Hormonal Regulation of Testicular Functions in Reptiles

Kumar, Sunil; Roy, Brototi; Rai, Umesh

doi:10.1016/b978-0-12-374930-7.10003-2

Cited by 13 publications

(15 citation statements)

References 125 publications

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“…28 The warmest temperatures during March (17.0 C), April (17.9 C), May (18.3 C), and June (17.2 C) at the study site 29 correspond with maximum testicular activity for this population of S. aeneus (March-May), and the highest concentration of spermatozoa in the lumina of the epididymis. These findings are consistent with previous studies in which warmest temperatures appear to favor the maximum spermatogenic activity.…”

Section: Discussionmentioning

confidence: 78%

“…A number of studies have shown that temperature is an important environmental cue in male reproductive cycles, 20,26,27,28 although other factors such as rainfall and day length have also been indicated elsewhere. 28 The warmest temperatures during March (17.0 C), April (17.9 C), May (18.3 C), and June (17.2 C) at the study site 29 correspond with maximum testicular activity for this population of S. aeneus (March-May), and the highest concentration of spermatozoa in the lumina of the epididymis.…”

Section: Discussionmentioning

confidence: 99%

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Seasonal spermatogenesis in the Mexican endemic oviparous lizard,Sceloporus aeneus(Squamata: Phrynosomatidae)

et al. 2014

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Oviparous species of exhibit either seasonal or continuous spermatogenesis and populations from high-elevation show a seasonal pattern known as spring reproductive activity. We studied the spermatogenic cycle of a high-elevation (2700 m) population of endemic oviparous lizard,, that resided south of México, D.F. Histological analyses were performed on the testes and reproductive ducts from individual lizards collected monthly. This population of showed a seasonal pattern of spermatogenesis, with 4 successive phases common in other lizards. These include: 1) Quiescence in August, which contained solely spermatogonia and Sertoli cells; 2) Testicular recrudescence (September-January) when testes became active with mitotic spermatogonia, spermatocytes beginning meiosis, and the early stages of spermiogenesis with spermatids; 3) Maximum testicular activity occurred from March to May and is when the largest spermiation events ensued within the germinal epithelia, which were also dominated by spermatids and spermiogenic cells; 4) Testicular regression in June was marked with the number of all germs cells decreasing rapidly and spermatogonia dominated the seminiferous epithelium. February was a transitional month between recrudescence and maximum activity. The highest sperm abundance in the lumina of epididymides was during maximum testicular activity (March-May). Thus, before and after these months fewer spermatozoa were detected within the excurrent ducts as the testis transitions from recrudescence to maximum activity in February and from maximum activity to quiescence in June. Maximum spermatogenic activity corresponds with warmest temperatures at this study site. This pattern known as spring reproductive activity with a fall recrudescence was similar to other oviparous species of genus

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Section: Discussionmentioning

confidence: 78%

Section: Discussionmentioning

confidence: 99%

Seasonal spermatogenesis in the Mexican endemic oviparous lizard,Sceloporus aeneus(Squamata: Phrynosomatidae)

et al. 2014

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“…Hypertrophy in the Leydig cells nuclear diameter is associated with its endocrine activity peak of testosterone synthesis, coinciding with the spermatogenesis (Volsøe 1944). This phenomenon suggests the involvement of Leydig cells in the sperm transport, aiding the contraction of seminiferous tubules (Kumar et al 2011). This phenomenon suggests the involvement of Leydig cells in the sperm transport, aiding the contraction of seminiferous tubules (Kumar et al 2011).…”

Section: Discussionmentioning

confidence: 85%

Reproductive biology of Philodryas patagoniensis (Snakes: Dipsadidae) in south Brazil: male reproductive cycle

et al. 2016

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“…Se reconocieron dos categorías de edad, jóvenes y adultos. En S. bicanthalis fueron considerados adultos los machos con una LHC > 35 mm (Hernández-Gallegos et al 2002), en el caso de las otras dos especies no existen trabajos previos que nos indicaran la talla mí-nima del adulto, por lo que, algunos individuos fueron disectados para establecer la edad adulta con base en la presencia de huevos (en oviducto) o folículos vitelogé-nicos (en ovario) en las hembras, y con el epidídimo con producción de espermatozoides en los machos (Kumar et al 2011).…”

Section: Métodounclassified

Frecuencia de pérdida de la cola en un ensamble de lagartijas de Oaxaca, México

García-Rosales

Martínez–Coronel

2016

AZM

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El presente estudio evaluó la influencia de la edad, el sexo y el hábitat sobre la frecuencia de pérdida de la cola en tres especies de lagartijas endémicas a México. Los taxa tratados son Sceloporus bicanthalis, S. subpictus y Mesaspis gadovii, las cuales son simpátricas en las montañas de los Valles Centrales de Oaxaca. Las diferencias en la frecuencia de pérdida de la cola fueron evaluadas por sexo, edad, hábitat y especie mediante una prueba de Chi cuadrada en un tamaño de muestra de 259 organismos recolectados entre abril de 2010 y marzo de 2011. Los resultados indican que la estructura del hábitat, el sexo o la edad de los individuos (excepto en M. gadovii) no influyeron de manera significativa en la frecuencia de mutilación de la cola en las tres especies analizadas. Sin embargo, se presentaron diferencias significativas entre especies, estas diferencias pueden ser consecuencia del comportamiento agonístico propio de cada especie, y de una presión de depredación diferente para cada taxon.

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Hormonal Regulation of Testicular Functions in Reptiles

Cited by 13 publications

References 125 publications

Seasonal spermatogenesis in the Mexican endemic oviparous lizard,Sceloporus aeneus(Squamata: Phrynosomatidae)

Seasonal spermatogenesis in the Mexican endemic oviparous lizard,Sceloporus aeneus(Squamata: Phrynosomatidae)

Reproductive biology of Philodryas patagoniensis (Snakes: Dipsadidae) in south Brazil: male reproductive cycle

Frecuencia de pérdida de la cola en un ensamble de lagartijas de Oaxaca, México

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