Life Lines by Dr. Dolittle

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Tag Archive for ‘American Journal of Physiology’

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Role of phoenixin-20 in regulating appetite and glucose metabolism

Phoenixin-20 is a small peptide that has been detected in mammals, birds, amphibians and fish. Studies have shown that it can modify reproductive processes in female mammals and fish. In addition, it has been shown in mammalian studies to act as a pain reducer and modulator of food intake. In a new study published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology, researchers explored whether phoenixin-20 has […]

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The key to the fountain of youth?

I just read an interesting article on the physiology of long-lived species that was published in Physiology. Some animals seem to have discovered the secret to the fountain of youth. Take the long-lived naked mole rat (Heterocephalus glaber) for example. These animals are able to maintain juvenile traits across their lifespan by growing slowly, having low levels of hormones responsible for development and delaying the onset of sexual maturity. Dwarf […]

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Developing Pacific molluscs produce their own carbohydrates

Animals that develop within an egg, must rely on the egg yolk for nutrition for healthy development. While we have known that proteins and fats in the egg are important for development, the role of carbohydrates in the development of molluscs is a bit vague. A new study published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology examined the role of carbohydrates in the development of Pacific […]

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Why pigs and people absorb more sugar from their diet than fish

Researchers at the University of Saskatchewan in Canada compared how pigs and fish absorb glucose (i.e. sugar) from the diet. They did this by measuring how well glucose moves across the intestinal wall. Their findings appear in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology.  Transport of dietary glucose from the gut to the blood is facilitated by glucose transporters that pick up glucose and move it […]

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Researchers explore how the largest animals get enough to eat

Ever wonder how baleen whales (Mysticeta) get enough to eat? The mechanism is described for rorqual whales (Balaenopteridae) in a review article published this past October in Physiology. Researchers have found that rorqual whales (ex: blue whales and fin whales), in particular, have an interesting strategy for foraging. The process includes 5 steps that take place in rapid succession (about 20-90 sec total): quick forward lunges toward prey; opening their […]

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Low-calorie sweeteners – harmful or hype?

Researchers at Columbia University wanted to examine whether low-calorie sweeteners disrupt glucose tolerance as there are conflicting reports in both human and animal studies. Their results examining the link between low-calorie sweeteners and glucose regulation in mice are published in the upcoming issue of the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology. In their first experiment, the research team found no differences in glucose tolerance or body […]

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Importance of feeding chicks shortly after hatching

While egg yolks are rich in lipids, chicks consume mainly carbohydrates after hatching. This ability to switch between using nutrients provided by the mother in the egg and those the chick must acquire from the environment is important for the normal growth and metabolism of the birds after hatching. Delayed access to foods after hatching can therefore have long term effects on the animals. Transport of animals from hatcheries to […]

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How some fish may compensate for low environmental oxygen

     Adult fish rely on gills to extract oxygen from the surrounding water. Larval fish, on the other hand, do not have well-developed gills and instead rely primarily on gas exchange across their skin.      In a new study published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology, researchers examined whether larval fish could use their pectoral fins to increase the flow of water […]

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Researchers explore why fetuses that experienced intrauterine growth restriction have smaller muscles

We have talked several times about the long-lasting issues related to growth restriction of a fetus during pregnancy: Intrauterine growth restriction increases risk of cardiovascular disease as adults Intrauterine growth restriction increases risk of insulin resistance as adults It can also result in offspring that have smaller muscles. New research published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology suggests this may be due to adaptations to […]

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Warm hypoxic waters impair heart function in some fish

Events causing bodies of water to become hypoxic (low oxygen levels) are increasing with climate change. Water can become hypoxic when it warms up or there are changes in tidal flow, density, wind patterns as well as separation from the main source, such as occurs in a tidepool. While some fish are tolerant of hypoxia and even anoxia (oxygen depleted) environments others, such as Atlantic cod and steelhead trout, rely […]

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