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Biomedical subjects

J Roffi

Publications and source records attributed to J Roffi.

At least 55 records · Page 3Linked to original sources
PubMed1978

Pituitary adrenocortical response to stress during the first day of post-natal life in the rat.

During the first hours of post-natal life, the newborn rat does not respond to ether stress by a rapid increase of ACTH secretion. Ether inhalation by 5- and 12-hour-old animals slightly but significantly increases plasma and adrenal corticosterone levels, but only 30 min after the onset of stress. At 1 day of age, adrenal response is established. The adrenal cortex of 5-hour-old animals responds normally to an intraperitoneal injection of 25 mU of ACTH. These results indicate that there is an absolute stress non-response period in newborn rats which is followed by a relative stress non-response period. The lack of response is not due to an organic block of the adrenal cortex, but could be due to the accumulation of elevated levels of corticosterone in the central nervous system.

Adrenal Cortex↗
PubMed1978

Changes in testicular weight and serum gonadotropin and testosterone levels before, during, and after birth in the perinatal rat.

Changes in serum and pituitary LH and FSH concentrations have been measured in the newborn male rat before, during, and up to 24 h after birth. A sudden and transient increase of serum and pituitary gonadotropins is observed at birth, which is followed by a rapid increase of absolute and relative testicular weights between 2--12 h (P less than 0.0001) and by a transient increase of serum testosterone between 0 h in utero (810 +/- 26 pg/ml) and 2 h (2820 +/- 318 pg/ml; P less than 0.0001). Similarly, premature newborn rats obtained by cesarian delivery on day 20 of gestation also exhibited an increase in testicular weight between 0--6 h and an increase in serum testosterone levels between 0 h (730 +/- 170 pg/ml) and 2 h (3400 +/- 300 pg/ml; P less than 0.001) with only a slight increase in serum LH. These results show that the hypophyseo-testicular axis of the rats is stimulated at the moment of birth. The factors responsible for this stimulation are discussed. This transient testicular crisis occurring at birth could affect the process of masculinization of the central nervous system of the rat.

Animals↗
PubMed1977

[Increase in serum testosterone in newborn rats].

The changes in serum testosterone and dihydrotestosterone concentrations have been measured in the newborn Rat, before, during and up to 6 hrs after birth. A sudden and transient increase of serum testosterone has been found between 0 and 2 hrs. At 4 hrs, the value returns to that found in the foetus at the end of gestation.

Animals↗
PubMed1975

Norepinephrine in fetal and neonatal rabbit brain.

In the first hour after parturition, the newborn rabbit brain norepinephrine content is about 37% less than that of the fetus of 30th or 31st day. Later on, within 2 to 4 h, the norepinephrine level returns to the prenatal value and remains unchanged between 8 to 12 h. This transitory fall of the brain norepinephrine seems to be linked to the stress conditions which occur during parturition.

Age Factors↗