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Plasma E2 (plasma + e2)
Selected AbstractsTime-Dependent transcriptional profiles of genes of the hypothalamic-pituitary-gonadal axis in medaka (Oryzias latipes) exposed to fadrozole and 17,-trenboloneENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 12 2008Xiaowei Zhang Abstract Both the anabolic androgen 17,-trenbolone (TRB) and the aromatase inhibitor fadrozole (FAD) can cause decreased plasma concentrations of estrogen (E2) and reduce fecundity of fish. However, the underlying mechanisms and the molecular pathways involved are largely unknown. The present study was designed to assess time-dependent effects of FAD and TRB on the transcriptional responses of the hypothalamic-pituitary-gonadal (HPG) axis of Japanese medaka (Oryzias latipes). Fourteen-week-old Japanese medaka were exposed to 50 ,g FAD/L or 2 ,g TRB/L in a 7-d static renewal test, and the expression profiles of 36 HPG axis genes were measured by means of a medaka HPG real-time reverse-transcription polymerase chain reaction array after 8 h, 32 h, or 7 d of exposure. Exposure to TRB or FAD caused lesser fecundity of Japanese medaka and down-regulated transcription of vitellogenin and choriogenin (CHG) gene expression in the liver of females. Exposure to FAD for 8 h resulted in an 8-fold and 71-fold down-regulation of expression of estrogen receptor , and choriogenin L (CHG L), respectively, in female liver. 17,-Trenbolone caused similar down-regulation of these genes, but the effects were not observed until 32 h of exposure. These results support the hypothesis that FAD reduces plasma E2 more quickly by inhibiting aromatase enzyme activity than does TRB, which inhibits the production of the E2 precursor testosterone. Exposure to FAD and TRB resulted in rapid (after 8 h) down-regulation of luteinizing hormone receptor and low-density-lipoprotein receptor in the testis to compensate for excessive androgen levels. Overall, the molecular responses observed in the present study differentiate the mechanisms of the reduced fecundity by TRB and FAD. [source] Estrogen-dependent selectivity of genomic responses to birdsongEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 6 2006Donna L. Maney Abstract Behavioral responses to sociosexual signals often depend on gonadal steroid hormones, which are thought to modulate behavior by acting on motivational systems in the brain. There is mounting evidence that sex steroids may also modulate perception of sociosexual signals by affecting sensory processing. In seasonally breeding songbirds such as the white-throated sparrow (Zonotrichia albicollis), the female's behavioral response to hearing male song depends on her plasma levels of estradiol (E2). Here, we examined whether plasma E2 also affects the selectivity of the song-induced zenk (egr-1) response in the auditory forebrain, which is known to vary according to the behavioral relevance of song stimuli. Non-breeding females were held on a winter-like photoperiod and implanted with silastic capsules containing either no hormone or E2. E2-treated birds hearing 42 min of conspecific song had more cells immunoreactive for the protein product of zenk in the auditory forebrain than did those hearing frequency-matched synthetic tones. In birds not treated with E2, however, the zenk response to song did not differ from that to tones. We found similar effects in the avian homolog of the inferior colliculus, indicating that E2 may affect the processing of auditory information upstream of the forebrain. Our data suggest that in females, zenk induction in the auditory system is selective for song only when plasma E2 exceeds non-breeding levels. E2-dependent plasticity of auditory pathways and processing centres may promote recognition of and attention to conspecific song during the breeding season. [source] Endocrine Profiles and Embryo Quality in Japanese Black Cattle Superovulated with Human Menopausal Gonadotrophin and Porcine Follicle Stimulating HormoneREPRODUCTION IN DOMESTIC ANIMALS, Issue 2 2001M Sugano Induction of superovulation using human menopausal gonadotriphin (hMG) in Japanese Black cattle can result in the recovery of a higher percentage of high quality embryos compared with that using porcine follicle stimulating hormone (FSH). In order to clarify the endocrinological mechanism involved in this discrepancy, 30 superovulation sessions of 17 Japanese Black cattle were studied. Fifteen cattle were super-stimulated with hMG (total 600 IU), and the remaining 15 cattle were given FSH (total 20 mg). The plasma profiles of LH, estradiol-17, (E2) and progesterone (P4) were correlated, and the embryo quality was investigated. The total number of ova recovered and the number of transferable embryos tended to be larger in the hMG-treated group than in the FSH-treated group. The percentage of excellent embryos tended to be higher in the hMG-treated group than in the FSH-treated group (54.3 and 28.7%, respectively, p < 0.10). The E2 level increased during the first 3 days after the initial administration of either hMG or FSH and was higher in the hMG-treated group than in the FSH-treated group (p < 0.05). During this period, the E2 level could be categorized into one of the following three types according to whether it increased or decreased and according to the degree of increase or decrease: (1) increase by a factor of 1.2 or more (quick increase type) (2) slight increase by a factor less than 1.2 (slow increase type), and (3) no increase (unstable increase type). In the group treated with hMG, 66.7% of the animals (10 of 15 cattle) showed a quick increase in the E2 level. However, in the FSH-treated group, 40% (six of 15) of the animals showed a slow increase in the E2 level. The plasma LH level increased dramatically 8 h prior to the peak level in both the hMG- and FSH-treated groups, and then it returned to the basal level 12 h later. After the administration of prostaglandin (PG)F2,, the LH peak level was attained within 44 h in 80% of the animals in the hMG-treated group, whereas in the FSH-treated group, the LH peak level tended to be reached later. The P4 level did not increase during the period of hMG or FSH treatment and decreased drastically following administration of PGF2,. After the onset of oestrus, the P4 level was higher in the hMG group than in the FSH group, and 5 to 7 days after oestrus, the level remained higher in the hMG group than in the FSH group (p < 0.05). After the first 3 days of hMG administration, the E2/P4 ratio was higher than that after FSH administration. Furthermore, on the day following PGF2, administration, the ratio was significantly higher in the hMG group than in the FSH group (p < 0.05). These results indicate that superovulation in cattle given hMG results in a significant increase in plasma E2 during the first 3 days and that the increase in the plasma P4 level is larger a few days after oestrus and thereafter compared with FSH-induced superovulation. Therefore, such plasma level profiles may be related to the increased recovery rate of high quality embryos. [source] Measurement of urinary and fecal steroid metabolites during the ovarian cycle in captive and wild Japanese macaques, Macaca fuscataAMERICAN JOURNAL OF PRIMATOLOGY, Issue 4 2001Shiho Fujita Abstract We measured the concentration of steroid hormones from urine, feces, and blood samples of two captive Japanese macaques, Macaca fuscata, during nonconceptive ovarian cycles to compare the patterns of the excreted steroids with those of circulating steroids. Urine and feces were analyzed for estrone conjugates (E1C) and pregnanediol-3-glucronide (PdG) using enzyme immunoassays (EIAs), while plasma was analyzed for estradiol-17,(E2), progesterone (P), and luteinizing hormone (LH) using radioimmunoassays (RIAs). Urinary and fecal E1C and PdG levels were approximately parallel to plasma E2 and P levels, respectively. The E1C profiles of daily urinary and fecal samples revealed a midcycle peak, followed by a sustained PdG increase lasting up to two weeks from the E1C peak. A fecal E1C peak was one day later than the urinary E1C peak. One of the captive females exhibited a discrete plasma LH peak, one indicator that ovulation has occurred, on the day following the urinary E1C peak, i.e., the same day of fecal E1C peak. We measured excreted steroids in nine wild females and determined the timing of ovulation by comparing fecal steroid profiles to those obtained in captive monkeys. Data from wild females indicated that eight of nine females conceived during their first ovulatory cycle of the sampling period, whereas the remaining female failed to conceive during the sampling period even though she ovulated. In the eight females that conceived, E1C increased again following the detected or estimated E1C peak, with levels comparable to the preovulatory peak levels, and sustained elevations of PdG for over 40 days. These data illustrate that the urinary and fecal profiles of ovarian steroid excretion obtained through the application of these noninvasive techniques provide an accurate approach for monitoring conceptive and nonconceptive ovarian cycle in captive and free-living Japanese macaques. Am. J. Primatol. 53:167,176, 2001. © 2001 Wiley-Liss, Inc. [source] Capture and handling stress affects the endocrine and ovulatory response to exogenous hormone treatment in snapper, Pagrus auratus (Bloch & Schneider)AQUACULTURE RESEARCH, Issue 11 2002J J Cleary Abstract Sexually mature female hatchery-reared snapper, Pagrus auratus (Bloch & Schneider) were captured from sea cages by handline and injected at first capture (control) or 24 h after capture, transport and subsequent confinement (delayed injection) with either saline, luteinizing hormone releasing hormone analogue, human chorionic gonadotropin, or 17,-hydroxyprogesterone. Blood was sampled before hormone treatment and again after 168 h, and fish were checked daily for ovulation. Plasma levels of 17,-estradiol (E2), testosterone (T), 17,, 20, dihydroxy-4-pregnen-3-one (17, 20,P) and cortisol were determined by radioimmunoassay. The ovulatory response was assessed from the proportion of fish ovulating, ovulation volume, egg quality and fertility. A delay in injection resulted in significantly lower plasma E2 and T levels in response to hormone treatment, smaller ovulation volumes, and poorer egg quality than in control fish. The results are consistent with the generally inhibitory effects of stress on reproduction in fish, and confirm the requirement to treat fish with hormones designed to induce ovulation, as soon as possible after capture and disturbance. [source] | ||||||||||