Observations on the Early Actions of Prolactin on RNA and Casein Synthesis in Mouse Mammary Gland Explants

1980 ◽  
Vol 12 (4) ◽  
pp. 218-223 ◽  
Author(s):  
J.A. Rillema ◽  
M. Schneider-Kuznia
Keyword(s):  
Mammary Gland ◽  
Mouse Mammary Gland ◽  
Casein Synthesis

scholarly journals The differential actions of cortisol on the synthesis and turnover of alpha-lactalbumin and casein and on accumulation of their mRNA in mouse mammary gland in organ culture

1983 ◽  
Vol 212 (2) ◽  
pp. 507-515 ◽  
Author(s):  
Y Nagamatsu ◽  
T Oka
Keyword(s):  
Mammary Gland ◽  
Marked Decrease ◽  
Milk Proteins ◽  
Mammary Glands ◽  
Mouse Mammary Gland ◽  
Marked Enhancement ◽  
Pregnant Mice ◽  
Translatable Mrna ◽  
Casein Synthesis ◽  
Alpha Lactalbumin

Cortisol was previously shown to exert different, concentration-dependent, effects on the accumulation of casein and alpha-lactalbumin in mammary glands from mid-pregnant mice cultured in the presence of insulin and prolactin [Ono & Oka (1980) Cell 19, 473-480]. The present study demonstrated that the addition of 30nM-cortisol to the medium containing insulin and prolactin resulted in a marked enhancement of the rate of synthesis of both alpha-lactalbumin and casein in cultured tissue. The addition of 3 microM-cortisol in combination with insulin and prolactin caused a marked decrease in the rate of alpha-lactalbumin synthesis, but increased casein synthesis substantially. Similar changes were also observed in the amount of translatable mRNA for alpha-lactalbumin and casein in mammary explants cultured with insulin, prolactin and the two concentrations of cortisol. The study of the turnover of the milk proteins in cultured explants showed that virtually all of the casein synthesized remained intact in tissue explants cultured with 3 microM cortisol, whereas about 45% of casein disappeared in 40h from explants cultured with 30nM-cortisol. In contrast, the two concentrations of cortisol did not differentially affect the disappearance of alpha-lactalbumin, which was about 55% in 40h. These results indicate that the concentration-dependent differential actions of cortisol on the accumulation of alpha-lactalbumin and casein are exerted through its effects on the rate of synthesis and turnover of the two proteins as well as on the accumulation of their mRNA species.

AN IN-VITRO BIOASSAY FOR PROLACTIN BASED ON STIMULATION OF CASEIN SYNTHESIS BY A DISPERSED CELL PREPARATION FROM MOUSE MAMMARY GLAND

1974 ◽  
Vol 62 (3) ◽  
pp. 463-472 ◽  
Author(s):  
W. A. BULLOUGH ◽  
M. WALLIS
Keyword(s):  
Mammary Gland ◽  
Response Curve ◽  
Mouse Mammary Gland ◽  
Placental Lactogen ◽  
Cell Preparation ◽  
In Vitro Bioassay ◽  
Mammary Gland Cells ◽  
Casein Synthesis ◽  
Stimulation Of

SUMMARY An in-vitro bioassay for prolactin has been devised, based on the stimulation of casein synthesis in a mouse mammary gland preparation. Dispersed mammary gland cells were superior to intact explants for this purpose. Casein synthesis by dispersed cells was stimulated by added prolactin, and a linear log dose—response curve was established (for the range 5–20 μg prolactin/ml). The precision of the assay was high (λ = 0·10–0·15). Sensitivity was rather low, but could be improved by increasing the concentration of amino acids in the medium. The response to prolactin was not influenced by thyroxine, adrenocorticotrophin or oestradiol, but thyrotrophin appeared to inhibit it slightly. Both human placental lactogen and bovine growth hormone showed lactogenic activity in the assay.

A BIOCHEMICAL COMPARISON OF THE LACTOGENIC EFFECT OF PROLACTIN AND GROWTH HORMONE ON MOUSE MAMMARY GLAND IN ORGAN CULTURE

1972 ◽  
Vol 52 (2) ◽  
pp. 349-NP ◽  
Author(s):  
D. Y. WANG ◽  
R. C. HALLOWES ◽  
R. H. SMITH ◽  
V. AMOR ◽  
D. J. LEWIS
Keyword(s):  
Growth Hormone ◽  
Mammary Gland ◽  
Organ Culture ◽  
Polyacrylamide Gel Electrophoresis ◽  
Intrinsic Property ◽  
Mouse Mammary Gland ◽  
Bovine Growth Hormone ◽  
Biochemical Comparison ◽  
Sites Of Action ◽  
Casein Synthesis

SUMMARY A biochemical comparison of the lactogenic effect of ovine prolactin and of bovine growth hormone on pregnant mouse mammary gland in organ culture was made. No qualitative differences were observed; both hormones (in the presence of insulin and corticosterone) stimulated the synthesis of casein and RNA in mouse mammary gland explants. The inhibition of RNA synthesis with actinomycin D was associated with a decrease in casein synthesis. However, quantitatively, prolactin was more efficient than growth hormone in stimulating casein synthesis. The synthesis of casein in mouse mammary gland explants incubated in the presence of various combinations of hormones gave results which suggested that prolactin and growth hormone are operating on the same sites of action. Analysis of, and purification by, polyacrylamide gel electrophoresis of the bovine growth hormone showed that the lactogenic effects were not due to the presence of prolactin as an impurity, but were an intrinsic property of the growth hormone.

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