386 research outputs found
IDENTIFICATION AND BIOSYNTHESIS OF NEUTRAL LIPIDS IN THE LIVER, TESTIS AND FAT BODY OF Rana esculenta
No full textTHE DIFFERENT METHABOLIC WAYS OF SOME PRECURSORS OF LIPIDS IN THE MOST IMPORTANT ORGANS OF REPRODUCTION ARE PRESENTE
Distribution of somatostatin-like immunoreactivity in the brain of the frog, Rana esculenta, during development
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PRELIMINARY STUDIES ON THE BIOSYNTHETIC ACTIVITY OF THE FAT BODY OF THE GREEN FROG (Rana esculenta)
No full textNeuropeptide Y: localization in the brain and pituitary of developing frog (Rana esculenta)
No full textInfluence of gonadectomy and steroid hormone replacement therapy on the gonadotropin-releasing hormone neuronal system in the anterior preoptic area of the frog (Rana esculenta) brain
No full text
Immunohistochemical demonstration of the presence and localization of diverse molecular forms of gonadotropin-releasing hormone in the lizard (Podarcis s. sicula) brain.
No full textThe presence and activity of brain, pituitary and testicular beta-endorphin (beta-EP)-like material have been studied in the frog, Rana esculenta, using reverse-phase high-pressure liquid chromatography, coupled with radioimmunoassay and immunocytochemistry. In-vivo and in-vitro treatments with naltrexone were carried out to assess the putative physiological activity of opioid peptides. beta-EP(1-31) and (1-27), together with their acetylated forms, have been identified in brain, pituitary and testis. In particular, beta-EP(1-31) concentrations peaked during July in the brain and pituitary, whilst in testes maximum concentrations were found in April and November. beta-EP immunoreactivity was present in the brain within the nucleus preopticus and nucleus infundibularis ventralis while positive fibres in the retrochiasmatic regions projected to the median eminence. In the testis, interstitial cells, canaliculi of the efferent system, spermatogonia and spermatocytes showed positive immunostaining for beta-EP. In intact animals, naltrexone treatment increased plasma and testicular androgen levels and this effect was confirmed in in-vitro incubations of minced testes. Naltrexone also induced a significant increase in germ cell degeneration. Our results indicated that an opioid system modulates the hypothalamus-pituitary-gonadal axis in the frog, Rana esculenta and, for the first time, we have shown that the testicular activity of a non-mammalian species may be regulated by opiates locall
Immunohistochemical demonstration of the presence and localization of diverse molecular forms of gonadotropin-releasing hormone in the lizard (Podarcis s. sicula) brain.
No full textThe presence and activity of brain, pituitary and testicular beta-endorphin (beta-EP)-like material have been studied in the frog, Rana esculenta, using reverse-phase high-pressure liquid chromatography, coupled with radioimmunoassay and immunocytochemistry. In-vivo and in-vitro treatments with naltrexone were carried out to assess the putative physiological activity of opioid peptides. beta-EP(1-31) and (1-27), together with their acetylated forms, have been identified in brain, pituitary and testis. In particular, beta-EP(1-31) concentrations peaked during July in the brain and pituitary, whilst in testes maximum concentrations were found in April and November. beta-EP immunoreactivity was present in the brain within the nucleus preopticus and nucleus infundibularis ventralis while positive fibres in the retrochiasmatic regions projected to the median eminence. In the testis, interstitial cells, canaliculi of the efferent system, spermatogonia and spermatocytes showed positive immunostaining for beta-EP. In intact animals, naltrexone treatment increased plasma and testicular androgen levels and this effect was confirmed in in-vitro incubations of minced testes. Naltrexone also induced a significant increase in germ cell degeneration. Our results indicated that an opioid system modulates the hypothalamus-pituitary-gonadal axis in the frog, Rana esculenta and, for the first time, we have shown that the testicular activity of a non-mammalian species may be regulated by opiates locall
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