Deakin University
Browse

File(s) not publicly available

Autocrine inhibition of milk secretion in the lactating tammar wallaby (Macropus eugenii)

journal contribution
posted on 1998-01-01, 00:00 authored by K A K Hendry, K J Simpson, Kevin Nicholas, C J Wilde
The lactating tammar wallaby progressively alters the rate of secretion and composition of its milk to provide appropriate nutrition for the developing offspring, whose needs are signalled by changes in the pattern and efficiency of its sucking. Tammars are also capable of asynchronous concurrent lactation, when the mother provides a dilute milk for a newborn young permanently attached to the teat (phase 2A of lactation), and a concentrated milk from an adjacent mammary gland for a young-at-heel (phase 3). The relationship between suckling behaviour and milk secretion, and the ability of adjacent glands to function independently, suggests that milk secretion is controlled locally, within each mammary gland, by a mechanism sensitive to frequency and completeness of milk removal. To determine if tammar milk contains a factor able to control milk secretion, milk fractions have been 6-30 kDa fraction of phase 3 whey was found to inhibit milk constituent synthesis and secretion in vitro, and inhibitory activity was associated with two discrete fractions obtained by anion exchange chromatography, which contained protein bands migrating anomalously at 66 kDa and 63 kDa in SDS-PAGE. These bands were recognised in Western blotting by antiserum raised against a bovine autocrine inhibitor of milk secretion. By the same criteria, milk secreted in phase 2B of tammar lactation, when milk secretion is low and suckling intermittent but less vigorous than phase 3, also contained a feedback inhibitor of milk secretion. The results indicate that, as in dairy animals, marsupial milk secretion is under local control through feedback inhibition by a milk protein, and raise the possibility that autocrine feedback may influence the transition from phase of low milk secretion (phase 2A, 2B) to a high rate in the final third phase of lactation.

History

Journal

Journal of Molecular Endocrinology

Volume

21

Issue

2

Pagination

169 - 177

ISSN

0952-5041

Usage metrics

    Research Publications

    Categories

    No categories selected

    Keywords

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC