations for such kinematic structures is an extension of the reciprocal screw based method of asymmetrical and constrained parallel mechanisms. The efficiency of this methodology for setting(More)
Changes in 17β-estradiol (E2), estrone (E1), testosterone (T), 11-ketotestosterone (11KT), and 17,20β-dihydroxy-4-pregnen-3-one (17,20β-P) levels were correlated to changes in gonadosomatic index (GSI), vitellogenin concentration (Vg), ovarian and testicular histology during the annual reproductive cycle of the red porgy, Pagrus pagrus. The production of(More)
Injections of 2.5 mg/kg of stellate sturgeon (Acipenser stellatusPall.) pituitary extract and 5 mg/kg of carp (Cyprinus carpioL.) pituitary extract in Siberian sturgeon (Acipenser baeriBrandt) females did not reveal significant differences in the effects of these preparations. There were no differences in the percentage of females that responded by(More)
The GnRH system was studied in the brain of the sole by immunocytochemistry (peroxidase-antiperoxidase method) (PAP) using antibodies to synthetic salmon GnRH (s-GnRH). Two centers containing immunoreactive cell bodies were observed in the forebrain, one located at the junction between the olfactory bulbs and the telencephalon and the other in the preoptic(More)
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