Testicular development and maturation of the hypothalamic-pituitary-testicular axis in the male tammar, Macropus eugenii

Williamson, Patrick; Fletcher, Timothy David; Renfree, M. B.

doi:10.1530/jrf.0.0880549

Cited by 30 publications

(34 citation statements)

References 9 publications

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“…All tissues were collected under RNase-free conditions. Developing testes from three fetuses sampled 1-2 days before birth (d25) and from pouch young aged d2 (nZ3), d8 (nZ3), d12 (nZ2), d21 (nZ3), d44 (nZ3), d80 (nZ2), d150 (nZ1), d264 (nZ1), d365 (nZ1), juveniles (w14 months old (nZ3)) (puberty/spermatogenesis in male tammar begins at around 19 months and males becomes fully mature at 25 months; Williamson et al 1990) and mature adults (nZ2) for molecular analysis were snap frozen in liquid nitrogen and stored at K80 8C until use. Mature sperm were collected from adult epididymides, in 1 X PBS and snap-frozen.…”

Section: Tissuesmentioning

confidence: 99%

A-kinase anchoring protein 4 has a conserved role in mammalian spermatogenesis

Pask

et al. 2009

Reproduction

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A-kinase anchor protein 4 (AKAP4) is an X-linked member of the AKAP family of scaffold proteins that anchor cAMP-dependent protein kinases and play an essential role in fibrous sheath assembly during spermatogenesis and flagellar function in spermatozoa. Marsupial spermatozoa differ in structural organization from those of eutherian mammals but data on the molecular control of their structure and function are limited. We therefore cloned and characterized the AKAP4 gene in a marsupial, the tammar wallaby (Macropus eugenii). The gene structure, sequence, and predicted protein of AKAP4 were highly conserved with that of eutherian orthologues and it mapped to the marsupial X-chromosome. There was no AKAP4 expression detected in the developing young. In the adult, AKAP4 expression was limited to the testis with a major transcript of 2.9 kb. AKAP4 mRNA was expressed in the cytoplasm of round and elongated spermatids while its protein was found on the principal piece of the flagellum in the sperm tail. This is consistent with its expression in other mammals. Thus, AKAP4 appears to have a conserved role in spermatogenesis for at least the last 166 million years of mammalian evolution. Reproduction (2009) 137 645-653

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Section: Tissuesmentioning

confidence: 99%

A-kinase anchoring protein 4 has a conserved role in mammalian spermatogenesis

Pask

et al. 2009

Reproduction

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“…The sparse amounts of lipids suggest a steroidogenesis functionality or an active androgen pathway. In marsupials, androgens have low levels until puberty, coinciding with the high levels of lipids in this phase (Williamson et al 1990, Renfree et al 1992.…”

Section: Discussionmentioning

confidence: 99%

Ultrastructure of spermatogenesis in Spix's yellow-toothed cavy (Galea spixii)

et al. 2014

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This was a pioneer study of the spermatogenic process from the onset of puberty in Spix's yellow-toothed cavies (SYC, Galea spixii) bred in captivity. The study aimed to characterize fine structure of spermatogenesis. Twelve testes from pubertal and post-pubertal SYC males were studied using transmission electron microscopy. Spermatogenesis can be divided into three phases: proliferation, meiosis, and spermiogenesis. In proliferation phase, three types of spermatogonia were identified and characterized as A dark , A pale , and B. In the second phase, spermatocytes (2n) undergo meiotic divisions that generate spermatids (n); the process begins in spermatocytes in the preleptotene stage when they increase their nuclear size, differentiating into spermatocytes in the leptotene stage when cell division is initiated. In addition, we found chromatin condensation, and formation of a structure composed of proteins that formed a central shaft and two lateral bars associated with pairing of homologous chromosomes. During spermiogenesis, the following main events occurred: condensation of nuclear chromatin, formation of acrosome with perfuratorium, elimination of residual cytoplasm, and development of the flagellum. The sperm head is different from that of other rodents. The endoplasmic reticulum and the Golgi complex are the two main organelles demonstrated during this process. These organelles collaborate through synthesis of proteins and hormones for the development of germ cells during spermatogenesis in SYC.

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“…Plasma testosterone concentrations were measured by a radioimmunoassay validated for the tammar (Williamson et al 1990). The antiserum (no.…”

Section: Testosterone Radioimmunoassaymentioning

confidence: 99%

Mating sequence, dominance and paternity success in captive male tammar wallabies

Hynes¹,

Rudd²,

Temple-Smith³

et al. 2005

Reproduction

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The tammar wallaby (Macropus eugenii) is a small, promiscuous, macropodid marsupial. Females usually produce a single young each year and there is a clear dominance hierarchy between adult males. The dominant male usually mates first and then guards the female to prevent access to her by other males. In this study, agonistic encounters and mating behaviour were observed to determine male dominance hierarchies in six groups of captive tammars consisting of a total of 23 males and 50 females. Mating behaviour was observed immediately post-partum when females were in oestrus and was correlated with plasma testosterone concentrations. Male mating sequences were recorded, and the paternity of offspring was determined by using seven macropodid marsupial microsatellites. Rates of sexual checking and aggression by males housed with females in oestrus in the non-breeding season were lower than in the breeding season. These males also had lower concentrations of testosterone, but were still able to sire young. High testosterone concentrations neither ensured dominance nor appeared to control directly the level of sexual activity. Females usually mated with more than one male. The dominant male most often secured the initial copulation (60%), but the first-mating male did not always secure parentage, with second and third matings resulting in as many young as first matings. Using these data, we were unable to discount first sire, last sire or equal chance models of paternity in this species. Half the young (50%) were sired by the dominant a male, but of the remaining progeny, the b male sired more (35%) than g and d males (15%). Dominance therefore is only a moderately effective predictor of paternity in the tammar. Although the dominant males gained most first matings and individually sired half of the offspring, the subdominant males still contributed significantly to the population, at least in captivity. Reproduction (2005) 130 123-130

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Testicular development and maturation of the hypothalamic-pituitary-testicular axis in the male tammar, Macropus eugenii

Cited by 30 publications

References 9 publications

A-kinase anchoring protein 4 has a conserved role in mammalian spermatogenesis

A-kinase anchoring protein 4 has a conserved role in mammalian spermatogenesis

Ultrastructure of spermatogenesis in Spix's yellow-toothed cavy (Galea spixii)

Mating sequence, dominance and paternity success in captive male tammar wallabies

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