PubMed Health⌕ Search

Biomedical subjects

Y Courty

Publications and source records attributed to Y Courty.

27 records · Page 2Linked to original sources
PubMed1986

Evolution and testosterone content of the epididymis during the annual cycle of the lizard Lacerta vivipara.

The lizard epididymis provides a model for studying the control, by testosterone, of a secretory activity related to the physiology of spermatozoa. To evaluate seasonal changes and to establish chronological correlations between the structure of the epididymis and its testosterone content, lizards (Lacerta vivipara) were killed between March (emergence) and October (retreat). The epididymal tissue was examined histologically and assayed for testosterone content. Ten stages of development were defined, mainly on the basis of the epithelial structure and the morphological features of secretory activity. Degeneration of the epithelium after the breeding period and its subsequent renewal also were considered. Increased epithelial height and secretory activity coincided with a progressive rise of the testosterone level, and a severe atrophy followed a sudden reduction of blood testosterone. Reorganization of the epithelium takes place when testosterone is at its lowest level, and the hormonal dependency of this stage is questionable. This study confirms in vivo, during a sexual cycle, experimental evidence previously obtained concerning testosterone's control of the secretory activity of the lizard epididymis.

Animals↗
PubMed1986

Effects of castration on the epididymis of a non-mammalian vertebrate: evolution of morphology, protein synthesis, and of specific mRNA levels.

The lizard epididymis is an androgen-dependent organ undergoing large variations in its structure and in protein synthesis ability during its annual cycle. It produces a major androgen-dependent protein, the L protein. This work reports the effects of castration performed at 3 prominent points of the sexual cycle: stage 1 (epithelium reorganization) stage 3 (onset of secretory activity) stage 6 (full secretory activity). Evolution of various parameters (organ weight, histology, amount of soluble proteins, rate of soluble protein synthesis and of specific protein synthesis: L protein, and mRNA levels) was considered over a period ranging from 7 days to 15, 30 and 60 days. Deprivation of the testis was followed by an organ involution which was more or less accentuated or more or less rapid according to the stage of the operation but some peculiarities need to be emphasized. At first, the evolution of the organ was not stopped but it proceeded: at stage 1, there was cell division and a correlated increase in total protein synthesis (without L protein synthesis), at stage 3 total protein synthesis and L protein mRNA levels increased (synthesis of L protein proceeded up to 30 to 60 days), at stage 6 the involution was accelerated. These effects concerning stage 1 and particularly stage 3 appeared as a kind of a paradoxical induction. Secondly, the epithelium underwent phases of destruction and regeneration which were obviously not controlled by the testis.

Animals↗
PubMed1986

[In vitro translation of RNA from lizard epididymis and identification of poly A RNA coding for a major androgen-dependent protein].

During the reproductive period (spring) the lizard epididymis secretes a soluble protein of an apparent molecular weight (MW) of 19,000, the protein L. This androgen dependent protein disappears during post-nuptial atrophy of the epididymis (summer). At two time intervals (spring and summer) total RNA were extracted and poly (A) RNA were prepared. The RNA were translated in a cell-free system (rabbit reticulocyte lysate) in the presence of 35S methionine. Labelled translation products were analyzed by polyacrylamide gel electrophoresis under denaturing conditions. Electrophoresis were preceded or not by immunoprecipitation with an antiserum raised against protein L. RNA extracted during spring coded for several unique bands including five immunoprecipitated proteins with close-related MW (21,000 to 25,000). When RNA were translated in the presence of dog microsomes, the five previously detected protein bands disappear although a 19,000 MW immunoprecipitated protein was clearly demonstrated. These proteins were not detected when RNA extracted in summer were used. The protein L appears to be synthesized as preprotein(s). Its (unique or several?) messenger is of poly A type; it is present in spring and absent or undetectable in these experimental conditions in summer.

Androgens↗
PubMed1980

[Simultaneous radioimmunoassay of androstenedione, testosterone and dihydrotestosterone. Application to the study of Leydig cell function].

A radioimmunological method for simultaneous dosage of androstenedione, testosterone and dihyhydrotestosterone is described. This technique was applied to the study of the secretions of Leydig cells removed from hypophysectomized boar testis, in organ cultures. The releasing kinetic of the 3 steroids under hCG influence was studied; after 12 days of culture, the medium was analysed during 96 hours (8 periods of 12 hours); the steroid production started immediately and showed a progressive increase then slightly slowed down at the end of the 4 days.

Androstenedione↗
PubMed1980

[Testicular androgens and spermatogenetic cycles in the viviparous lizard].

Androstenedione, testosterone and dihydrotestosterone levels were measured in the testis of 36 males of the viviparous lizard throughout a period (from end of May to end of July) characterized by the transition between two spermatogenetic cycles and by very low levels of plasma testosterone. The sudden rise of testicular testosterone and androstenedione in June is concomitant with a degeneration of the seminiferous epithelium. It coincides with a transient appearance of testicular dihydrotestosterone. During the next decline in the levels of testosterone and androstenedione, it occurs a restoration of the seminiferous tubules which resume spermatogenesis (proliferation of spermatogenia and prophase of first meiotic division). The part played by some testicular steroids in the control of spermatogenesis is discussed.

Androstenedione↗
PubMedDate not supplied

Involvement of the C-terminal end of the prostrate-specific antigen in a conformational epitope: characterization by proteolytic degradation of monoclonal antibody-bound antigen and mass spectrometry.

Prostate-specific antigen (PSA), a 237-amino acid glycoprotein, encoded by the hKLK3 gene, is widely used as a serum marker for the diagnosis and management of prostate cancer. We report here the localization of a conformational epitope recognized by the anti-total PSA monoclonal antibody (mAb) 11E5C6, by proteolytic degradation of mAb-bound antigen followed by mass spectrometric analyses of the peptides generated. These two technologies, combined with molecular display, allowed the identification of amino acid residues contained within three different peptides distant on the PSA sequence, but close in the PSA three-dimensional structure, that may be part of the mAb 11E5C6 epitope. The last four C-terminal amino acid residues are included in this epitope, as well as certain other C-terminal residues between Y225 and T232. The involvement of the PSA C-terminal end in the mAb 11E5C6 epitope was confirmed by western blotting experiments with the recombinant protein proPSA-RP1, resulting from the cloning of an alternative transcript of the hKLK3 gene, in which the PSA C-terminal end was deleted and replaced by another sequence. Although the anti-total PSA mAb 5D5A5 used as a control bound proPSA-RP1, mAb 11E5C6 did not. The requirement of the C-terminal end for the recognition by mAb 11E5C6 may be useful for the discrimination of PSA-related forms.

Amino Acid Sequence↗