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Biomedical subjects

S Schapiro

Publications and source records attributed to S Schapiro.

27 records · Page 2Linked to original sources
PubMed1967

Thyroxine: effects of neonatal administration on maturation, development, and behavior.

Thyroxine was administered to infant rats within the first 3 days of postnatal life; controls receiving 0.01N NaOH were from the same litter. Thyroxine accelerated the maturation of the pituitary-adrenal response to elec tric shock. The "startle response" ap peared earlier in the experimental ani mals, as did the development and re sponse of the electroencephalogram to novel stimuli. The thyroxine-treated rats, when 16 to 18 days old, acquired a conditioned-avoidance response faster than did controls.

Adrenal Glands↗
PubMed1966

Maturation of a stress-activated mechanism inhibiting induction of tyrosine transaminase.

Rats of various ages were subjected to the stress of 30 minutes on a noisy reciprocating shaker 4 hours before their liver tyrosine transaminase and tryptophan pyrrolase activities were measured. Adrenalectomized infants and adults and hypophysectomized adults were also stressed. Intact, stressed infants exhibited an increase in tyrosine transaminase activity, while intact, stressed adults showed no change. In the stressed adrenalectomized adult, tyrosine transaminase activity markedly decreased, while adrenalectomized infants showed no change. Hypophysectomy largely, but not completely, abolished inhibition in the adults. Tryptophan pyrrolase activity, when present, was increased by stress in all age groups, but the increase was abolished by adrenalectomy and hypophysectomy. The results suggest stress-activation of a pituitary mechanism that inhibits or represses activation of tyrosine transaminase and that may not function during early postnatal life.

Adrenalectomy↗