Seasonal changes of heart weight and erythrocytes in the Djungarian hamster, Phodopus sungorus

Biology and Diseases of Hamsters

“…Increased food hoarding has been observed in P. sungorus as a behavioral adaptation to provide accessible energy during pregnancy (Bartness, 1997). Seasonal acclimation of blood-gas transport during periods of colder temperatures is facilitated by an increased relative heart weight, increased surface area of erythrocytes, and slightly altered hemoglobin content, all of which aid in oxygen transport (Puchalski and Heldmaier, 1986). This implies that the two species of Djungarian hamsters have undergone evolutionary selection pressures with respect to reproductive endocrinology (Mcmillan and Wynne-Edwards, 1998).…”

Biology and Diseases of Hamsters

“…Increased food hoarding has been observed in P. sungorus as a behavioral adaptation to provide accessible energy during pregnancy (Bartness, 1997). Seasonal acclimation of blood-gas transport during periods of colder temperatures is facilitated by an increased relative heart weight, increased surface area of erythrocytes, and slightly altered hemoglobin content, all of which aid in oxygen transport (Puchalski and Heldmaier, 1986). This implies that the two species of Djungarian hamsters have undergone evolutionary selection pressures with respect to reproductive endocrinology (Mcmillan and Wynne-Edwards, 1998).…”

Seasonal variations in hematological values and heart weight in two small mammals, a mouse: Apodemus sylvaticus, and a vole: Pitymys duodecimcostatus

“…Kostelecka-Myrcha (1967) found greater relative heart weights in those C. glareolus that lived at high altitudes, and interpreted this as an adaptation mechanism to increase the oxygen demands at low 0 2 pressure since no differences were observed in the hematological values. Sealander (1966), in C. rutilus, andHeroux (1961), and Puchalski and Heldmaier (1986), in hamster, noted an increase in relative heart weight during the cold months, which might be indicative of a seasonal change. The physiological impact of an increase in heart weight is obvious, since improved circulatory efficiency is obtained by an increase in cardiac output per unit of body weight.…”

“…He explained this as being a result of the uniform habitat temperature. Recently, Puchalski and Heldmaier (1986) studied seasonal hematological variations in hamster. They created two experimental groups, one exposed to seasonal and temperature variations and the other had thermoneutral conditions.…”

“…Other factors, such as photoperiod (Puchalski and Heldmaier 1986), acclimatization to cold (Heroux 1961, Malzahn 1974, Sealander 1966, or altitude (Kostelecka-Myrcha 1967) have also been described as influencing relative heart weight.…”

Biology and Diseases of Hamsters

“…Increased food hoarding has been observed in P. sungorus as a behavioral adaptation to provide accessible energy during pregnancy (Bartness, 1997). Seasonal acclimation of blood-gas transport during periods of colder temperatures is facilitated by an increased relative heart weight, increased surface area of erythrocytes, and slightly altered hemoglobin content, all of which aid in oxygen transport (Puchalski and Heldmaier, 1986). This implies that the two species of Djungarian hamsters have undergone evolutionary selection pressures with respect to reproductive endocrinology (Mcmillan and Wynne-Edwards, 1998).…”

Seasonal variations in hematological values and heart weight in two small mammals, a mouse: Apodemus sylvaticus, and a vole: Pitymys duodecimcostatus

“…Kostelecka-Myrcha (1967) found greater relative heart weights in those C. glareolus that lived at high altitudes, and interpreted this as an adaptation mechanism to increase the oxygen demands at low 0 2 pressure since no differences were observed in the hematological values. Sealander (1966), in C. rutilus, andHeroux (1961), and Puchalski and Heldmaier (1986), in hamster, noted an increase in relative heart weight during the cold months, which might be indicative of a seasonal change. The physiological impact of an increase in heart weight is obvious, since improved circulatory efficiency is obtained by an increase in cardiac output per unit of body weight.…”

“…He explained this as being a result of the uniform habitat temperature. Recently, Puchalski and Heldmaier (1986) studied seasonal hematological variations in hamster. They created two experimental groups, one exposed to seasonal and temperature variations and the other had thermoneutral conditions.…”

“…Other factors, such as photoperiod (Puchalski and Heldmaier 1986), acclimatization to cold (Heroux 1961, Malzahn 1974, Sealander 1966, or altitude (Kostelecka-Myrcha 1967) have also been described as influencing relative heart weight.…”

Biology and Diseases of Hamsters

“…Increased food hoarding has been observed in P. sungorus as a behavioral adaptation to provide accessible energy during pregnancy (Bartness, 1997). Seasonal acclimation of blood-gas transport during periods of colder temperatures is facilitated by an increased relative heart weight, increased surface area of erythrocytes, and slightly altered hemoglobin content, all of which aid in oxygen transport (Puchalski and Heldmaier, 1986). This implies that the two species of Djungarian hamsters have undergone evolutionary selection pressures with respect to reproductive endocrinology (Mcmillan and Wynne-Edwards, 1998).…”

Seasonal variations in hematological values and heart weight in two small mammals, a mouse: Apodemus sylvaticus, and a vole: Pitymys duodecimcostatus

“…Kostelecka-Myrcha (1967) found greater relative heart weights in those C. glareolus that lived at high altitudes, and interpreted this as an adaptation mechanism to increase the oxygen demands at low 0 2 pressure since no differences were observed in the hematological values. Sealander (1966), in C. rutilus, andHeroux (1961), and Puchalski and Heldmaier (1986), in hamster, noted an increase in relative heart weight during the cold months, which might be indicative of a seasonal change. The physiological impact of an increase in heart weight is obvious, since improved circulatory efficiency is obtained by an increase in cardiac output per unit of body weight.…”

“…He explained this as being a result of the uniform habitat temperature. Recently, Puchalski and Heldmaier (1986) studied seasonal hematological variations in hamster. They created two experimental groups, one exposed to seasonal and temperature variations and the other had thermoneutral conditions.…”

“…Other factors, such as photoperiod (Puchalski and Heldmaier 1986), acclimatization to cold (Heroux 1961, Malzahn 1974, Sealander 1966, or altitude (Kostelecka-Myrcha 1967) have also been described as influencing relative heart weight.…”