scholarly journals Initiation of fatty acid synthesis in rat mammary glands

1980 ◽  
Vol 190 (1) ◽  
pp. 171-175 ◽  
Author(s):  
P Martyn ◽  
I A Hansen
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Post Partum ◽  
Acid Synthesis ◽  
Mammary Glands ◽  
Mammary Tissue ◽  
Lactose Synthesis

The rate of fatty acid synthesis from [6-14C]glucose in mammary tissue remained low until parturition at 22 days of gestation and increased 10-fold at 1 day post partum. Administration of progesterone on days 20 and 21 or removal of pups at parturition abolished this increase. In the latter case, administration of prolactin, corticosterone or oxytocin had no stimulatory effect; tissue from suckled glands in which the ducts had been ligated at parturition also showed no increased rate in 24 h. Foetoplacentectomy on day 18 did not stimulate fatty acid synthesis but subsequent suckling by foster pups did. Whereas lactose synthesis is initiated by withdrawal of progesterone from the circulation, a further stimulus related to removal of milk by suckling is required to initiate fatty acid synthesis.

scholarly journals Metabolic adaptations during lactogenesis. Fatty acid and lactose synthesis in cow mammary tissue

1973 ◽  
Vol 136 (3) ◽  
pp. 741-748 ◽  
Author(s):  
R. W. Mellenberger ◽  
D. E. Bauman ◽  
D. R. Nelson
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Post Partum ◽  
Acid Synthesis ◽  
Mammary Tissue ◽  
Acetate Incorporation ◽  
Acetyl Coa Carboxylase ◽  
Tissue Slices ◽  
Acetyl Coa ◽  
Lactose Synthesis

1. Mammary-tissue biopsies were obtained from multiparous cows at 30 and 7 days pre partum and 7 and 40 days post partum. Investigations of the effect of lactogenesis on fatty acid and lactose synthesis involved measurements of biosynthetic capacity (tissue-slice incubations in vitro) and activities of relevant enzymes. 2. Fatty acid synthesis from acetate increased over 20-fold from 30 days pre partum to 40 days post partum. Changes in the lipogenic capacity of mammary-tissue slices more closely paralleled increases in the activities of acetyl-CoA carboxylase (EC 6.4.1.2) and acetyl-CoA synthetase (EC 6.2.1.1) than of other enzymes involved in acetate incorporation into fatty acids or in NADPH generation. 3. Lactose biosynthesis by mammary-tissue slices, lactose synthetase activity (EC 2.4.1.22) and α-lactalbumin concentration were all negligible at 30 days pre partum but increased 2.5–4-fold between 7 days pre partum and 40 days post partum. Phosphoglucomutase (EC 2.7.5.1), UDP-glucose pyrophosphorylase (EC 2.7.7.9) and UDP-glucose 4-epimerase (EC 5.1.3.2) had substantial activities at 30 days pre partum and increased less dramatically during lactogenesis. 4. Results are consistent with acetyl-CoA carboxylase and perhaps acetyl-CoA synthetase representing the regulatory enzyme(s) in fatty acid synthesis, with lactose synthetase (α-lactalbumin) serving a similar function in lactose biosynthesis.

Fatty acid synthesis by explant cultures from the mammary glands of goats on days 60 and 120 of pregnancy

1984 ◽  
Vol 100 (1) ◽  
pp. 87-NP ◽  
Author(s):  
I. A. Forsyth ◽  
A. Turvey
Keyword(s):  
Fatty Acid ◽  
Epithelial Cells ◽  
Fatty Acid Synthesis ◽  
Milk Fat ◽  
Secretory Activity ◽  
Acid Synthesis ◽  
Mammary Glands ◽  
Mammary Tissue ◽  
Histological Structure ◽  
Fourfold Increase

ABSTRACT Explants of mammary glands from 60-day pregnant goats showed a mean fourfold increase in fatty acid synthesis from acetate when cultured with insulin+ cortisol. Epithelial cells increased their area by 60% but no secretory activity was induced. In 120-day pregnant goats, fatty acid synthesis and epithelial cell area were greater than at day 60 of pregnancy and were unaffected by hypophysectomy or by daily treatment with bromocriptine from day 60. Neither increased further on culture of mammary explants in insulin + cortisol. Ovine prolactin increased fatty acid synthesis two-fold when added to insulin + cortisol in cultures of mammary tissue from goats on day 60 of pregnancy and secretory activity was induced. On day 120 of pregnancy insulin + cortisol + prolactin sustained or slightly stimulated both fatty acid synthesis and the extensive secretion present in the tissue at the start of culture. Synthesis of medium-chain fatty acids of milk-fat was also sustained by prolactin in one goat. An atmosphere of air was found to maintain normal histological structure of the mammary gland. By contrast, in 95% oxygen, explants from goats which were 60 days pregnant showed epithelial cells filling the lumina of ducts and alveoli in 60% of explants and a poor response to prolactin. J. Endocr. (1984) 100, 87–92

scholarly journals The effect of progesterone on prolactin stimulation of fatty acid synthesis, glycerolipid synthesis and lipogenic-enzyme activities in mammary glands of pseudopregnant rabbits, after explant culture or intraductal injection

1985 ◽  
Vol 231 (2) ◽  
pp. 321-328 ◽  
Author(s):  
P Martyn ◽  
I R Falconer
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Fatty Acid Synthetase ◽  
Acid Synthesis ◽  
Mammary Glands ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Physiological Concentration ◽  
Intraductal Injection ◽  
Glycerolipid Synthesis

The activities of lipogenic enzymes, such as acetyl-CoA carboxylase, fatty acid synthetase and glucose-6-phosphate dehydrogenase, and glycerolipid synthesis increased significantly in mammary explants of 11-day-pseudopregnant rabbits in response to prolactin, in the presence of near-physiological concentrations of insulin and corticosterone in culture. Increasing the concentration of progesterone in culture resulted in suppression of glycerolipid synthesis and activities of acetyl-CoA carboxylase and fatty acid synthetase, but not the pentose phosphate dehydrogenases. However, at near-physiological concentration of progesterone, only acetyl-CoA carboxylase activity was decreased. Injection of prolactin intraductally into 11-day-pseudopregnant rabbits stimulated glycerolipid synthesis, fatty acid synthesis and enzymes involved in fatty acid synthesis, after 3 days. Intraductal injection of progesterone separately or together with prolactin had no significant effect on basal or stimulated lipogenesis in mammary glands. Intramuscular injection of progesterone at 10 mg/day did not suppress fatty acid synthesis stimulated when prolactin was injected intraductally, but a significant inhibition was observed at a higher dose (80 mg/day).

Assessment of mammary gland metabolism in the sow: II. Cellular metabolites in the mammary secretion and plasma during lactogenesis II

1995 ◽  
Vol 62 (2) ◽  
pp. 207-220 ◽  
Author(s):  
Craig S. Atwood ◽  
Janine K. Toussaint ◽  
Peter E. Hartmann
Keyword(s):  
Mammary Gland ◽  
Metabolic Activity ◽  
Inorganic Phosphate ◽  
De Novo ◽  
Post Partum ◽  
Acid Synthesis ◽  
Mammary Glands ◽  
Progressive Increase ◽  
Progressive Decrease ◽  
Lactose Synthesis

SUMMARYThe concentrations of lactose, glucose, glucose 6-phosphate, glucose 1-phosphate, UDPglucose, UDPgalactose, UDP, UMP, inorganic phosphate, ADP and AMP (metabolites involved in the lactose synthesis pathway), and cAMP, galactose and fructose were measured in the mammary secretion from sucked (n = 9) and unsucked (n = 4) mammary glands of nine sows during the first 5 d post partum. The concentrations of lactose, glucose, galactose and fructose were also measured in plasma during this time. The progressive increase in the concentration of lactose, and changes in the concentrations of cellular metabolites in the mammary secretion from sucked glands were consistent with an increase in the metabolic activity of those glands during lactogenesis II. In contrast, unsucked glands showed a progressive decrease in the concentration of lactose, while the concentrations of cellular metabolites in the milk generally remained unchanged. These results indicated that there was no increase in the metabolic activity of unsucked glands (no increase in lactose synthesis or utilization of glucose and ATP) and that the rate of lactose synthesis prior to milk removal was limited by the availability of glucose and/or UDPgalactose. Therefore, the removal of colostrum from the mammary gland was necessary for an increase in the rate of lactose synthesis (and probably de novo fatty acid synthesis) and implies that autocrine mechanisms are operating to control the rate of milk synthesis during lactogenesis in the sow. The low concentration of glucose in colostrum compared with that in plasma is discussed in view of the paracellular pathway.

scholarly journals Fatty Acid Synthesis in Sheep Mammary Tissue

1973 ◽  
Vol 56 (10) ◽  
pp. 1312-1318 ◽  
Author(s):  
D.E. Bauman ◽  
R.W. Mellenberger ◽  
R.G. Derrig
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Acid Synthesis ◽  
Mammary Tissue

scholarly journals Metabolic adaptations during lactogenesis. Fatty acid synthesis in rabbit mammary tissue during pregnancy and lactation

1974 ◽  
Vol 138 (3) ◽  
pp. 373-379 ◽  
Author(s):  
R. W. Mellenberger ◽  
D. E. Bauman
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Acid Synthesis ◽  
Co2 Production ◽  
Mammary Tissue ◽  
Atp Citrate Lyase ◽  
Acetyl Coa ◽  
Citrate Lyase ◽  
Pregnancy And Lactation ◽  
Synthetic Capacity

1. Mammary tissue was obtained from rabbits at various stages of pregnancy and lactation and used for tissue-slice incubations (to measure the rate of fatty acid synthesis and CO2 production) and to determine relevant enzymic activities. A biphasic adaptation in fatty acid synthetic capacity during lactogenesis was noted. 2. The first lactogenic response occurred between day 15 and 24 of pregnancy. Over this period fatty acid synthesis (from acetate) increased 14-fold and the proportions of fatty acids synthesized changed to those characteristic of milk fat (77–86% as C8:0+C10:0 acids). 3. The second lactogenic response occurred post partum as indicated by increased rates of fatty acid synthesis and CO2 production (from acetate and glucose) and increased enzymic activities. 4. Major increases in enzymic activities between mid-pregnancy and lactation were noted for ATP citrate lyase (EC 4.1.3.8), acetyl-CoA synthetase (EC 6.2.1.1), acetyl-CoA carboxylase (EC 6.4.1.2), fatty acid synthetase, glucose 6-phosphate dehydrogenase (EC 1.1.1.49), and 6-phosphogluconate dehydrogenase (EC 1.1.1.44). Smaller increases in activity occurred with glycerol 3-phosphate dehydrogenase (EC 1.1.1.8) and NADP+–isocitrate dehydrogenase (EC 1.1.1.42) and the activity of NADP+–malate dehydrogenase (EC 1.1.1.40) was negligible at all periods tested. 5. During pregnancy and lactation there was a close temporal relationship between fatty acid synthetic capacity and the activities of ATP citrate lyase (r=0.94) and acetyl-CoA carboxylase (r=0.90).

scholarly journals Cellular Studies of Mammary Tissue from Cows Hormonally Induced into Lactation: Lactose and Fatty Acid Synthesis

1976 ◽  
Vol 59 (7) ◽  
pp. 1226-1231 ◽  
Author(s):  
R.J. Collier ◽  
W.J. Croom ◽  
D.E. Bauman ◽  
R.L. Hays ◽  
D.R. Nelson
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Acid Synthesis ◽  
Mammary Tissue

Mammary gland enzyme systems in the study of fatty-acid synthesis

1958 ◽  
Vol 149 (936) ◽  
pp. 414-420
Keyword(s):  
Fatty Acids ◽  
Mammary Gland ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Short Chain Fatty Acids ◽  
Acid Synthesis ◽  
Short Chain ◽  
Mammary Tissue ◽  
Lactating Mammary Gland ◽  
Chain Fatty Acids

1. Introduction: The role of acetate in fatty-acid synthesis In 1945 Folley and his colleagues (see Foiley 1949, 1952; Malpress 1946) suggested that, in the ruminant, short-chain fatty acids might be synthesized by the lactating mammary gland from acetate. These short-chain fatty acids might then serve as precursors for the synthesis of long-chain acids. Folley & French (1949, 1950) showed that in vitro slices of lactating ruminant mammary gland were able to synthesize fat from acetate, as indicated by a respiratory quotient greater than unity. Non-ruminant lactating mammary tissue was unable to do so, but could utilize glucose for fat synthesis. It was later shown, with the aid of tracers (Balmain, Folley & Glascock 1954) that non-ruminant lactating mammary gland slices could use acetate for the synthesis of fat, provided that glucose was also added. Experiments in vivo laid emphasis upon the synthesis of short-chain fatty acids by the mammary gland. Popják & Beeckmans (1950) showed that injection of [ carboxy - 14 C]acetate into the pregnant rabbit gave rise to a high degree of labelling in the mammary gland fat. Fractionation of these fatty acids (Popják, Folley & French 1950) showed that the label was predominantly concentrated in the short-chain fatty acids, and that this labelling was far higher than that found in the liver fatty acids, indicating synthesis in the gland itself.

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