Abstract
In male and female prepubertal rats, E1 and E2 measured by radio-immunoassay using an E2-17 antibody show a peak (E1=3.8±1.4 ng/ml and E2=0.4±0.2 ng/ml) in 13–15 days old animals. P levels which are low at that age (≤ 1 ng/ml) increase after 21 days, Adrenal-ectomy and/or castration experiments support the conclusion that E1 and E2 have mainly an adrenal origin. A relationship has been found between plasma and adrenal concentrations for E1 and P but not for E2. Measurements by double isotope dilution method show that most of “E1” and “E2” are not true E1 and E2. Similar results are given with E1-6 and E2-6 antibodies. The affinity of “E1” compared to E1 is higher for α-fetoprotein than for the anti-E2-17 antibody, whereas the affinity of “E2” compared to E2 is higher for the anti-E2-17 antibody and the uterine cytosol than for α-fetoprotein. The steroidgenesis inhibitors, cycloheximide and aminoglutethimide, significantly lower plasma and adrenal “E1” and “E2” levels; dexamethasone is also effective. ACTH-Immediat does not produce significant variations of “E2” and “E2” although P is augmented. A 2–3 days administration of ACTH-Retard produces a dramatic fall in plasma and adrenal “E1” and “E2” concentrations. A possible physiological role for these compounds is suggested by their ability to displace (3H)-E2 from its uterus cytosol receptor.
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Audi, L., Morera, A. & Saez, J. PROGESTERONE (P), ESTRONE (E1 AND ESTRADIOL (E2) BEFORE PUBERTY IN THE RAT : ORIGIN AND EVOLUTION. Pediatr Res 9, 667 (1975). https://doi.org/10.1203/00006450-197508000-00014
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DOI: https://doi.org/10.1203/00006450-197508000-00014