scholarly journals The c-kit receptor protein in the testis of green frog Rana esculenta: seasonal changes in relationship to testosterone titres and spermatogonial proliferation

Reproduction ◽  
2007 ◽  
Vol 133 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Franca Raucci ◽  
Maria Maddalena Di Fiore
Keyword(s):  
Germ Cell ◽  
Mitotic Activity ◽  
Rana Esculenta ◽  
Reproductive Period ◽  
Receptor Protein ◽  
Germinal Epithelium ◽  
Positive Staining ◽  
Green Frog ◽  
Cyclic Changes ◽  
Spermatogonial Proliferation

The green frogRana esculentais a seasonal breeder. The cyclic changes between almost arrested and highly activated spermatogenesis offer an ideal model to study basic mechanisms of spermatogenesis. In this study, we demonstrated, to our knowledge for the first time,c-kitreceptor positive cells in the testis of this amphibian. The presence ofc-kitreceptor protein was confirmed by western blotting (Wb) analyses carried out in the testis during all the three main phases of the sexual cycle. The antibody recognized a band of about 150 kDa that was correlated with the positive staining in the germinal epithelium. The immunolabelling forc-kitreceptor, evaluated by immunohistochemistry (IHC), was localized in I and II spermatogonia (SPG), in I and II spermatocytes, in both elongating spermatids and spermatozoa and in the Leydig cells. Furthermore,c-kitexpression showed a seasonal pattern connected with both testicular and plasma profiles of testosterone during the reproductive cycle. The highest expression ofc-kitreceptor occurred during the reproductive period, when the testis exhibited the maximum concentration of testosterone. In this period, the mitotic activity of germ cell, assessed by both Wb and IHC analyses for proliferating cell nuclear antigen (PCNA), was intensive. Indeed, during the post-reproductive period, testosterone titres were the lowest and the expression of both PCNA andc-kitreceptor protein in the testis, although present, is minor when compared with the reproductive phase. This evidence suggests that cell division can continue sufficiently to accumulate SPG for the next spring, when new germinal cells undergo multiplication. Finally, during the pre-reproductive period, testosterone levels begin to increase and mitotic activity of germinal epithelium is comparably enhanced. These events seem to precede the period of maximum stimulated spermatogonial proliferation, i.e. the reproductive period. These results suggest that thec-kitreceptor may play a role in germ cell proliferation and provide a basis for future detailed investigation of regulatory factors of the proliferation of SPG.

scholarly journals Inhibition of the basal and oestradiol-stimulated mitotic activity of primary spermatogonia by melatonin in the testis of the frog, Rana esculenta, in vivo and in vitro

Reproduction ◽  
2003 ◽  
pp. 83-90 ◽  
Author(s):  
M d'Istria ◽  
C Palmiero ◽  
I Serino ◽  
G Izzo ◽  
S Minucci
Keyword(s):  
Mitotic Activity ◽  
Leydig Cells ◽  
Rana Esculenta ◽  
Inhibitory Effect ◽  
Morphological Observation ◽  
Physiological Concentration ◽  
First Time ◽  
Spermatogonial Proliferation

Melatonin has a direct inhibitory effect on the basal and oestradiol-stimulated mitotic activity of primary spermatogonia in the testis of the frog, Rana esculenta. In this study oestradiol was used to induce spermatogonial proliferation to verify the anti-proliferative effect of melatonin. The colchicine metaphase arrest technique was used. The results obtained from in vivo experiments confirm that oestradiol increases the mitotic index of primary spermatogonia and, for the first time, indicate that melatonin has an inhibitory role on the proliferation of primary spermatogonia in the frog testis. Similar results were obtained from testes of melatonin-injected frogs that were exposed to oestradiol in vitro; in fact spermatogonia were unresponsive to hormonal stimulation. In addition, in short-term cultured testes, melatonin (at physiological concentration) interferes with the effects of oestradiol on spermatogonial proliferation, supporting the hypothesis that melatonin exerts the inhibitory effect directly via its local action on the frog gonads. Morphological observation after in vivo or in vitro melatonin treatments indicates that Leydig cells display degenerative features, whereas in adjacent germinal tubules, Sertoli cells show heterochromatic nuclei. These results indicate that melatonin may act on Leydig cells and confirm that there is a paracrine interaction between interstitial and germinal compartments. The results of the present study indicate, for the first time, that melatonin may be directly involved in the inhibitory control of spermatogonial proliferation in the testis of the frog, R. esculenta.

scholarly journals Testicular endocrine activity is upregulated by D-aspartic acid in the green frog, Rana esculenta

2004 ◽  
Vol 182 (2) ◽  
pp. 365-376 ◽  
Author(s):  
F Raucci ◽  
L Assisi ◽  
S D'Aniello ◽  
P Spinelli ◽  
V Botte ◽  
...  
Keyword(s):  
Amino Acid ◽  
Aspartic Acid ◽  
Reproductive Cycle ◽  
Rana Esculenta ◽  
Reproductive Period ◽  
Nuclear Antigen ◽  
Green Frog ◽  
Endocrine Activity ◽  
Testosterone Levels ◽  
Stimulation Of

This study investigated the involvement of D-aspartic acid (D-Asp) in testicular steroidogenesis of the green frog Rana esculenta and its effect on stimulation of thumb pad morphology and glandular activity, a typical testosterone-dependent secondary sexual characteristic in this amphibian species. In the testis, D-Asp concentrations vary significantly during the reproductive cycle: they are low in pre- and post-reproductive periods, but reach peak levels in the reproductive period (140-236 nmol/g wet tissue). Moreover, the concentrations of D-Asp in the testis through the sexual cycle positively match the testosterone levels in the gonad and the plasma. The racemase activity evaluated during the cycle expresses its peak when D-Asp and testosterone levels are highest, that is, during the reproductive period, confirming the synthesis of D-Asp from L-Asp by an aspartate racemase. Short-term in vivo experiments consisting of a single injection of D-Asp (2.0 micro mol/g body weight) demonstrated that this amino acid accumulates significantly in the testis, and after 3 h its uptake is coupled with a testosterone increase in both testis and plasma. Moreover, within 18 h of amino acid administration, the D-Asp concentration in the testis decreased along with the testosterone titer to prestimulation levels. Other amino acids (L-Asp, D-Glu and L-Glu) used instead of D-Asp were ineffective, confirming that the significant increase in testicular testosterone was a specific feature of this amino acid. In long-term experiments, D-Asp had been administered chronically to frogs caught during the three phases of the reproductive cycle, inducing testosterone increase and 17beta-estradiol decrease in the gonad during the pre- and post-reproductive period, and vice versa during the reproductive period. The stimulatory effect of D-Asp on testosterone production by the testis is consistent with the stimulation of spermatogenesis and the maturation of thumb pads occurring in D-Asp-treated frogs. In these last animals, there was an increase of seminiferous ampoule area and a higher number of spermatids and sperm. Moreover, in spermatogonia I and II and in spermatocytes, a proliferating cell nuclear antigen (PCNA) intense immunopositivity was observed. In addition, the thumb pads of D-Asp-treated frogs compared with controls showed a significantly thicker epithelial lining, a wider area of their glands with taller secretion cells, and more numerous, PAS-positive-rich secretions. Finally, these results provide functional evidence for a biologic role of D-Asp in amphibian male steroidogenesis; therefore, this unusual amino acid could be considered a modulatory agent for reproductive processes.

Plasma sex hormones and post-reproductive period in the green frog, Rana esculenta complex

1984 ◽  
Vol 54 (3) ◽  
pp. 372-377 ◽  
Author(s):  
A. Polzonetti-Magni ◽  
V. Botte ◽  
L. Bellini-Cardellini ◽  
A. Gobbetti ◽  
A. Crasto
Keyword(s):  
Sex Hormones ◽  
Rana Esculenta ◽  
Reproductive Period ◽  
Green Frog ◽  
Rana Esculenta Complex

CYCLIC CHANGES IN THE GONAD OF THE AMERICAN OYSTER, CRASSOSTREA VIRGINICA (GMELIN)

1964 ◽  
Vol 42 (2) ◽  
pp. 305-321 ◽  
Author(s):  
Austina V. Kennedy ◽  
Helen I. Battle
Keyword(s):  
Crassostrea Virginica ◽  
Gonadal Development ◽  
Germinal Epithelium ◽  
Nuclear Area ◽  
Seasonal Growth ◽  
Body Width ◽  
Visceral Mass ◽  
Current Season ◽  
Primary Oocyte ◽  
Cyclic Changes

Cyclic changes in the gonad of Crassostrea virginica (Gmelin), a dioecious, oviparous lamellibranch, are described as they occurred toward the most northerly limit of the range, Malpeque Bay, P.E.I., Canada, during 1961 and 1962. The gonad, composed of right and left gonadal lobes lying immediately beneath the mantle, consists of extensively branched follicles comprising the outer margin of the visceral mass. The follicles open into peripherally located ducts which lead into paired gonoducts terminating in the suprabranchial chamber. During the fall and winter the germinal epithelium is in an indifferent or inactive state. The sex for the current season is distinguishable when proliferation commences in May. Maximum gonadal development occurs in late June or early July as determined by comparison of gonadal width to body width in mid-transverse sections. Primary oocytes are initially distinguishable from oogonia by the presence of a distinct nucleolus, and later by an amphinucleolus consisting of a plasmosome and a karyosome. Seasonal growth of the primary oocyte was followed by a planimetry method using measurements of total area and nuclear area from prepared sections. The spindle for the first meiotic division is established immediately on rupture of the oocyte from the follicular wall. Spermatogenesis and spermiogenesis are completed within the follicle. Following spawning, amoebocytes infiltrate the follicles and interfollicular connective tissue to phagocytize unspawned gametes. By late October the follicles of both male and female consist of a low germinal epithelium and a few unresorbed gametes, and remain inactive until proliferation the following spring.

Mitotic activity of germ cells during normal development of Xenopus laevis tadpoles

Development ◽  
1975 ◽  
Vol 34 (3) ◽  
pp. 687-694
Author(s):  
Ken-Ichi Ijiri ◽  
Nobuo Egami
Keyword(s):  
Xenopus Laevis ◽  
Germ Cell ◽  
Mitotic Activity ◽  
Germ Cells ◽  
Regional Difference ◽  
Normal Development ◽  
Uniform Value ◽  
Interesting Conclusion ◽  
Spatio Temporal ◽  
Gland Development

Data on the spatio-temporal pattern of germ cell proliferation in Xenopus laevis tadpoles were obtained, tracing the germ cells from the cloacal position forward. This spatial pattern in germ cell distribution and its change during normal development clearly coincided with histological observations of germ gland development. By application of regression lines to the analysis of this complex pattern, an interesting conclusion about the mitotic activity of germ cells was suggested. While the mitotic activity of germ cells before sexual differentiation shows a regional difference along the germ-cell-containing ridge (GCCR), the doubling time of sexually differentiated gonia seems to show a uniform value over the whole GCCR

scholarly journals Reproductive cycle of the Neotropical cichlid yellow peacock bass Cichla kelberi: A novel pattern of testicular development

2013 ◽  
Vol 11 (3) ◽  
pp. 587-596 ◽  
Author(s):  
Diógenes Henrique de Siqueira-Silva ◽  
Carlos Alberto Vicentini ◽  
Alexandre Ninhaus-Silveira ◽  
Rosicleire Veríssimo-Silveira
Keyword(s):  
Reproductive Cycle ◽  
Germ Cells ◽  
Light Microscope ◽  
Morphological Changes ◽  
Germinal Epithelium ◽  
Testicular Development ◽  
Preparatory Phase ◽  
Testicular Morphology ◽  
Peacock Bass ◽  
Spermatogonial Proliferation

The present study describes the testicular maturation phases (associating the germ cells development and the morphological changes suffered by the germinal epithelium along the whole year), and the testicular morphology in the yellow peacock bass Cichla kelberi, relating it to other species. For this purpose, 78 specimens were studied according conventional techniques of light microscope. The testes in C. kelberi were classified as unrestricted spermatogonial lobular, an apomorphic characteristic in the recent groups of Teleost. Furthermore, were defined five testicular maturation phases: Preparatory phase; Early Germinal Epithelium Development; Mid Germinal Epithelium Development; Late Germinal Epithelium Development and; Regression. Similar classifications were described to other species indicating that the testicular classifications based on this propose, can be applied to lots of fishes. However, besides it similarity, the testicular reproductive cycle of C. kelberifollows a different pattern in the Regression phase, on which the gonadal restructuration and the spermatogonial proliferation gathers at the same time. So, the testes in C. kelberi never return to the Preparatory phase to start a new reproductive cycle, being this one present only at the first reproductive cycle in this species. This fact also explains the absence of individuals totally spent after their first reproductive cycle.

The implication of ribonucleic acids in oviduct growth in the green frog, Rana esculenta

1976 ◽  
Vol 28 (1) ◽  
pp. 96-99
Author(s):  
A. Polzonetti-Magni ◽  
L. Bellini-Cardellini ◽  
V. Boote
Keyword(s):  
Rana Esculenta ◽  
Green Frog ◽  
Ribonucleic Acids
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