Related Experiment Video
Updated: Jul 31, 2026
09:36
Changes in Mammary Gland Morphology and Breast Cancer Risk in Rats
Published on: October 17, 2010
Effects of hypergravity on mammary metabolic function: gravity acts as a continuum
Journal of Applied Physiology (Bethesda, Md. : 1985)
|August 19, 2003
Summary
Spaceflight alters mammary gland metabolism. Increased gravity reduced metabolic activity during pregnancy, but this effect vanished postpartum, showing gravity
Area of Science:
- Space biology
- Gravitational biology
- Mammalian physiology
Background:
- Spaceflight significantly increases mammary metabolic activity in pregnant rats.
- The influence of gravity load on these metabolic changes remains unclear.
Purpose of the Study:
- To investigate the relationship between gravitational load and mammary metabolic activity.
- To determine if hypergravity affects mammary metabolism similarly to microgravity.
Main Methods:
- Pregnant rats were exposed to hypergravity (1.5, 1.75, or 2.0 x gravity) or 1 G during gestation days 11-20.
- Mammary metabolic activity (glucose oxidation and lipid incorporation) was measured on gestation day 20 and postpartum day 22.
- Data were analyzed for correlations with gravitational load and compared with previous microgravity findings.
Main Results:
- Mammary metabolic rate showed a strong negative correlation with increased gravitational load during gestation.
- Gravitational load accounted for approximately 98% of variation in glucose oxidation and 94% in lipid incorporation.
- Metabolic differences observed during gestation disappeared in the postpartum period.
Conclusions:
- Gravitational load significantly influences mammary tissue metabolism during pregnancy.
- A continuum of response exists across microgravity and hypergravity environments regarding mammary metabolic rate.
- Gravity's effect on mammary metabolism is transient and specific to the gestational period.
Related Concept Videos
01:40Hormonal Regulation
Hormones regulate a significant portion of digestion through activation of the neuroendocrine system. The neuroendocrine system of digestion contains many different hormones all with multiple functions that are both, directly and indirectly, involved in digestion.
01:19Mass and Weight
Mass and weight are often used interchangeably in everyday conversation. For example, medical records often show our weight in kilograms, but never in the correct units of newtons. In physics, however, there is an important distinction. Weight is the pull of the Earth on an object. It depends on the distance from the center of the Earth. Weight dramatically varies if we leave the Earth's surface, unlike mass, which does not vary with location. On the Moon, for example, the acceleration due to...
01:01Weightlessness
When an object is dropped, it accelerates toward the center of the Earth. If the net external force on the object is its weight, it is said to be in free fall; that is, the only force acting on the object is gravity. Galileo was instrumental in showing that, in the absence of air resistance, all objects fall with the same acceleration g. However, when objects on the Earth fall downward, they are never truly in free fall, because there is always some upward resistance force from the air acting...
01:21Acceleration due to Gravity on Earth
According to Newton's law of gravitation, the gravitational force on a body is proportional to its mass. According to Newton's second law of motion, the acceleration produced by an external force is inversely proportional to the force. Hence, the acceleration of an object under an external force of gravitation is independent of its mass.
The acceleration of an object close to the Earth, because of the Earth's gravitational pull, is called the acceleration due to gravity. It is always directed...
The acceleration of an object close to the Earth, because of the Earth's gravitational pull, is called the acceleration due to gravity. It is always directed...
01:20Variation in Acceleration due to Gravity near the Earth's Surface
An object's apparent weight is its weight measured by a spring balance at its location. It is different from its true weight, the force with which the Earth pulls it, because of the Earth's rotation. Mathematically, an object's apparent weight equals its true weight minus the centripetal force that keeps it in a circular motion along with the Earth's surface every 24 hours.
The difference between the true and apparent weights is proportional to the square of the Earth's angular speed. Since the...
The difference between the true and apparent weights is proportional to the square of the Earth's angular speed. Since the...
01:12The Mammary Glands
The female breast is a hemispheric projection of variable size positioned anterior to the pectoralis major and serratus anterior muscles. A fascia layer composed of dense, irregular connective tissue connects it to these muscles.
Each breast features a pigmented projection known as the nipple, through which milk emerges via closely spaced openings of ducts, referred to as lactiferous ducts. Surrounding the nipple is a circular pigmented area of skin named the areola, which appears rough due to...
Each breast features a pigmented projection known as the nipple, through which milk emerges via closely spaced openings of ducts, referred to as lactiferous ducts. Surrounding the nipple is a circular pigmented area of skin named the areola, which appears rough due to...