1,720,987 research outputs found
The androgen receptor mRNA is up-regulated by testosterone in both the Harderian gland and thumb pad of the frog, Rana esculenta
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Effects of gonadectomy and temperature on the N-acetyltransferase activity in the harderian gland of the green frog Rana esculenta
No full textA comparative study of melatonin production in the retina, pineal gland and harderian gland of Bufo viridis and Rana esculenta
No full textEffect of castration and testosterone therapy on harderian gland protein patterns of the golden hamster (Mesocricetus auratus)
No full textInhibition of the increased 17ß-estradiol-induced mast cell number by melatonin in the testis of the frog Rana esculenta, in vivo and in vitro
No full textIn the present study, we have utilized 17beta-estradiol to
induce the increase of mast cell number in order to verify
the melatonin effect on mast cell accumulation in the frog
testicular interstitium. Data obtained from in vivo
experiments confirm that 17beta-estradiol increases the mast
cell number and indicate a melatonin-inhibitory role in
their accumulation in the frog testis. In addition,
melatonin interferes with the effects of estradiol on the
increase of mast cell number in short-term cultured testes,
and this result has also been obtained in a dose–response
experiment at physiological concentration. The data
suggest that melatonin acts on mast cell number directly
via its local action in the frog gonads. In conclusion, our
study shows, for the first time, that melatonin may
interfere, probably via estrogen receptors, with the
differentiation and/or proliferation of mast cells induced
by estradiol treatment either in vivo or in vitro in the testis
of the frog Rana esculenta
A new sex dimorphism in the Harderian gland of the frog Rana esculenta.
No full textThe Harderian gland (hg) is the only gland found in the orbits of the frog Rana esculenta, and it has the primary role of lubricaing the eyes. The secretory activity of the frog hg is seasonal, showing the highest value in summer. To date, there is little information on frog hg gene expression, previously we identified a novel mRNA named "harderin" whose deduced protein has no significant homology with other proteins. This transcript was detected only in the RNA of frog hg suggesting a tissue specific expression of the protein. The present study reports, for the first time, that harderin transcript is differentially expressed in the hg of both sexes of R.esculenta during the whole annual secretory cycle, suggesting a sexual dimorphism. RT-PCR analysis, performed throughout the annual secretory cycle, revealed that harderin transcript is expressed during the whole year in the hg of both sexes, showing a higher level of expression in the female glands at anytime. In particular, two peaks of expression, in February and in June, were observed in the female glands, while only the February peak was observed in those of males. In situ hybridization indicated thar harderin mRNA was expressed in the cytoplasm of the majority of acinar secretory cells and confirmed that female glands had significantly higher levels of expression than those of males. Experiments of castration and/or replacement therapy performed inn June, when estradiol peaks only in females, evidenced a significant decrease of harderin expression in the hg of females; this effect is counteracted by estradiol (testosterone dministration had no effect), suggesting that this new sexual dimorphism is under estradiol control
First evidence of a cDNA encoding for a melatonin receptor (mel 1b) in brain, retina, and testis of Pelophylax esculentus
No full textMelatonin, nocturnally secreted by the pineal gland, regulates a variety of physiological functions,
including reproduction. Here, we investigated the evidence of melatonin binding sites in frog tissue
(brain, retina, and testis) through saturation and competition binding experiments. In the frog,
Pelophylax esculentus, our results confirm the presence of a single class of melatonin-specific
binding sites in the brain and retina, but not in the testis. Further experiments have been done
using biomolecular approaches (PCR analysis). Here, we report the isolation of a cDNA encoding for
a melatonin receptor type (mel1b) from brain, retina, and testis of the P. esculentus. PCR analysis
revealed that melatonin expression is higher in the brain and retina, whereas it is lower in the
testis. The presence of a melatonin receptor transcript in the frog testis corroborates our previous
results obtained in in vitro experiments that suggest that melatonin might act directly in male
vertebrate gonads, and indicates that the frog testis may be a suitable model to verify the role of
indolamine in testicular activity
Seasonal variations in the daily rhythm of melatonin and NAT activity in the Harderian gland, retina, pineal gland, and serum of the green frog, Rana esculenta
No full textInhibition 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
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