Hormonal regulation of an oviducal protein involved in Bufo arenarum fertilization

Characterization and properties of steroid binding protein in Bufo arenarum serum

“…The differences between SBPs' capacities may be largely explained by the fact that Bufo arenarum serum shows a high concentration of endogenous estradiol with a maximum level during the amplexus period of about 20-40 ng/ml (loP7 M), that is approximately 100 times higher than that found in human serum at the time of preovulatory estradiol peak. On the other hand, high levels of circulating testosterone, five times higher than E,, were observed in Bufo arenarum females (Fernandez et al, 1984). These results are in accordance with the 100-fold concentration of Ba SBP with respect to SBP of human, and lend some support to the assumption that throughout the vertebrates, serum sex steroid binding capacities are 10-50 times higher than the circulating sex steroids, and thus are sufficient t o bind most of the circulating hormones.…”

“…Previous results had shown that the biological activity of the PR and the serum concentration of estradiol-17p are closely correlated with the sexual cycle (Fernandez et al, 1984). Concomitantly, we demonstrated that the ultrastructure of oviducal epithelium exhibited seasonal changes according to the ovarian cycle, indicating modulation by steroid hormones (Fernandez et al, 1989a).…”

“…Administration of estradiol-17P (E,), 5 a-dihydrotestosterone (DHT), or testosterone (T), but not progester-0 1994 WILEY-LISS, INC. one (P), induced the proliferation of secretory cells with the development of structures associated with the synthesis of the secretory material into the granules (Fernandez et al, 198913) and the reappearance of biological activity (Fernandez et al, 1984). In accordance with these data we had found that estradiol-17P stimulated the synthesis of PR proteins in either in vivo or in vitro conditions (Mansilla-Whitacre et al, 1992).…”

“…Concomitantly, we demonstrated that the ultrastructure of oviducal epithelium exhibited seasonal changes according to the ovarian cycle, indicating modulation by steroid hormones (Fernandez et al, 1989a). In fact, ovariectomy determined regressive effects in Bufo arenarum PR, inducing cellular involution of the epithelial layer with the disappearance of granules in secretory cells (Fernandez et al, 1989b), in agreement with the diminution of PR activity and estradiol circulating levels (Fernandez et al, 1984).…”

Characterization and properties of steroid binding protein in Bufo arenarum serum

“…The differences between SBPs' capacities may be largely explained by the fact that Bufo arenarum serum shows a high concentration of endogenous estradiol with a maximum level during the amplexus period of about 20-40 ng/ml (loP7 M), that is approximately 100 times higher than that found in human serum at the time of preovulatory estradiol peak. On the other hand, high levels of circulating testosterone, five times higher than E,, were observed in Bufo arenarum females (Fernandez et al, 1984). These results are in accordance with the 100-fold concentration of Ba SBP with respect to SBP of human, and lend some support to the assumption that throughout the vertebrates, serum sex steroid binding capacities are 10-50 times higher than the circulating sex steroids, and thus are sufficient t o bind most of the circulating hormones.…”

“…Previous results had shown that the biological activity of the PR and the serum concentration of estradiol-17p are closely correlated with the sexual cycle (Fernandez et al, 1984). Concomitantly, we demonstrated that the ultrastructure of oviducal epithelium exhibited seasonal changes according to the ovarian cycle, indicating modulation by steroid hormones (Fernandez et al, 1989a).…”

“…Administration of estradiol-17P (E,), 5 a-dihydrotestosterone (DHT), or testosterone (T), but not progester-0 1994 WILEY-LISS, INC. one (P), induced the proliferation of secretory cells with the development of structures associated with the synthesis of the secretory material into the granules (Fernandez et al, 198913) and the reappearance of biological activity (Fernandez et al, 1984). In accordance with these data we had found that estradiol-17P stimulated the synthesis of PR proteins in either in vivo or in vitro conditions (Mansilla-Whitacre et al, 1992).…”

“…Concomitantly, we demonstrated that the ultrastructure of oviducal epithelium exhibited seasonal changes according to the ovarian cycle, indicating modulation by steroid hormones (Fernandez et al, 1989a). In fact, ovariectomy determined regressive effects in Bufo arenarum PR, inducing cellular involution of the epithelial layer with the disappearance of granules in secretory cells (Fernandez et al, 1989b), in agreement with the diminution of PR activity and estradiol circulating levels (Fernandez et al, 1984).…”

Nuclear maturation inducers in Bufo arenarum oocytes

“…Even though progesterone is considered to be the hormone that physiologically triggers meiotic resumption in amphibians (Jalabert et al, 1991), our observations demonstrate that DHT, an androgen with extremely high circulating levels in Bufo arenarum females (Fernández et al, 1984), is also capable of inducing nuclear maturation, its action being dose-and time-dependent.…”

Characterization and properties of steroid binding protein in Bufo arenarum serum

“…The differences between SBPs' capacities may be largely explained by the fact that Bufo arenarum serum shows a high concentration of endogenous estradiol with a maximum level during the amplexus period of about 20-40 ng/ml (loP7 M), that is approximately 100 times higher than that found in human serum at the time of preovulatory estradiol peak. On the other hand, high levels of circulating testosterone, five times higher than E,, were observed in Bufo arenarum females (Fernandez et al, 1984). These results are in accordance with the 100-fold concentration of Ba SBP with respect to SBP of human, and lend some support to the assumption that throughout the vertebrates, serum sex steroid binding capacities are 10-50 times higher than the circulating sex steroids, and thus are sufficient t o bind most of the circulating hormones.…”

“…Previous results had shown that the biological activity of the PR and the serum concentration of estradiol-17p are closely correlated with the sexual cycle (Fernandez et al, 1984). Concomitantly, we demonstrated that the ultrastructure of oviducal epithelium exhibited seasonal changes according to the ovarian cycle, indicating modulation by steroid hormones (Fernandez et al, 1989a).…”

“…Administration of estradiol-17P (E,), 5 a-dihydrotestosterone (DHT), or testosterone (T), but not progester-0 1994 WILEY-LISS, INC. one (P), induced the proliferation of secretory cells with the development of structures associated with the synthesis of the secretory material into the granules (Fernandez et al, 198913) and the reappearance of biological activity (Fernandez et al, 1984). In accordance with these data we had found that estradiol-17P stimulated the synthesis of PR proteins in either in vivo or in vitro conditions (Mansilla-Whitacre et al, 1992).…”

“…Concomitantly, we demonstrated that the ultrastructure of oviducal epithelium exhibited seasonal changes according to the ovarian cycle, indicating modulation by steroid hormones (Fernandez et al, 1989a). In fact, ovariectomy determined regressive effects in Bufo arenarum PR, inducing cellular involution of the epithelial layer with the disappearance of granules in secretory cells (Fernandez et al, 1989b), in agreement with the diminution of PR activity and estradiol circulating levels (Fernandez et al, 1984).…”

Nuclear maturation inducers in Bufo arenarum oocytes

“…Even though progesterone is considered to be the hormone that physiologically triggers meiotic resumption in amphibians (Jalabert et al, 1991), our observations demonstrate that DHT, an androgen with extremely high circulating levels in Bufo arenarum females (Fernández et al, 1984), is also capable of inducing nuclear maturation, its action being dose-and time-dependent.…”

Characterization and properties of steroid binding protein in Bufo arenarum serum

“…The differences between SBPs' capacities may be largely explained by the fact that Bufo arenarum serum shows a high concentration of endogenous estradiol with a maximum level during the amplexus period of about 20-40 ng/ml (loP7 M), that is approximately 100 times higher than that found in human serum at the time of preovulatory estradiol peak. On the other hand, high levels of circulating testosterone, five times higher than E,, were observed in Bufo arenarum females (Fernandez et al, 1984). These results are in accordance with the 100-fold concentration of Ba SBP with respect to SBP of human, and lend some support to the assumption that throughout the vertebrates, serum sex steroid binding capacities are 10-50 times higher than the circulating sex steroids, and thus are sufficient t o bind most of the circulating hormones.…”

“…Previous results had shown that the biological activity of the PR and the serum concentration of estradiol-17p are closely correlated with the sexual cycle (Fernandez et al, 1984). Concomitantly, we demonstrated that the ultrastructure of oviducal epithelium exhibited seasonal changes according to the ovarian cycle, indicating modulation by steroid hormones (Fernandez et al, 1989a).…”

“…Administration of estradiol-17P (E,), 5 a-dihydrotestosterone (DHT), or testosterone (T), but not progester-0 1994 WILEY-LISS, INC. one (P), induced the proliferation of secretory cells with the development of structures associated with the synthesis of the secretory material into the granules (Fernandez et al, 198913) and the reappearance of biological activity (Fernandez et al, 1984). In accordance with these data we had found that estradiol-17P stimulated the synthesis of PR proteins in either in vivo or in vitro conditions (Mansilla-Whitacre et al, 1992).…”

“…Concomitantly, we demonstrated that the ultrastructure of oviducal epithelium exhibited seasonal changes according to the ovarian cycle, indicating modulation by steroid hormones (Fernandez et al, 1989a). In fact, ovariectomy determined regressive effects in Bufo arenarum PR, inducing cellular involution of the epithelial layer with the disappearance of granules in secretory cells (Fernandez et al, 1989b), in agreement with the diminution of PR activity and estradiol circulating levels (Fernandez et al, 1984).…”

Nuclear maturation inducers in Bufo arenarum oocytes

“…Even though progesterone is considered to be the hormone that physiologically triggers meiotic resumption in amphibians (Jalabert et al, 1991), our observations demonstrate that DHT, an androgen with extremely high circulating levels in Bufo arenarum females (Fernández et al, 1984), is also capable of inducing nuclear maturation, its action being dose-and time-dependent.…”