An androgen receptor has been identified in the cytosolic and nuclear extracts of the Harderian gland of the frog, Rana esculenta. A single class of high-affinity binding sites was found: K(d) = 1.9 ± 1.3 (S.D.) nmol/l (n = 26) for the cytosolic extract and K(d) = 0.9 ± 0.8 nmol/l (n = 15) for the nuclear extract. The presence of binding activity in both nuclear and cytosolic extracts and the low rate of ligand-receptor dissociation are characteristics that distinguish this receptor from a steroid-binding protein. The K(d) did not show any sex difference and did not exhibit any secretory activity-related change. Binding in both cytosolic and nuclear extracts was specific for androgens (testosterone = 5α-dihydrotestosterone); oestradiol-17β showed a 30% cross-reaction; moreover, specific binding of [3H]oestradiol-17β was not detectable. The binding capacity of the Harderian gland increased progressively in both fractions from October to December, reaching a peak in May, and decreased suddenly during July to August. The lack of any morphological sex-related difference in the Harderian gland of the green frog might be accounted for by the high amount of circulating androgens as well as a similar concentration of androgen receptor in both sexes.
Androgen receptor in the Harderian gland of Rana esculenta
D'ISTRIA M;CHIEFFI-BACCARI Gabriella;DI MATTEO L;MINUCCI S;VARRIALE B;
1991
Abstract
An androgen receptor has been identified in the cytosolic and nuclear extracts of the Harderian gland of the frog, Rana esculenta. A single class of high-affinity binding sites was found: K(d) = 1.9 ± 1.3 (S.D.) nmol/l (n = 26) for the cytosolic extract and K(d) = 0.9 ± 0.8 nmol/l (n = 15) for the nuclear extract. The presence of binding activity in both nuclear and cytosolic extracts and the low rate of ligand-receptor dissociation are characteristics that distinguish this receptor from a steroid-binding protein. The K(d) did not show any sex difference and did not exhibit any secretory activity-related change. Binding in both cytosolic and nuclear extracts was specific for androgens (testosterone = 5α-dihydrotestosterone); oestradiol-17β showed a 30% cross-reaction; moreover, specific binding of [3H]oestradiol-17β was not detectable. The binding capacity of the Harderian gland increased progressively in both fractions from October to December, reaching a peak in May, and decreased suddenly during July to August. The lack of any morphological sex-related difference in the Harderian gland of the green frog might be accounted for by the high amount of circulating androgens as well as a similar concentration of androgen receptor in both sexes.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
