共查询到8条相似文献,搜索用时 0 毫秒
1.
J. E. Mellish S. J. Iverson W. D. Bowen M. O. Hammill 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1999,169(6):377-390
Hooded seals (Cystophora cristata) lactate for 3.6 days during which females simultaneously fast and transfer large amounts of energy to their pups through
fat-rich milk. Pups grow rapidly, principally due to blubber deposition. Lipoprotein lipase (LPL), the primary enzyme responsible
for tissue uptake of triglyceride fatty acids, may strongly influence both maternal milk fat secretion and pup blubber deposition.
We measured the energetic costs of lactation (using hydrogen isotope dilution, 3H20), milk composition, prolactin, and LPL activity (post-heparin plasma LPL [PH LPL], blubber, mammary gland and milk; U) in
six females. PH LPL and blubber LPL were measured in their pups. Females depleted 216.3 MJ · day−1 of body energy and fat accounted for 59% of maternal mass loss and 90% of postpartum body energy loss, but maternal body
composition changed little. Maternal blubber LPL was negligible (0.0–0.2 U), while mammary LPL was elevated (1.8–2.5 U) and
was paralleled by changes in prolactin. Estimated total mammary LPL activity was high (up to 20,000 U · animal−1) effectively favoring the mammary gland for lipid uptake. Levels of total blubber LPL in pups increased seven-fold over lactation.
Pups with higher PH LPL at birth had greater relative growth rates (P = 0.025). Pups with greater blubber stores and total blubber LPL activity had elevated rates of fat deposition (P = 0.035).
Accepted: 4 May 1999 相似文献
2.
L.L. Sun L. Liu J.T. Brenna Z.H. Wu L. Ma D.P. Bu 《Animal : an international journal of animal bioscience》2022,16(6):100545
Dairy products are the major source of odd- and branched-chain fatty acids (OBCFAs), a group of nutrients with emerging health benefits. The animal diet is known to influence milk fat OBCFAs of dairy cows; however, little is known about the effects of physiological factors. The objective of this study was to investigate the effects of parity and lactation stage on OBCFAs in milk fat of dairy cows. Holstein dairy cows (n = 157) were selected according to parity (first, second, third, or greater) and days in milk (DIM) (≤21 DIM, 21 < DIM ≤ 100, 100 < DIM ≤ 200, >200 DIM). All cows were fed the same total mixed ration for three weeks. Milk samples were collected during the last three days of each lactation stage for fatty acid (FA) analyses via gas chromatography. Results showed that first- and second-parity cows displayed significantly higher proportions and yields of iso-14:0, iso-15:0, iso-16:0, total iso-FA, and total branched-chain FA (P < 0.05) compared with other parities. The proportions of C17:0 and C17:1 cis-9 were also greater in first-parity cows (P < 0.05), while the yields of C17:0 and C17:1 cis-9 were similar among different parities (P > 0.05). The proportions of total OBCFAs were greater in first- and second-parity cows (P < 0.05), whereas the highest yield was observed in second-parity cows. Lactation dairy cows in ≤ 21 DIM group displayed lower proportions of iso-13:0, anteiso-13:0, C13:0, iso-14:0, C15:0, iso-16:0, total iso-FA, and total OBCFAs compared with that of the other groups (P < 0.05), and also lower yields of iso-14:0 and iso-16:0 (P < 0.05). In contrast, C17:0 and C17:1 cis-9 proportions and yields were higher in dairy cows with ≤ 21 DIM (P < 0.05). Iso-17:0 and anteiso-17:0 were not affected by lactation stage (P > 0.05). Taken together, our data showed that both parity and lactation stage have considerable effects on milk fat OBCFAs of dairy cows. In summary, first- and second-parity cows had higher milk OBCFAs compared with later parity cows, and OBCFAs with medium chain lengths were lower in dairy cows with ≤ 21 DIM, while C17:0 and C17:1 cis-9 were higher. These findings show that milk OBCFA contents are differentially modulated by physiological state. They will be useful in future studies that seek to alter OBCFA composition of Holstein dairy cow milk fats. 相似文献
3.
Martín-Hidalgo A Huerta L Alvarez N Alegría G Del Val Toledo M Herrera E 《Journal of lipid research》2005,46(4):658-668
We examined the presence of hormone-sensitive lipase (HSL) in mammary glands of virgin, pregnant (12, 20, and 21 days), and lactating (1 and 4 days postpartum) rats. Immunohistochemistry with antibody against rat HSL revealed positive HSL in the cytoplasm of both alveolar epithelial cells and adipocytes. In virgin rats, immunoreactive HSL was observed in mammary adipocytes, whereas diffuse staining was found in the epithelial cells. Positive staining for HSL was seen in the two types of cells in pregnant and lactating rats. However, as pregnancy advanced, the staining intensity of immunoreactive HSL increased in the epithelial cells parallel to their proliferation, attaining the maximum during lactation. An immunoreactive protein of 84 kDa and a HSL mRNA of 3.3. kb were found in the rat mammary gland as in white adipose tissue. Both HSL protein and activity were lower in mammary glands from 20 and 21 day pregnant rats than from those of virgin rats, although they returned to virgin values on days 1 and 4 of lactation. Mammary gland HSL activity correlated negatively to plasma insulin levels. Immunoreactive HSL and HSL activity were found in lactating rats' milk. The observed changes indicate an active role of HSL in mammary gland lipid metabolism. 相似文献
4.
Raphael N. Melmed Gideon Friedman Tova Chajek-Shaul Olga Stein Yechezkiel Stein 《Biochimica et Biophysica Acta (BBA)/Molecular Cell Research》1983,762(1):58-66
Three macrophage cell lines, J7742, CT2 and J7H1 were compared with respect to synthesis and secretion of lipoprotein lipase. The enzyme activity measured was characterized as lipoprotein lipase on the basis of serum dependence and inhibition by 1 M NaCl. Enzyme activity in all three lines increased with time in culture and the highest activity was found in the medium of the CT2 line which is adenylate cyclase deficient while that in the J7H1 line, cyclic AMP-dependent protein kinase deficient, was intermediate. The half life of the enzyme activity in conditioned medium from all three lines was 30–40 min, suggesting that the different levels of activity observed do represent different levels of enzyme production by the cells. About 80% of the lipoprotein lipase activity from all three lines was present in the medium and 50–70% of cellular activity could be released into the medium by a 3-min exposure to heparin. In addition, 24 h incubation with heparin enhanced enzyme secretion in all three lines. To determine the role of cyclic AMP in the regulation of lipoprotein lipase activity use was made of dibutyryl cAMP, methyl isobutylxanthine (IBMX) and cholera toxin. These agents strikingly depressed lipoprotein lipase activity in the J7742 line but only dibutyryl cAMP was active in the CT2 line (adenylate cyclase deficient). In the J7H1 (protein kinase deficient) line there was no response to dibutyryl cAMP or IBMX over the first 4 h of incubation. Addition of these agents did not affect total cell protein synthesis. The present findings indicate that in the intact cells changes in cyclic AMP levels are associated with a change in the activity of lipoprotein lipase. 相似文献
5.
6.
Yeonhwa Park Michael W Pariza 《Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids》2001,1534(1):27-33
The t10c12 isomer of conjugated linoleic acid (CLA) reduces lipid accumulation in adipocytes in part by inhibiting heparin-releasable lipoprotein lipase (LPL) activity. We now show that inhibitors of lipoxygenase (LOX) activity (2-[12-hydroxydodeca-5,10-diynyl]-3,5,6-trimethyl-p-benzoquinone; 5,8,11,14-eicosatetraynoic acid; salicylhydroxamic acid; indomethacin; nordihydroguaiaretic acid (NDGA)) produce a similar inhibitory effect on LPL activity in cultured 3T3-L1 mouse adipocytes. Additionally the LOX inhibitors had no effect on, or inhibited, lipolysis in this cell system (measured as glycerol release). Growing mice fed diet containing 0.1% NDGA for 4 weeks displayed 21% reduction in body fat, which was similar to 23% reduction in body fat produced by feeding diet containing a suboptimal amount of CLA (0.1%) for 4 weeks. Feeding diet containing both 0.1% NDGA and 0.1% CLA resulted in 51% reduction in body fat which was accompanied by significant increases in whole body water and protein. Aspirin, an inhibitor of cyclooxygenase 1 and 2, had no effect on LPL activity in 3T3-L1 adipocytes, did not affect body composition when fed to growing mice, and failed to influence the effects of CLA on LPL activity in 3T3-L1 cells or body composition in mice. These findings appear to provide new perspectives and insights into the relationships between CLA, eicosanoids, the control of lipid accumulation in adipocytes, and effects of CLA on the immune system. 相似文献
7.
Min-Hyeok Kang Su-Hong Choi Jae-Seop Oh 《Journal of electromyography and kinesiology》2013,23(4):787-793
We examined the influence of the application of postural taping on the kinematics of the lumbo–pelvic–hip complex, electromyographic (EMG) activity of back extensor muscles, and the rating of perceived exertion (RPE) in the low back during patient transfer. In total, 19 male physical therapists with chronic low back pain performed patient transfers with and without the application of postural taping on the low back. The kinematics of the lumbo–pelvic–hip complex and EMG activity of the erector spinae were recorded using a synchronized 3-D motion capture system and surface EMG. RPE was measured using Borg’s CR-10 scale. Differences in kinematic data, EMG activity, and RPE between the two conditions were analyzed using a paired t-test. Peak angle and range of motion (ROM) of lumbar flexion, EMG activity of the erector spinae, and RPE decreased significantly, while peak angle and ROM of pelvic anterior tilt and hip flexion increased significantly during patient transfer under the postural taping condition versus no taping (p < 0.05). These findings suggest that postural taping can change back extensor muscle activity and RPE as well as the kinematics of the lumbo–pelvic–hip complex in physical therapists with chronic low back pain during patient transfer. 相似文献
8.
Ignacio Islas Víctor M. Loyola-Vargas María de Lourdes Miranda-Ham 《In vitro cellular & developmental biology. Plant》1994,30(1):81-83
Summary Tryptophan decarboxylase (TDC), the enzyme that catalyzes the decarboxylation of tryptophan to trytamine, was studied in aCatharanthus roseus transformed root culture. Its activity was evaluated through the culture cycle (36 days), along with the variations in the
tryptamine pool as well as the accumulation of alkaloids. Ajmalicine and catharanthine contents in the tissues increased coordinately
with an increase in TDC-specific activity after 18 days of growth. No dramatic shifts were observed for the total alkaloid
and tryptamine profiles. 相似文献