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J. PRESL, S. RÖHLING, J. HORSKÝ, J. HERZMANN, Changes in Uptake of 3H-estradiol by the Female Rat Brain and Pituitary from Birth to Sexual Maturity, Endocrinology, Volume 86, Issue 4, 1 April 1970, Pages 899–902, https://doi.org/10.1210/endo-86-4-899
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3H-estradiol uptake by various parts of the brain, pituitary, uterus and striated muscle was compared in 5-, 10-, 15-, 20-, 25-, 30-and 50-day-old female rats 2 hr after a single intraperitoneal injection of 40 μCi/100 g body weight. High uptake values at 5 and 10 days are common to all tissues investigated. A sharp decrease in incorporation was observed from the 5th and/or 10th day after birth. Further values are already relatively stable and low, except for the pituitary and uterus. The ratio of the concentration of the radioactivity between the tissues and the cerebral cortex increased significantly in the median eminence at the age of 15 days, in the anterior hypothalamus at the age of 20 days. In the pituitary the ratio tissue/cortex was already significantly higher at 5 days. The high level of brain radioactivity in the youngest animals is very likely a manifestation of high plasma concentrations of tritiated estradiol. The sharp decrease in uptake of radioactivity by the brain after the 10th day, coinciding with termination of the critical post-natal period of neuronal competence, most likely reflects the decrease in level of plasma radioactivity as shown indirectly by the concomitant decrease in radioactive estrogen uptake by the skeletal muscle. The increase in tissue/cortex ratio in the median eminence and anterior hypothalamus suggests the first appearance of specific binding capacity by which the hormone could realize the feedback. (Endocrinology86: 899, 1970)
