Life Lines by Dr. Dolittle

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Tag Archive for ‘American Journal of Physiology’

Rapid switches in metabolism of hibernating animals

  In a new study published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology, researchers examined how changes in metabolism during torpor are regulated in 13-lined ground squirrels (Ictidomys tridecemlineatus). During hibernation, these animals cycle between bouts of torpor (about 2 weeks each) when their metabolism is reduced by 95% and body temperature can drop to 5degC and short states of interbout euthermia when both temperature […]

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Editor’s picks for 2018

The Editor’s Picks for 2018 have been released for the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology. According to the editorial team, the focus of this journal is on “the regulation of whole organismal function that requires the interplay of multiple organ and tissue systems.” The top comparative physiology articles of 2018 included: An article by Hersh et al., who provided evidence that little skates may be useful […]

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Birds have a unique way of preventing muscle wasting

Muscle wasting is a major complication associated with cirrhosis and liver failure. Normally the liver functions to convert ammonia into urea. But with liver failure, this process does not work well leading to high levels of circulating ammonia, which is thought to contribute to muscle wasting in mammals. A new study published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology, explored whether birds have the same muscle wasting […]

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Dealing with the cold

Cold-tolerant insects have developed several strategies for dealing with cold temperatures. A new study published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology explored how spotted wing drosophila (Drosophila suzukii), in particular, adapted physiologically to cold exposure. They discovered that animals adapted to living in the cold had altered the structure of their cellular membranes in ways that kept the membrane fluid and prevented it from becoming rigid. Moreover, […]

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Rising water temperatures masculinizes Nile tilapia

Nile tilapia, Oreochromis niloticus, is a species of freshwater fish native to Egypt and Africa. Global warming has the potential to significantly impact this species as water temperatures above 32 to 36.5 degrees Celsius can induce young fish (10-30 days after fertilization) that are genotypically female to become masculinized. Moreover, a recent study published in PLOS ONE showed that some young fish choose to visit warmer waters. A new study published […]

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Blood flow shifts during diving

In many mammals exposure to hypoxic conditions results in the release of a vasodilator called nitric oxide, which improves blood flow and protects oxygen delivery to tissues throughout the body. Diving animals appear to be unique in that some of their blood vessels stay constricted while they are diving even though they experience hypoxia. A new study published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology explored […]

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Growth restriction in utero increases risk for developing insulin resistance

  A new study published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology, explored how restricted growth of a fetus during pregnancy can lead to insulin resistance later in life. They studied this risk factor in guinea pigs as larger litter sizes are known to restrict the growth of developing fetuses. Findings from the study showed that neonatal guinea pigs grow rapidly after birth to compensate for […]

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Lactate directly increases breathing

Hypoxic environments increase ventilation in animals. This helps to bring in more oxygen when environmental levels may be limited. With limited oxygen availability, the body turns to anaerobic metabolism, resulting in the production of lactate ions. These ions are known to indirectly stimulate breathing by lowering blood pH and were more recently discovered to directly stimulate the carotid body to increase breathing. For this reason, lactate ions are thought to […]

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PUFAs change muscle characteristics in a migratory bird without improving flight performance

Migratory birds are undoubtedly endurance athletes. In fact, their flights last hours to days. Could you imagine? But, unlike mammals that fuel endurance exercise by burning carbohydrates, birds fuel their endurance flights with fat. In a new study published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology, researchers were curious about whether the TYPE of dietary fat used to fuel endurance exercise was important. To examine this […]

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Historical perspectives on homeostasis

In a new article published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology, Dr. David S. Goldstein (National Institutes of Health) presents an elegant historical perspective on homeostasis. Walter B. Cannon (1871-1945) was a physiologist at Harvard Medical School who is credited with coining the term “homeostasis” to describe how the body attempts to regulate itself to stay healthy. The ability for the body to regulate the […]

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