Activities of oxidative and glycolytic enzymes in fetal heart, lung, and brain in the Weddell seal

1981 ◽  
Vol 59 (6) ◽  
pp. 1172-1175
Author(s):  
B. J. Murphy ◽  
P. W. Hochachka
Keyword(s):  
Fetal Heart ◽  
Weddell Seal ◽  
Glycolytic Enzymes ◽  
Metabolic Responses ◽  
Marker Enzymes ◽  
Mitochondrial Marker ◽  
Adult Type ◽  
Metabolic Functions ◽  
Oxidative And Glycolytic Enzymes ◽  
Near Term

The oxidative and glycolytic capacities of brain, heart, and lung in near-term Weddell seal fetuses were estimated from the maximal activities of four mitochondrial marker enzymes and four glycolytic enzymes. The catalyic potentials for both groups of enzymes were similar to adult levels in all three organs examined. It was concluded that the critical metabolic functions performed by these three central organs during diving are already fully developed in the fetal seal. This early development of adult-type metabolic machinery did not appear to be a preparatory step for later extrauterine function, but rather appeared to be necessary for times of normal maternal diving, when fetal metabolic responses mimic those of the mother.

Fetal cardiovascular and metabolic responses to simulated diving in the Weddell seal

1980 ◽  
Vol 49 (3) ◽  
pp. 424-430 ◽  
Author(s):  
G. C. Liggins ◽  
J. Qvist ◽  
P. W. Hochachka ◽  
B. J. Murphy ◽  
R. K. Creasy ◽  
...  
Keyword(s):  
Heart Rate ◽  
Fetal Heart ◽  
Control Period ◽  
Weddell Seal ◽  
Blood Gas ◽  
Weddell Seals ◽  
Control Value ◽  
O2 Transport ◽  
Arterial Ph ◽  
Near Term

Fetal responses to normobaric diving simulated by submersion of the maternal head for 20 min were studied in four conscious Weddell seals near term. Microspheres injected into the maternal aorta were distributed to the placenta and kidneys in the ratio of 0.4 in the control period and 19.3 during diving, suggesting minimal placental vasoconstriction. Fetal heart rate fell during diving from a mean control value of 90 to 34 beats/min after 4 min. The onset of fetal bradycardia was not consistently associated with changes in blood gas tensions. Diving was associated with a fall in fetal arterial O2 tension from 24 to 9 Torr, arterial CO2 tension rose from 47 to 85 Torr, and arterial pH fell from 7.35 to 7.24. Fetal-maternal gradients for CO2 and H+ transport remained constant, whereas the gradient for O2 transport fell from 47 Torr before diving to 14 Torr at the end of diving. Blood lactate concentrations increased three- to fourfold during diving and reached peak values 10-15 min after diving ended. The similarity of the fetal and maternal heart rate responses to diving is consistent with the presence of physiological oxygen-conserving reflexes akin to the adult's.

Ontogeny of some enzymes of glycogen metabolism in rabbit fetal heart, lungs, and liver

1983 ◽  
Vol 61 (4) ◽  
pp. 191-197 ◽  
Author(s):  
Bhagu R. Bhavnani
Keyword(s):  
Glycogen Phosphorylase ◽  
Fetal Heart ◽  
Glycogen Synthase ◽  
Fetal Liver ◽  
Active Form ◽  
Fetal Lung ◽  
Glycogen Metabolism ◽  
Near Term ◽  
Surfactant Phospholipids ◽  
Total Tissue

Optimum conditions were established for the assay of glycogen, glycogen synthase, glycogen phosphorylase, phosphoglucomutase, and glucose-6-phosphatase in rabbit fetal heart, lung, and liver. Using these methods, the pattern of appearance of glycogen and the above four enzymes was established from day 18 of gestation to day 8 after birth. The results indicate that total tissue glycogen reaches maximum levels between days 22 and 24 in the heart, days 24 and 26 in the lung, and days 30 and 31 in the liver. In all three tissues, the rapid rise or depletion of glycogen is coincident with a corresponding increase in glycogen synthase and glycogen phosphorylase activities. However, substantial amounts of glycogen synthase are present both prior to and after the accumulation of glycogen. Similarly, considerable amounts of glycogen phosphorylase are present early in gestation, yet deposition of glycogen occurs. Both the I and D forms of glycogen synthase are present in the three tissues, the major being the physiologically inactive D form. Similarly both the a and b forms of glycogen phosphorylase are present, with the a form (active form) making up about 30–60% of the total phosphorylase activity. Glucose-6-phosphatase was absent in fetal heart and lung throughout the period of gestation investigated. Low levels of this enzyme were detectable in fetal liver near term. The phosphoglucomutase activity increased progressively from day 22 of gestation in all three tissues and continues to increase after birth. The disappearance of fetal lung glycogen occurs between days 27 and 28 at a time when surfactant phospholipids first appear. These findings indicate that the breakdown of glycogen is providing the fetal lung cells with energy necessary for surfactant phospholipid biosynthesis.

Metabolic Responses to Thermal Stressors of Altitude-Acclimated Rats

1958 ◽  
Vol 195 (3) ◽  
pp. 739-743 ◽  
Author(s):  
Henry B. Hale ◽  
Roy B. Mefferd
Keyword(s):  
Urine Volume ◽  
Temperature Response ◽  
Ground Level ◽  
Metabolic Responses ◽  
Control Group ◽  
Response Curves ◽  
Level Pressure ◽  
Metabolic Functions ◽  
Per Se ◽  
The Difference

Fasting 24-hour exposures of altitude-acclimated rats (380 mm Hg, 18,000 ft. simulated) to ground level pressure (750 mm Hg) at either cold (3°C), neutral (24°C), or hot (35°C) temperatures seldom resulted in return of their metabolic functions to preacclimative ‘normalcy.’ Although the control and altitude-acclimated groups both were accustomed to neutral temperatures (24° and 26°C), quantitative differences at ground level and altitude occurred in various indices of water, mineral and nitrogen metabolism. Of the 32 physiologic variables studied, only 4 (ratio of urine volume/ water intake, and urinary excretion of potassium, creatinine and glycine) failed to differentiate the responses of the altitude- and ground-accustomed rats. The temperature response curves of the altitude group tended to parallel the corresponding ones for the control group, but most variables were on higher or lower planes. The difference in plane resulted either from the effects of the return to ground level pressure, or from nonreversible effects of acclimation to altitude per se.

scholarly journals The subcellular loclization and properties of the ferrochelatase of etiolated barley

1976 ◽  
Vol 156 (2) ◽  
pp. 309-314 ◽  
Author(s):  
H N Little ◽  
O T G Jones
Keyword(s):  
Density Gradient ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Mitochondrial Fraction ◽  
Marker Enzymes ◽  
Mitochondrial Marker

The etioplast fraction prepared from dark-grown barley contained the enzyme ferrochelatase. A mitochondrial fraction prepared from the same dark-grown tissue also contained ferrochelatase. After density-gradient centrifugation an etioplast band was collected that was free from detectable mitochondrial marker enzymes and yet retained ferrochelatase activity. A membrane band that was enriched in mitochondria also contained ferrochelatase. The ferrochelatase in these two bands had different pH optima, but appeared very similar in their porphyrin specificity and their inhibition by metalloporphyrins.

The skin and hair of the southern elephant seal, (Mirounga Leonina (L.) II. pre-natal and early post-natal development and moulting

1967 ◽  
Vol 15 (2) ◽  
pp. 349 ◽  
Author(s):  
JK Ling ◽  
CDB Thomas
Keyword(s):  
Cellular Proliferation ◽  
Elephant Seal ◽  
Hair Follicles ◽  
Southern Elephant Seal ◽  
Mirounga Leonina ◽  
Adult Type ◽  
Root Sheath ◽  
Stratum Lucidum ◽  
Near Term ◽  
Post Implantation

The embryological development of hair follicles and the emergence and growth of the foetal pelage of the southern elephant seal, Mirounga leonina (L.), are described in terms of 10 recognizable stages. Follicle primordia appear at a post-implantation age of about 8 weeks and growth of the first definitive hairs takes approximately 14 weeks. Sebaceous glands develop after the sweat gland anlagen, but their ontogeny is more rapid and they function earlier in the formation of the hair canals. The latter are formed by epidermal cellular accretion from without and sebaceous cellular activity within the developing pilosebaceous unit. Development of three epidermal layers is also described and the absence of a stratum granulosum and stratum lucidum noted. The formation of muscle, collagen, and elastic fibres, and blood vessels in the dermis has been observed and described. The histological development of the first adult-type hair generation has been followed in near-term foetuses and young pups until the latter go to sea. The post-natal moult usually commences about 1 week after birth and takes 3 weeks for its completion. Whereas the foetal hairs are not connected to the stratum corneum lining the pilary canal, with a result that they are shed individually, the epidermis and all subsequent hair generations are united. This union is established after the post-natal moult at the end of the active follicular phase by a process of epidermal and external root sheath cellular proliferation around the bottom of the hair canal.

Heart rate and body temperature during free diving of Weddell seals

1987 ◽  
Vol 253 (2) ◽  
pp. R344-R351 ◽  
Author(s):  
R. D. Hill ◽  
R. C. Schneider ◽  
G. C. Liggins ◽  
A. H. Schuette ◽  
R. L. Elliott ◽  
...  
Keyword(s):  
Heart Rate ◽  
Body Temperature ◽  
Adult Male ◽  
Fetal Heart Rate ◽  
Fetal Heart ◽  
Weddell Seal ◽  
The Body ◽  
Weddell Seals ◽  
The Mean ◽  
Slow Onset

We have developed and successfully used the first microprocessor-controlled monitors for collection of data on depth, heart rate, and body temperature of one fetal and five adult male freely swimming Weddell seals. Adult seals almost invariably experienced a prompt bradycardia at the start of each dive, and the mean heart rate during diving was significantly lower for dives greater than 20 min (P greater than 0.999). The heart rate was also significantly greater during the ascent portion of dives when compared with the descent portion (P greater than 0.95). The fetal seal experienced a slow onset of bradycardia when its mother dived; during diving the fetal heart rate decreased by an average of 1.1 beats/min for each minute of the dive. The fetal heart rate generally took approximately 10 min to recover to predive levels after its mother resurfaced to breathe. The body temperature of one adult male Weddell seal showed a decrease of greater than 1.5 degrees C from resting levels before dives of greater than 15 min were initiated and a drop of over 2 degrees C before dives of greater than 30 min duration.

Diurnal and other cyclic variations in human fetal heart rate near term

1982 ◽  
Vol 142 (5) ◽  
pp. 535-544 ◽  
Author(s):  
G.H.A. Visser ◽  
J.D.S. Goodman ◽  
D.H. Levine ◽  
G.S. Dawes
Keyword(s):  
Heart Rate ◽  
Fetal Heart Rate ◽  
Fetal Heart ◽  
Human Fetal Heart ◽  
Cyclic Variations ◽  
Near Term
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