Thermoregulation in rodents exposed to high-intensity stationary magnetic fields

Rectal temperatures were recorded in mice and rats during exposure to a stationary 7.55 Tesla (1 T = 10(4) Gauss) homogeneous magnetic field, and to magnetic field gradients ranging from 58.1 - 58.6 T/m. Contrary to observations reported recently by other investigators, no evidence was found for a change in the body temperature of rodents exposed to strong homogeneous or gradient magnetic fields.     

Sensitivity to odours in the embryo of the domestic fowl

Sensitivity to odours in the embryo of the domestic fowl was investigated on the day before hatching. Embryos were tested with four odorants: dichloroethane, cineole, amyl acetate and formic acid. Three odorants (dichloroethane, formic acid and cineole) produced an increase in the heart rate and a rise in the rates of beak-clapping and the first two increased the amount of head-shaking. Odorants had little effect on other types of activity. The response to amyl acetate varied between experiments. Blocking the nostrils with wax abolished the response. Some implications of these results are discussed briefly.     

Thermoregulation characteristics of rats exposed to cold in the early postnatal period

Cold adaptation of adult rats (at 4-5 degrees C for 7 weeks) increased their ability to respond to noradrenaline by the rise of body temperature and heat radiation, led to an almost 2-fold increase in the relative brown fat mass (BFM). Adult rats which experienced "cold imprinting" (from the first to the seventh day after birth, 15 min at 4-5 degrees C) showed a far less increment of the BFM on cold adaptation, no additional rise of body temperature and heat radiation in response to noradrenaline. In cold-imprinted rats, the relative surface of the tail and the body surface heat radiation transfer conefficient were found to be reduced. This attests to stable adaptive changes in physical thermoregulation, directed toward increase in animals' heat insulation.     

Ultimobranchial gland of the domestic fowl

Summary The ultimobranchial gland (UBG) of birds is particularly rich in calcitonin, the hypocalcaemic hypophosphataemic hormone, that is secreted by the C-cells of the mammalian thyroid. The principal cells of the UBG have a striking resemblance with the mammalian C-cells, i.e., they possess small intracytoplasmic dense-core secretory granules, 150–300 nm in diameter. The gland also contains a second, morphologically distinct, endocrine cell type with larger granules, 500–800 nm in diameter. A sensitive immunocytochemical reaction was developed with the use of antibodies against salmon calcitonin. By means of this technique the presence of calcitonin-immunoreactive molecules was demonstrated in both secretory cell types of the UB gland of the chicken. This gland can thus be considered as a homogeneous calcitonin-producing tissue. Whether the secretory products are identical is discussed and differences in the secretory pathways are suggested.