Influence of Pineal Gland on Spermatogenesis of Toad (Bufo melanostictus)
TL;DR: The relationship between the pineal gland and testes of the toad was investigated in breeding and hibernating seasons and it is speculated that the cyclic pineal activity might be responsible for the seasonal variation of spermatogenesis in the toads.
Abstract: The relationship between the pineal gland and testes of the toad was investigated in breeding and hibernating seasons. Pinealectomy increased spermatogenesis in hibernating toads but it failed to exert any effect during the breeding season. The pineals were found to be active during hibernation and atrophied in the breeding season. It is speculated that the cyclic pineal activity might be responsible for the seasonal variation of spermatogenesis in the toad.
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TL;DR: The data available to date do not support the concept that melatonin plays an important physiological role in the photoperiodic control of reproduction in non-mammalians.
116 citations
19 Apr 2016
37 citations
TL;DR: The hypothesis that melatonin may function as a serotonin receptor antagonist is proposed, supporting a direct effect of melatonin and corticosterone on courtship behavior that is independent of any effect on androgen concentrations.
36 citations
Cites background from "Influence of Pineal Gland on Sperma..."
...Pinealectomy of toads during the hibernation phase stimulated testicular maturation, while pinealectomy during the breeding season did not influence testicular function (Chanda and Biswas, 1984)....
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01 Jan 2011
TL;DR: Like most vertebrates, reproductive function in anuran amphibians depends on interactions between the hypothalamus, adenohypophysis, and gonads that are mediated by neural pathways operating across a classic endocrine circuitry.
Abstract: Publisher Summary The anuran fauna is extremely complex in terms of biogeography, ecology, and life history patterns. Anuran amphibians display a variety of reproductive modes including a nonplacental viviparous species. They also have a wide diversity of reproductive modes, but external aquatic fertilization without parental care is the ancestral and most widespread strategy. The known temperate anurans are all oviparous and all breed in water, lay their eggs, and have free-living larvae. Although most of these species have usually monogamic mating, polyandrous mating, in which several males attempt to mate simultaneously with a female, is rare in temperate species, but is not uncommon in tropical and subtropical species. The most important regulator of anuran reproduction is environmental temperature. Like most vertebrates, reproductive function in anuran amphibians depends on interactions between the hypothalamus, adenohypophysis, and gonads that are mediated by neural pathways operating across a classic endocrine circuitry.
24 citations
TL;DR: The sections in this article are: Circadian Pacemaking Systems in Invertebrates, Models and Mechanisms, Photoperiodic Time Measurement, Pineal and Melatonin, and Physiological Mechanisms.
Abstract: The sections in this article are:
1
Daily Rhythms
1.1
Models and Mechanisms
2
Circadian Pacemaking Systems in Invertebrates
2.1
Pacemakers in the Arthropod Brain
2.2
Circadian Pacemakers Outside the Nervous System in Insects
2.3
Pacemakers in the Gastropod Retina
2.4
Multioscillator Organization
2.5
Identification of Output Pathways
3
Circadian Pacemaking Systems in Vertebrates
3.1
The Mammalian SCN
3.2
Other Circadian Oscillators in Mammals
3.3
Hypothalamic Regulation of Circadian Function in Nonmammalian Vertebrates
3.4
The Pineal Organ
3.5
Eyes as Clocks
4
Photoreceptor Localization and Mechanisms of Entrainment in Invertebrates
4.1
Photoreceptive Input: Invertebrates
4.2
Mechanisms of Regulation of Pacemaker Phase
5
Photoreceptor Localization and Mechanisms of Entrainment in Vertebrates
5.1
Identification of Photoreceptors
5.2
Mechanisms of Regulation of Pacemaker Phase
6
Seasonality in Invertebrates
6.1
Modes of Seasonality
6.2
Timing of Seasonal Cycles
6.3
Photoperiodic Time Measurement
6.4
Mechanisms of Photoperiodic Time Measurement
6.5
The Photoperiodic Timer
6.6
The Photoperiodic Counter
6.7
Anatomical Location of Timers and Counters
6.8
Photoreceptors
6.9
Circannual Rhythms
7
Seasonality in Vertebrates
7.1
Photoperiodic Time Measurement: Models and Experimental Validation
8
Physiological Mechanisms
8.1
The Pineal and Melatonin: Mammals
8.2
Mechanisms of Pineal Action
8.3
The Pineal and Melatonin: Nonmammalian Vertebrates
8.4
Photoreceptive Inputs: Mammalian
8.5
Photoreceptive Inputs: Nonmammalian
8.6
Maternal–Fetal Transfer of Photoperiodic Information
9
Circannual Rhythms
9.1
Physiological Mechanisms
10
Concluding Comments
16 citations