Androgen-induced changes in Leydig cell ultrastructure and steroidogenesis in juvenile African catfish, Clarias gariepinus

被引:23
作者
Cavaco, JEB
van Blijswijk, B
Leatherland, JF
Goos, HJT
Schulz, RW
机构
[1] Univ Utrecht, Res Grp Comparat Endocrinol, Fac Biol, NL-3584 CH Utrecht, Netherlands
[2] Univ Guelph, Dept Biomed Sci, Ontario Vet Coll, Guelph, ON N1G 2W1, Canada
[3] Univ Algarve, UCTRA, Ctr Ciencias Mar, P-8000 Faro, Portugal
基金
加拿大自然科学与工程研究理事会;
关键词
teleost fish; puberty; testes; sex steroids; ultrastructure; steroidogenesis; Clarias gariepinus (Teleostei);
D O I
10.1007/s004410051357
中图分类号
Q2 [细胞生物学];
学科分类号
071009 ; 090102 ;
摘要
The present report focuses on the mechanism(s) involved in the steroid-induced decrease of androgen production in immature African catfish testes that was observed in previous studies. Juvenile animals were implanted with Silastic pellets containing different 11-oxygenated androgens (11-ketotestosterone, KT; 11 beta-hydroxyandrostenedione, OHA; 11-ketoandrostenedione, KA), testosterone (T) or estradiol-17 beta (E2). Control groups received steroid-free pellets. Two weeks later, testis tissue fragments were either incubated with increasing concentrations of catfish luteinizing hormone (LH), or incubated with [H-3]-pregnenolone ([H-3]-P5) or [H-3]-androstenedione ([H-3]-A). Tissue fragments were also prepared for the quantitative assessment of Leydig cell morphology. Most of the parameters studied were not affected significantly by implantation of E2, Implantation of all androgens inhibited both the basal and the LH-stimulated androgen secretory capacity in vitro. This was associated with a reduced size of the Leydig cells and loss of half of their mitochondria. The studies on the metabolism of tritiated steroid hormones indicated that steroidogenic steps prior to 11 beta-hydroxylation, probably C17-20 lyase activity, were affected by all androgens. Although the effects of Il-oxygenated androgens and T on Leydig cells were mostly similar, previous work showed that only the Ii-oxygenated androgens stimulated spermatogenesis, suggesting that distinct mechanisms of action are used by Ii-oxygenated androgens and T. These mechanisms, however, seem to merge on the same target(s) to impair Leydig cell androgen production. Such a negative feedback mechanism may be of relevance in the context of the decline in androgen secretion per milligram testis tissue that accompanies the first wave of spermatogenesis in pubertal African catfish.
引用
收藏
页码:291 / 299
页数:9
相关论文
共 44 条
  • [41] TRUDEAU VL, 1995, P 5 INT S REPR PHYS, P44
  • [42] GAS-CHROMATOGRAPHIC MASS-SPECTROMETRIC (GC-MS) ANALYSIS OF GONADAL-STEROIDS IN PLASMA OF THE MALE AFRICAN CATFISH, CLARIAS-GARIEPINUS - EFFECTS OF CASTRATION OR TREATMENT WITH GONADOTROPIN-RELEASING-HORMONE ANALOG
    VERMEULEN, GJ
    LAMBERT, JGD
    VANDERLOOY, MJW
    GOOS, HJT
    [J]. GENERAL AND COMPARATIVE ENDOCRINOLOGY, 1994, 96 (02) : 288 - 297
  • [43] STEROID-HORMONE SECRETION BY TESTICULAR TISSUE FROM AFRICAN CATFISH, CLARIAS-GARIEPINUS, IN PRIMARY CULTURE - IDENTIFICATION AND QUANTIFICATION BY GAS-CHROMATOGRAPHY - MASS-SPECTROMETRY
    VERMEULEN, GJ
    LAMBERT, JGD
    LENCZOWSKI, MJP
    GOOS, HJT
    [J]. FISH PHYSIOLOGY AND BIOCHEMISTRY, 1993, 12 (01) : 21 - 30
  • [44] A 2-RECEPTOR MODEL FOR SALMON GONADOTROPINS (GTH-I AND GTH-II)
    YAN, LG
    SWANSON, P
    DICKHOFF, WW
    [J]. BIOLOGY OF REPRODUCTION, 1992, 47 (03) : 418 - 427