Effects of daily melatonin injections on the photoperiodic gonadal response of the female frog Rana ridibunda

Effects of Melatonin on Gonadal Steroids and Glucose Plasma Levels in Frogs (Rana perezi and Rana temporaria)

“…As far as we know, no report dealing with the effect of melatonin on steroid levels in amphibia females in vivo has appeared. Unfortunately, in other works, steroids were not measured [Delgado et al, 1983;Kupwade and Saidapur, 19861. In the experimental conditions of the present study melatonin treatment did not have any effect on testosterone or estradiol plasma levels. Previous studies on the seasonal fluctuations of plasma steroids in Ranaperezi females suggested that in summer and autumn the estradiol levels are very low while in late winter and spring, just before breeding season, the levels are higher [Delgado, 19871. It is likely that the effect of melatonin could be observed during the spring when estradiol levels are high and temperature and photoperiod are increasing.…”

Effects of Melatonin on Gonadal Steroids and Glucose Plasma Levels in Frogs (Rana perezi and Rana temporaria)

“…As far as we know, no report dealing with the effect of melatonin on steroid levels in amphibia females in vivo has appeared. Unfortunately, in other works, steroids were not measured [Delgado et al, 1983;Kupwade and Saidapur, 19861. In the experimental conditions of the present study melatonin treatment did not have any effect on testosterone or estradiol plasma levels. Previous studies on the seasonal fluctuations of plasma steroids in Ranaperezi females suggested that in summer and autumn the estradiol levels are very low while in late winter and spring, just before breeding season, the levels are higher [Delgado, 19871. It is likely that the effect of melatonin could be observed during the spring when estradiol levels are high and temperature and photoperiod are increasing.…”

Daily and Seasonal Rhythms

“…Observations on the effects of pinealectomy and melatonin are few in amphibians (16, 17, 175, 232, 348, 551, 774) and only somewhat more in fish (110, 234, 235, 298, 334, 335, 348, 507, 508, 509, 877, 878, 962, 1052). Antigonadal and progonadal effects of pinealectomy and melatonin either are or are not observed in a given species, depending on the specific temperature and lighting conditions and the phase of the annual cycle.…”

Melatonin Induced Changes in Specific Growth Rate, Gonadal Maturity, Lipid and Protein Production in Nile Tilapia Oreochromis niloticus (Linnaeus 1758)

“…Melatonin-treated Rana ridibunda maintained on a long photoperiod (18 L:6 D) produced significantly smaller gonads than control animals. Frogs injected daily with melatonin exhibited a substantial decrease in ovarian weight when compared to saline-injected animals ( Delgado et al, 1983 ).…”

Effects of Melatonin on Gonadal Steroids and Glucose Plasma Levels in Frogs (Rana perezi and Rana temporaria)

“…As far as we know, no report dealing with the effect of melatonin on steroid levels in amphibia females in vivo has appeared. Unfortunately, in other works, steroids were not measured [Delgado et al, 1983;Kupwade and Saidapur, 19861. In the experimental conditions of the present study melatonin treatment did not have any effect on testosterone or estradiol plasma levels. Previous studies on the seasonal fluctuations of plasma steroids in Ranaperezi females suggested that in summer and autumn the estradiol levels are very low while in late winter and spring, just before breeding season, the levels are higher [Delgado, 19871. It is likely that the effect of melatonin could be observed during the spring when estradiol levels are high and temperature and photoperiod are increasing.…”

Daily and Seasonal Rhythms

“…Observations on the effects of pinealectomy and melatonin are few in amphibians (16, 17, 175, 232, 348, 551, 774) and only somewhat more in fish (110, 234, 235, 298, 334, 335, 348, 507, 508, 509, 877, 878, 962, 1052). Antigonadal and progonadal effects of pinealectomy and melatonin either are or are not observed in a given species, depending on the specific temperature and lighting conditions and the phase of the annual cycle.…”

Melatonin Induced Changes in Specific Growth Rate, Gonadal Maturity, Lipid and Protein Production in Nile Tilapia Oreochromis niloticus (Linnaeus 1758)

“…Melatonin-treated Rana ridibunda maintained on a long photoperiod (18 L:6 D) produced significantly smaller gonads than control animals. Frogs injected daily with melatonin exhibited a substantial decrease in ovarian weight when compared to saline-injected animals ( Delgado et al, 1983 ).…”

Effects of Melatonin on Gonadal Steroids and Glucose Plasma Levels in Frogs (Rana perezi and Rana temporaria)

“…As far as we know, no report dealing with the effect of melatonin on steroid levels in amphibia females in vivo has appeared. Unfortunately, in other works, steroids were not measured [Delgado et al, 1983;Kupwade and Saidapur, 19861. In the experimental conditions of the present study melatonin treatment did not have any effect on testosterone or estradiol plasma levels. Previous studies on the seasonal fluctuations of plasma steroids in Ranaperezi females suggested that in summer and autumn the estradiol levels are very low while in late winter and spring, just before breeding season, the levels are higher [Delgado, 19871. It is likely that the effect of melatonin could be observed during the spring when estradiol levels are high and temperature and photoperiod are increasing.…”

Daily and Seasonal Rhythms

“…Observations on the effects of pinealectomy and melatonin are few in amphibians (16, 17, 175, 232, 348, 551, 774) and only somewhat more in fish (110, 234, 235, 298, 334, 335, 348, 507, 508, 509, 877, 878, 962, 1052). Antigonadal and progonadal effects of pinealectomy and melatonin either are or are not observed in a given species, depending on the specific temperature and lighting conditions and the phase of the annual cycle.…”

Melatonin Induced Changes in Specific Growth Rate, Gonadal Maturity, Lipid and Protein Production in Nile Tilapia Oreochromis niloticus (Linnaeus 1758)

“…Melatonin-treated Rana ridibunda maintained on a long photoperiod (18 L:6 D) produced significantly smaller gonads than control animals. Frogs injected daily with melatonin exhibited a substantial decrease in ovarian weight when compared to saline-injected animals ( Delgado et al, 1983 ).…”