Localization of carbonic anhydrase in the goat mammary gland during involution and lactogenesis

1998 ◽  
Vol 65 (1) ◽  
pp. 43-54 ◽  
Author(s):  
KATARINA CVEK ◽  
KRISTINA DAHLBORN ◽  
YVONNE RIDDERSTRÅLE
Keyword(s):  
Mammary Gland ◽  
Carbonic Anhydrase ◽  
Time Course ◽  
Ph Regulation ◽  
Late Pregnancy ◽  
Milk Composition ◽  
Tissue Growth ◽  
Systemic Factors ◽  
Membrane Bound ◽  
Alveolar Area

The aim of this study was to determine whether carbonic anhydrase (CA) activity in goat mammary capillaries is regulated mainly by local or systemic mechanisms. One gland was dried before the contralateral gland, and after parturition only one gland was milked. Biopsies were taken from the mammary glands of three goats at 14 d intervals during involution and the start of the following lactation. A histochemical method was used to visualize sites of CA activity. To follow the involution process, milk (liquid) samples were taken from both teats each week and analysed for pH and composition. The time course of CA activity disappearance and reappearance in the capillaries was related to changes in milk composition and alveolar area. A dense network of capillaries showing membrane-bound staining for CA was found surrounding the alveoli in the lactating gland. CA activity gradually decreased in the drying gland, although the other gland was being milked. After 8 weeks involution the dried gland had a significantly lower number of stained capillaries than the milked gland. Almost no stained capillaries were found during late pregnancy, when both glands were dried and the tissue growth maximal. During lactation milk pH was 6·6±0·3 and this increased to 7·0±0·1 in the course of involution. In the last trimester of pregnancy the pH returned to its lower value, while the mammary gland was devoid of stained capillaries. Therefore, the capillary CA could not have been directly involved in the pH regulation of milk. The CA activity reappeared in the capillaries directly after delivery, but only in the milked gland. Clearly the regulation of CA activity is influenced more by local than by systemic factors and is associated with the metabolic activity of milk secretion.

scholarly journals Mammary Gland Structures Are Not Affected by an Increased Growth Rate of Yearling Ewes Post-Weaning but Are Associated with Growth Rates of Singletons

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 884
Author(s):  
Emmanuelle Haslin ◽  
Rene A. Corner-Thomas ◽  
Paul R. Kenyon ◽  
Adrian J. Molenaar ◽  
Stephen T. Morris ◽  
...  
Keyword(s):  
Growth Rate ◽  
Mammary Gland ◽  
Live Weight ◽  
Late Pregnancy ◽  
Control Group ◽  
Early Lactation ◽  
Fat Pad ◽  
Negative Effects ◽  
Lamb Growth ◽  
Heavy Group

The experiment aimed to examine the impacts of an increased growth rate of ewes between three and seven months of age on udder development using ultrasound and to establish whether ultrasonography could be used to identify ewe mammary structures that may be indirect indicators of singleton growth to weaning. Udder dimensions, depths of gland cistern (GC), parenchyma (PAR) and fat pad (FP) were measured in late pregnancy (P107), early lactation (L29), and at weaning (L100) in 59 single-bearing yearling ewes selected from two treatments. The ‘heavy’ group (n = 31) was preferentially fed prior to breeding achieving an average breeding live-weight of 47.9 ± 0.38 kg at seven months of age. The ‘control’ group (n = 28) had an average breeding live-weight of 44.9 ± 0.49 kg. Udder dimensions, GC, PAR and FP did not differ between treatments. Lamb growth to L100 was positively associated (p < 0.05) with PAR at P107 and GC at L29. There was no evidence of negative effects of the live-weight gain treatments on udder development of yearling ewes as measured by ultrasonography. The results suggest that this ultrasound method has the potential to identify pregnant yearling ewes which would wean heavier singletons.

CHANGES IN THE COMPOSITION AND YIELD OF THE MAMMARY SECRETION OF COWS DURING THE INITIATION OF LACTATION

1973 ◽  
Vol 59 (2) ◽  
pp. 231-247 ◽  
Author(s):  
P. E. HARTMANN
Keyword(s):  
Mammary Gland ◽  
Late Pregnancy ◽  
The Other ◽  
Small Samples ◽  
Dry Period ◽  
Abrupt Increase ◽  
Milk Samples ◽  
Casein Protein ◽  
Two Phases

SUMMARY Mammary secretion (1·2–2·0 ml) was collected from the milk sinus of each mammary gland (quarter) of two pregnant heifers and eight pregnant cows (dry period 49–229 days), first at weekly intervals from 40 days before parturition, then with increasing frequency as parturition approached. The progressive changes in the concentration of lactose, glucose, casein, non-casein protein and fat in the mammary secretion were determined. Calves were separated from the cows immediately after birth and the yield and composition of milk from individual quarters were determined for 5 days after parturition. Two quarters (milked quarters) of each of a further five cows were milked throughout pregnancy, while the other two quarters (unmilked quarters) of each cow were allowed to involute (dry off) 63– 104 days before parturition. Small samples (5–10 ml) of secretion were collected from the unmilked quarters, first at weekly intervals after drying off and then every second day from 10 to 15 days before parturition. On the days that the unmilked quarters were sampled, corresponding composite milk samples were collected from the milked quarters and the progressive changes in the yield of milk, lactose and fat were determined. The changes in the concentration of lactose and glucose in the mammary secretion, during drying off in late lactation, were determined in an additional five cows. In most cows allowed a usual dry period, and in the unmilked quarters of cows in which two quarters were milked throughout pregnancy, the concentration of lactose gradually increased from about 8 to 12 days before parturition to reach levels of about half those found in normal milk just before parturition. However, in some cows the concentration of lactose was low until 1–2 days before parturition and then increased abruptly, whereas in others the concentration of lactose increased slowly from as early as 32 days before parturition. A further rapid increase in the concentration of lactose in the mammary secretion occurred between 0 and 4 days before parturition in all cows. This latter increase was accompanied by an abrupt increase in the yield of milk, lactose and fat in the milked quarters of the cows in which two quarters were milked throughout pregnancy. These observations suggest that the initiation of lactation in the cow develops in two phases, a limited secretion of milk constituents occurs in late pregnancy and then 0–4 days before parturition copious secretion (lactogenesis) occurs.

scholarly journals Englitazone administration to late pregnant rats produces delayed body growth and insulin resistance in their fetuses and neonates

2005 ◽  
Vol 389 (3) ◽  
pp. 913-918 ◽  
Author(s):  
Julio Sevillano ◽  
Inmaculada C. López-Pérez ◽  
Emilio Herrera ◽  
María del Pilar Ramos ◽  
Carlos Bocos
Keyword(s):  
Body Mass ◽  
Control Cell ◽  
Late Pregnancy ◽  
Tissue Growth ◽  
Peroxisome Proliferator ◽  
Pregnant Rats ◽  
Peroxisome Proliferator Activated Receptor ◽  
Akt Phosphorylation ◽  
Insulin Resistant

The level of maternal circulating triacylglycerols during late pregnancy has been correlated with the mass of newborns. PPARγ (peroxisome-proliferator-activated receptor γ) ligands, such as TZDs (thiazolidinediones), have been shown to reduce triacylglycerolaemia and have also been implicated in the inhibition of tissue growth and the promotion of cell differentiation. Therefore TZDs might control cell proliferation during late fetal development and, by extension, body mass of pups. To investigate the response to EZ (englitazone), a TZD, on perinatal development, 0 or 50 mg of englitazone/kg of body mass was given as an oral dose to pregnant rats daily from day 16 of gestation until either day 20 for the study of their fetuses, or until day 21 of gestation for the study of neonates. EZ decreased maternal triacylglycerol levels at day 20 of gestation and neonatal mass, but not fetal mass. Fetuses and neonates from EZ-treated mothers exhibited high levels of insulin and were found to be hyperglycaemic. The apparent insulin-resistant state in neonates from EZ-treated pregnant rats was corroborated, since they showed higher plasma NEFA [non-esterified (‘free’) fatty acid] levels, ketonaemia and liver LPL (lipoprotein lipase) activity and lower plasma IGF-I (type 1 insulin-like growth factor) levels, in comparison with those from control mothers. Moreover, at the molecular level, an increase in Akt phosphorylation was found in the liver of neonates from EZ-treated mothers, which confirms that the insulin pathway was negatively affected. Thus the response of fetuses and neonates to maternal antidiabetic drug treatment is the opposite of what would be expected, and can be justified by the scarce amount of adipose tissue impeding a normal response to PPARγ ligands and by hyperinsulinaemia as being responsible for a major insulin-resistant condition.

Differential patterns of transcript accumulation during human myogenesis

1987 ◽  
Vol 7 (11) ◽  
pp. 4100-4114
Author(s):  
P Gunning ◽  
E Hardeman ◽  
R Wade ◽  
P Ponte ◽  
W Bains ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Carbonic Anhydrase ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Time Course ◽  
Human Skeletal Muscle ◽  
Transcript Accumulation ◽  
Mrna Accumulation ◽  
Adult Human ◽  
Alpha Actin

We evaluated the extent to which muscle-specific genes display identical patterns of mRNA accumulation during human myogenesis. Cloned satellite cells isolated from adult human skeletal muscle were expanded in culture, and RNA was isolated from low- and high-confluence cells and from fusing cultures over a 15-day time course. The accumulation of over 20 different transcripts was compared in these samples with that in fetal and adult human skeletal muscle. The expression of carbonic anhydrase 3, myoglobin, HSP83, and mRNAs encoding eight unknown proteins were examined in human myogenic cultures. In general, the expression of most of the mRNAs was induced after fusion to form myotubes. However, several exceptions, including carbonic anhydrase and myoglobin, showed no detectable expression in early myotubes. Comparison of all transcripts demonstrated little, if any, identity of mRNA accumulation patterns. Similar variability was also seen for mRNAs which were also expressed in nonmuscle cells. Accumulation of mRNAs encoding alpha-skeletal, alpha-cardiac, beta- and gamma-actin, total myosin heavy chain, and alpha- and beta-tubulin also displayed discordant regulation, which has important implications for sarcomere assembly. Cardiac actin was the only muscle-specific transcript that was detected in low-confluency cells and was the major alpha-actin mRNA at all times in fusing cultures. Skeletal actin was transiently induced in fusing cultures and then reduced by an order of magnitude. Total myosin heavy-chain mRNA accumulation lagged behind that of alpha-actin. Whereas beta- and gamma-actin displayed a sharp decrease after initiation of fusion and thereafter did not change, alpha- and beta-tubulin were transiently induced to a high level during the time course in culture. We conclude that each gene may have its own unique determinants of transcript accumulation and that the phenotype of a muscle may not be determined so much by which genes are active or silent but rather by the extent to which their transcript levels are modulated. Finally, we observed that patterns of transcript accumulation established within the myotube cultures were consistent with the hypothesis that myoblasts isolated from adult tissue recapitulate a myogenic developmental program. However, we also detected a transient appearance of adult skeletal muscle-specific transcripts in high-confluence myoblast cultures. This indicates that the initial differentiation of these myoblasts may reflect a more complex process than simple recapitulation of development.

Time course of exchanges between red cells and extracellular fluid during CO2 uptake

1975 ◽  
Vol 38 (4) ◽  
pp. 710-718 ◽  
Author(s):  
R. E. Forster ◽  
E. D. Crandall
Keyword(s):  
Carbonic Anhydrase ◽  
Time Course ◽  
Extracellular Fluid ◽  
Extracellular Ph ◽  
Co2 Uptake ◽  
Sudden Increase ◽  
Red Cell ◽  
Ph Change ◽  
Red Cell Membrane

A stopped-flow rapid-reaction apparatus was used to follow the time course of extracellular pH in a human red cell suspension following a sudden increase in PCO2. The extracellular pH change was slow (t1/2 similar to 3.5 s) considering the presence of carbonic anhydrase in the cells. When carbonic anhydrase was added to the extracellular fluid, the half-time was reduced to less than 20 ms. The explanation for these phenomena is that the equilibration of H+ across the red cell membrane is rate-limited by the uncatalyzed reaction CO2 plus H2O formed from H2CO3 outside the cells. A theoretical model was developed which successfully reproduced the experimental results. When the model was used to simulate CO2 exchange in vivo, it was determined that blood PCO2 and pH require long times (greater than 50 s) to approach equilibrium between cells and plasma after leaving an exchange capillary. We conclude that cell-plasma equilibrium may never be reached in vivo, and that in vitro measurements of these quantities may not represent their true values at the site of sampling.

Expression of membrane-bound carbonic anhydrase in developing human lung and kidney

1989 ◽  
Vol 17 (6) ◽  
pp. 1122-1123
Author(s):  
NICK CARTER ◽  
ANTHONY FRYER ◽  
ROBERT HUME ◽  
RICHARD STRANGE ◽  
PER WISTRAND
Keyword(s):  
Carbonic Anhydrase ◽  
Human Lung ◽  
Membrane Bound ◽  
Lung And Kidney

Protein utilisation by the mammary gland in lactating dairy cows

1992 ◽  
Vol 1992 ◽  
pp. 1-1 ◽  
Author(s):  
J A Metcalf ◽  
D E Beever ◽  
J D Sutton ◽  
D J Humphries
Keyword(s):  
Mammary Gland ◽  
Dry Matter ◽  
Milk Composition ◽  
Protein Levels ◽  
Lactating Cows ◽  
Lactating Dairy Cows ◽  
Milk Output ◽  
Underlying Mechanisms ◽  
Protein Supply ◽  
Friesian Cows

Milk output has been manipulated by dietary methods for many years, however the underlying mechanisms for changes in milk composition are as yet unclear. In an attempt to further understand these mechanisms we have compared the mammary uptake of metabolites on two isoenergetic diets with different protein levels expected to provide different amounts of amino acid to the mammary gland.Early- to mid-lactation Friesian cows were used to examine the effect of increased dietary protein supply on the supply of metabolites to and uptake by the mammary gland in relation to milk protein synthesis. Two barley based concentrates were formulated to contain 20.8 (Cl) or 29.1 (C2) g N/kg DM, using fishmeal (Provimi 66, high UDP) as the supplementary protein and fed with grass silage (28.3 g N/kg DM) at a total dry matter intake of 17 kg/day. In Experiment 1 these diets were fed at 50:50 (concentrate:silage) to four lactating cows fitted with rumen and duodenal cannulae in a simple crossover design.

Mammary gland cell content during various phases of lactation

1962 ◽  
Vol 203 (5) ◽  
pp. 939-941 ◽  
Author(s):  
Richard C. Moon
Keyword(s):  
Mammary Gland ◽  
Deoxyribonucleic Acid ◽  
Cellular Proliferation ◽  
Gland Cell ◽  
Late Pregnancy ◽  
Mammary Glands ◽  
Lactation Period ◽  
Cell Content ◽  
Rat Mammary Gland ◽  
Mammary Gland Cell

Deoxyribonucleic acid (DNA) was used as an index of the cellular state of the rat mammary gland in late pregnancy ( day 20) and early ( day 1), intense ( day 14), and declining ( day 28) lactation. Dams sacrificed on day 28 of lactation were provided with foster litters on day 14 postpartum to insure a strong sucking stimulus during the lactation period from days 14–28. Mammary DNA increased 57% from day 20 of pregnancy to lactation day 14, but no significant change in DNA content was evident by day 1 of lactation. A significantly lower DNA concentration was observed in mammary glands of rats sacrificed at lactation day 28 when compared with that of animals killed at day 14 of lactation. The data suggest that cellular proliferation of mammary gland continues well into lactation and that a decline in lactation may be due, in part, to a reduction in the number of milk-secreting cells.

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