The ultrastructure of the pituitary and the adrenal gland of three newborn marsupials (Dasyurus hallucatus, Trichosurus vulpecula and Isoodon macrourus)

Gemmell, R. T.; Nelson, Jacob L.

doi:10.1007/bf00304736

Cited by 9 publications

(3 citation statements)

References 24 publications

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“…Ultrastructural and immunohistochemical evidence show that the pituitary gland of the newborn marsupial is capable of synthesis and secretion of GH (Leatherland & Renfree 1983, Walker & Gemmell 1983, Gemmell & Nelson 1988. Further, with the radioimmunoassay used in the present study, GH could be detected in the head of newborn pouch young (11 ng/head), and by day 12 post-partum the pituitary gland content was 0·75 0·21 µg .…”

Section: Discussionsupporting

confidence: 54%

Plasma growth hormone and growth hormone-binding protein during development in the marsupial brushtail possum (Trichosurus vulpecula)

Saunders

Gemmell²,

Waters³

et al. 2002

Journal of Endocrinology

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Plasma concentrations of growth hormone (GH) were measured in the brushtail possum (Trichosurus vulpecula) pouch young from 25 through to 198 days post-partum (n=71). GH concentrations were highest early in pouch life (around 100 ng/ml), and thereafter declined in an exponential fashion to reach adult concentrations (10·8 1·8 ng/ml; n=21) by approximately 121-145 days post-partum, one to two months before the young is weaned. Growth hormone-binding protein (GHBP), which has been shown to modify the cellular actions of GH in eutherian mammals, was identified for the first time in a marsupial. Based on size exclusion gel filtration, possum GHBP had an estimated molecular mass of ]65 kDa, similar to that identified in other mammalian species, and binding of 125 I-labelled human GH (hGH) was displaced by excess hGH (20 µg). An immunoprecipitation method, in which plasma GHBP was rendered polyethylene glycol precipitable with a monoclonal antibody to the rabbit GHBP/GH receptor (MAb 43) and labelled with 125 I-hGH, was used to quantitate plasma GHBP by Scatchard analysis in the developing (pooled plasma samples) and adult (individual animals) possums. Binding affinity (K a ) values in pouch young aged between 45 and 54 and 144 and 153 days post-partum varied between 1·0 and 2·4 10 9 /M, which was slightly higher than that in adult plasma (0·96 0·2 10 9 /M, n=6). Binding capacity (B max ) values increased from nondetectable levels in animals aged 25-38 days post-partum to reach concentrations around half that seen in the adult (1·4 0·2 10 -9 M) by about 117 days post-partum and remained at this level until 153 days post-partum. Therefore, in early pouch life when plasma GH concentrations are highest, the very low concentrations of GHBP are unlikely to be important in terms of competing with GH-receptor for ligand or altering the half-life of circulating GH.

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Section: Discussionsupporting

confidence: 54%

Plasma growth hormone and growth hormone-binding protein during development in the marsupial brushtail possum (Trichosurus vulpecula)

Saunders

Gemmell²,

Waters³

et al. 2002

Journal of Endocrinology

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“…Secretory granules have been observed in the anterior pituitary, and morphological and biochemical evidence for the production of steroid hormones by the cortex of the newborn marsupial adrenal gland has been obtained from all species of marsupial examined (Gemmell and Rose, 1989;Sherman and Krause, 1990). The fetal pituitary and adrenal glands are functional at birth and are thus capable of initiating parturition (Walker and Gemmell, 1983;Gemmell and Nelson, 1988;Gemmell and Rose, 1989). The presence of hormones within the posterior pituitary of the newborn possum suggests that this part of the pituitary may also be involved with parturition.…”

Section: Discussionmentioning

confidence: 99%

“…Administration of adrenocorticotrophic hormone to the fetus induces 0 1993 WILEY-LISS, INC birth in various eutherians (Liggins et al, 1973), suggesting that the anterior region of the pituitary is required for birth. The anterior pituitary and the adrenal glands of various marsupials are capable of secreting hormones a t birth (Gemmell et al, 1982;Gemmell and Nelson, 1988;Gemmell and Rose, 1989), and the pituitary-adrenal axis may play an important role in controlling the length of gestation in both eutherians and marsupials.…”

mentioning

confidence: 99%

Posterior pituitary of the newborn marsupial possum, Trichosurus vulpecula

et al. 1993

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The fetal anterior pituitary-adrenal axis is thought to be involved in the initiation of birth in both eutherian and marsupial mammals. Little is known about the structure and function of the posterior pituitary at birth in the marsupial. Immunocytochemistry, high pressure liquid chromatography, and radioimmunoassay were used to identify vasopressin and mesotocin in the posterior pituitary of a newborn marsupial, the brushtail possum, Trichosurus vulpecula. The concentrations of vasopressin and mesotocin in the head of the newborn possum were 0.34 and 0.28 ng, respectively. The concentration of vasopressin was always greater than that of mesotocin, and the amounts of neuropeptides present in the head increased as the possum developed.

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Postnatal development of the skin of the marsupial native cat Dasyurus hallucatus

Pralomkarn

Nelson

Gemmell

1990

Journal of Morphology

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Skin development of the Northern native cat was examined from birth to weaning at 150 days post partum. An outer layer of cells, termed the periderm or epitrichium, is present on the epidermis of the newborn. This layer of cells is not discernible at 7 days post partum. Skin development of the native cat differs from that of the eutherian mammal. The periderm of the eutherian is no longer discernible when the developing hairs first penetrate the epidermis. In the marsupial, this loss of the periderm occurs well before the appearance of follicles. Melanocytes and Langerhans cells are seen at day 23 post partum, follicles at day 30, sebaceous glands at day 59, and sweat glands at day 67. Thus, when the mother first leaves her young in the nest at about days 60 to 70 of lactation, the skin is at a stage of development that will assist the young with thermoregulation. The skin continues to develop throughout lactation and attains an adult appearance by day 150 post partum.

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The ultrastructure of the pituitary and the adrenal gland of three newborn marsupials (Dasyurus hallucatus, Trichosurus vulpecula and Isoodon macrourus)

Cited by 9 publications

References 24 publications

Plasma growth hormone and growth hormone-binding protein during development in the marsupial brushtail possum (Trichosurus vulpecula)

Plasma growth hormone and growth hormone-binding protein during development in the marsupial brushtail possum (Trichosurus vulpecula)

Posterior pituitary of the newborn marsupial possum, Trichosurus vulpecula

Postnatal development of the skin of the marsupial native cat Dasyurus hallucatus

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