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Biomedical subjects

M Wallis

Publications and source records attributed to M Wallis.

At least 109 records · Page 6Linked to original sources
PubMed1977

Iodinated bovine prolactin. Characterization and binding to mammary gland cells.

Iodinated bovine prolactin (2.6 iodine atoms/molecule; labelled with a trace of 125I to give a specific activity of 0.041 muCi/mg) was prepared by the chloramine T method. It was active in two bioassays (pigeon crop sac and dispersed mouse mammary cell), though somewhat less active than the unmodified hormone. In an immunoassay, iodinated prolactin was more effective than the unmodified hormone at displacing 125I-prolactin from antibody. High specific activity 125I-prolactin (1 iodine atom/molecule; 70 muCi/microgram) was used for autoradiographic studies on the binding of prolactin to mouse mammary cells. In vivo the labelled hormone found in the mammary gland was associated with membranes of mammary epithelial cells and with alveolar lumen contents. In vitro 125I-prolactin was shown to bind to dispersed mouse mammary epithelial cells.

Amino Acids↗
PubMed1977

Actions of growth hormone, prolactin and thyroxine on serum somatomedin-like activity and growth in hypopituitary dwarf mice.

Hypopituitary dwarf mice (Snell's strain) were found to have much reduced levels of serum somatomedin when compared with normal mice (apparently normal members of the Snell strain). Treatment with bovine growth hormone, prolactin or thyroxine induced growth in these animals; this was accompanied in each case by increased levels of serum somatomedin (primarily somatomedin C). Growth hormone had a dose-dependent growth-promoting effect, but this was not reflected in dose-dependent increases in serum somatomedin levels. These results are in accordance with the concept that somatomedin is involved in the regulation of overall somatic growth, but it seems likely that other factors are also involved.

Animals↗
PubMed1973

Biosynthesis of growth hormone in the rat anterior pituitary gland. Stimulation of biosynthesis in vitro by insulin.

The effect of insulin on the incorporation of radioactive leucine into growth hormone was investigated by using rat anterior pituitary glands incubated in vitro. A 50% stimulation over control values was observed at insulin concentrations above 2mum (280munits/ml). The effect was specific for growth hormone biosynthesis, over the range 1-5mum-insulin (140-700munits/ml). Lower more physiological concentrations had no significant effect in this system. Above 10mum (1.4 units/ml) total protein synthesis was also increased. The stimulation of growth hormone synthesis could be partially blocked by the addition of actinomycin D, suggesting that RNA synthesis was involved. Insulin was found to stimulate the rate of glucose utilization in a similar way to growth hormone synthesis. 2-Deoxyglucose and phloridzin, which both prevented insulin from stimulating glucose utilization, also prevented the effect of insulin on growth hormone synthesis. If glucose was replaced by fructose in the medium, the effect of insulin on growth hormone synthesis was decreased. We conclude that the rate of utilization of glucose may be an important step in mediating the effect of insulin on growth hormone synthesis.

Animals↗