TY - JOUR
T1 - The effects of estradiol upon the thymus of the sexually immature female mouse
AU - Thompson, E. Aubrey
N1 - Funding Information:
Thymocytes are target cells for glucocorticoids, as evidenced by the fact that such steroids cause profound involution of the juvenile thymus. Glucocorticoids have been implicated in the physiological process of thymic involution which occurs as animals mature. However, the fact that involution occurs about the time of puberty hints at the involvement of sex hormones. The existence of a thymic-gonadal endocrine axis was first experimentally demonstrated some 80 years ago by Calzolari who observed thymic hyperplasia in castrated animals [l]. It has subsequently been observed that thymic involution can be induced by gonadotropins [2,3], androgens [4,5], and estrogens [d-lo]. The effects of castration and hormone replacement have also been studied by Comsa[ll J. All of these data reveal that the thymus of castrated animals is infantile in morphology, while administration of estrogens and androgens causes the thymus to assume the adult size and morphology. More recent histological studies reveal that sex steroid-induced involution is accompanied by the depletion of lymphoid cells from the thymus [ 12,131. Decreased mitotic activity is also observed [12] along with In appar- * Supported in part by grant number CA24347 from the National Cancer Institute, NIH, DHEW, USA.
PY - 1981/2
Y1 - 1981/2
N2 - The thymus of the sexually immature female DDS mouse contains about 2.4 × 1010 estradiol binding sites/thymus which bind with an apparent dissociation constant of about 2.3 × 10-10M. Estrogen binding sites in the glucocorticoid-involuted thymus are similar in number and binding affinity. The putative estrogen receptor sediments on sucrose density gradients with a velocity of about 8S and binding of estradiol can be completely blocked by the addition of a 100 fold molar excess of diethylstilbestrol. Estrogen receptor levels in male mice were about 1 × 109 sites/thymus. Estrogen binding properties were investigated in thymuses of 11 inbred strains of mice, including 6 strains with a high incidence of lymphoma. The number of estradiol binding sites ranged from 0.6-5.5 × 1010 sites/thymus. The mean number of sites in mice with a high incidence of lymphoma was not significantly different from that observed in strains with low incidence. However, with respect to number of binding sites/thymus, there were two discernable groups of mice. The high line group includes strains DBA/2J, SWR/J, C58/J and SJL/J and has a mean binding value of 4.7 × 1010 sites/thymus. The low line group has a mean binding value of 1.7 × 1010 sites/thymus and includes strains A/J, C57BL/6J, DDS, AKR/J, Balb/c Dub, C3H/FeJ and RF/J. When female DDS mice were injected with 1 μg estradiol or 5 μg testosterone/day for 3 days, no decrease in thymic weight was observed. Estradiol, but not testosterone, caused a 3-4 fold increase in thymic glycerol-3-phosphate dehydrogenase. Thymic glycerol-3-phosphate dehydrogenase in male mice did not increase under the influence of estradiol. Estradiol also stimulated the incorporation of [3H]-uridine into RNA in thymuses of 3 wk old female mice. The incorporation of [3H]-thymidine was inhibited about 40%. No effect upon [3H]-leucine incorporation was observed although estradiol did cause a slight, but significant, decrease in total thymic protein content.
AB - The thymus of the sexually immature female DDS mouse contains about 2.4 × 1010 estradiol binding sites/thymus which bind with an apparent dissociation constant of about 2.3 × 10-10M. Estrogen binding sites in the glucocorticoid-involuted thymus are similar in number and binding affinity. The putative estrogen receptor sediments on sucrose density gradients with a velocity of about 8S and binding of estradiol can be completely blocked by the addition of a 100 fold molar excess of diethylstilbestrol. Estrogen receptor levels in male mice were about 1 × 109 sites/thymus. Estrogen binding properties were investigated in thymuses of 11 inbred strains of mice, including 6 strains with a high incidence of lymphoma. The number of estradiol binding sites ranged from 0.6-5.5 × 1010 sites/thymus. The mean number of sites in mice with a high incidence of lymphoma was not significantly different from that observed in strains with low incidence. However, with respect to number of binding sites/thymus, there were two discernable groups of mice. The high line group includes strains DBA/2J, SWR/J, C58/J and SJL/J and has a mean binding value of 4.7 × 1010 sites/thymus. The low line group has a mean binding value of 1.7 × 1010 sites/thymus and includes strains A/J, C57BL/6J, DDS, AKR/J, Balb/c Dub, C3H/FeJ and RF/J. When female DDS mice were injected with 1 μg estradiol or 5 μg testosterone/day for 3 days, no decrease in thymic weight was observed. Estradiol, but not testosterone, caused a 3-4 fold increase in thymic glycerol-3-phosphate dehydrogenase. Thymic glycerol-3-phosphate dehydrogenase in male mice did not increase under the influence of estradiol. Estradiol also stimulated the incorporation of [3H]-uridine into RNA in thymuses of 3 wk old female mice. The incorporation of [3H]-thymidine was inhibited about 40%. No effect upon [3H]-leucine incorporation was observed although estradiol did cause a slight, but significant, decrease in total thymic protein content.
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U2 - 10.1016/0022-4731(81)90170-9
DO - 10.1016/0022-4731(81)90170-9
M3 - Article
C2 - 6782373
AN - SCOPUS:0019450704
SN - 0022-4731
VL - 14
SP - 167
EP - 174
JO - Journal of Steroid Biochemistry
JF - Journal of Steroid Biochemistry
IS - 2
ER -