Reductions of Nitro and 9-Oxo Groups of Environmental Nitrofluorenes by the Rat Mammary Gland in Vitro

2000 ◽  
Vol 13 (8) ◽  
pp. 793-800 ◽  
Author(s):  
Clare L. Ritter ◽  
Richard W. Decker ◽  
Danuta Malejka-Giganti
Keyword(s):  
Mammary Gland ◽  
Rat Mammary Gland

scholarly journals Phosphoribosyl pyrophosphate and phosphoribosyl pyrophosphate synthetase in rat mammary gland. Changes in the lactation cycle and effects of diabetes, insulin and phenazine methosulphate

1986 ◽  
Vol 238 (2) ◽  
pp. 553-559 ◽  
Author(s):  
S Kunjara ◽  
M Sochor ◽  
N Salih ◽  
P McLean ◽  
A L Greenbaum
Keyword(s):  
Mammary Gland ◽  
Fold Increase ◽  
Pentose Phosphate ◽  
Diabetic Rat ◽  
Synthetase Activity ◽  
Phosphoribosyl Pyrophosphate ◽  
Rat Mammary Gland ◽  
Lactation Cycle ◽  
Phenazine Methosulphate

Changes in the tissue content of phosphoribosyl pyrophosphate (PPRibP), glucose 6-phosphate, ribose 5-phosphate (Rib5P), RNA and DNA, of the activity of PPRibP synthetase (EC 2.7.6.1) and the conversion of [1-14C]- and [6-14C]-glucose into 14CO2 were measured at mid-lactation in the normal and diabetic rat and in pregnancy, lactation and mammary involution in the normal rat. The PPRibP, glucose 6-phosphate and Rib5P contents increase during pregnancy and early lactation to reach a plateau value at mid-lactation, before falling sharply during weaning. The PPRibP content, PPRibP synthetase activity and flux of glucose through the oxidative pentose phosphate pathway (PPP) all change in parallel during the lactation cycle. Similarly, after 3 and 5 days duration of streptozotocin-induced diabetes, ending on day 10 of lactation, there were parallel declines in PPRibP content, PPRibP synthetase and PPP activity. The effect of streptozotocin was prevented by pretreatment with nicotinamide and partially reversed by insulin administration. Addition of insulin to lactating rat mammary-gland slices incubated in vitro significantly raised the PPRibP content (+47%) and the activity of the PPP (+40%); phenazine methosulphate, which gives a 2-fold increase in PPP activity, raised the PPRibP content of lactating mammary gland slices by approx. 3-fold. It is concluded that Rib5P, generated in the oxidative segment of the PPP, is an important determinant of PPRibP synthesis in the lactating rat mammary gland and that insulin plays a central role in the regulation of the bioavailability of this precursor of nucleotide and nucleic acid synthesis.

scholarly journals Rapid inhibition of lipogenesis in vivo in lactating rat mammary gland by medium- or long-chain triacylglycerols and partial reversal by insulin

1980 ◽  
Vol 192 (1) ◽  
pp. 361-364 ◽  
Author(s):  
L Agius ◽  
D H Williamson
Keyword(s):  
Mammary Gland ◽  
Glucose Utilization ◽  
Insulin Administration ◽  
Hepatic Lipogenesis ◽  
Medium Chain ◽  
Rat Mammary Gland ◽  
Long Chain ◽  
Partial Reversal

An intragastric load of medium- or long-chain triacylglycerols inhibited lipogenesis in lactating rat mammary gland in vivo by 82 or 89% respectively. This inhibition was reversed partially by insulin administration. Long-chain triacylglycerols inhibited hepatic lipogenesis in vivo but medium-chain triacylglycerols increased it 2-fold. Glucose utilization in vitro by mammary gland acini from triacylglycerol-fed rat was normal.

BREAKDOWN OF [3H]OXYTOCIN BY RAT TISSUES IN VITRO

1973 ◽  
Vol 59 (2) ◽  
pp. 305-312
Author(s):  
SANDRA M. EGAN ◽  
A. LIVINGSTON
Keyword(s):  
Skeletal Muscle ◽  
Mammary Gland ◽  
Incubation Medium ◽  
Rat Tissues ◽  
Tissue Uptake ◽  
Tissue Extracts ◽  
Rat Mammary Gland

SUMMARY Tissue uptake of oxytocin by rat mammary gland, uterus, heart and skeletal muscle was demonstrated by incubation of these tissues with 3H-labelled oxytocin. Chromatography of tissue extracts showed that some breakdown of oxytocin had occurred after only 30 s. However, in all cases there was no breakdown of oxytocin in the corresponding incubation medium. This indicated that the breakdown of oxytocin occurred within the tissues.

scholarly journals Effect of Puromycin in vitro on the Phosphorylation of Precursor Protein in Lactating Rat Mammary-Gland Slices

1967 ◽  
Vol 104 (3) ◽  
pp. 48C-50C ◽  
Author(s):  
Vishwa nath Singh ◽  
S. S. Dave ◽  
T. A. Venkitasubramanian
Keyword(s):  
Mammary Gland ◽  
Precursor Protein ◽  
Rat Mammary Gland
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