1
|
Gbotolorun SC, Inikori O, Bamisi OD, Osinubi AAA, Okanlawon AO. Quinine inhibits ovulation and produces oxidative stress in the ovary of cyclic Sprague-Dawley rats. Afr Health Sci 2018; 18:253-259. [PMID: 30602950 PMCID: PMC6306975 DOI: 10.4314/ahs.v18i2.8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/06/2022] Open
Abstract
BACKGROUND Quinine has been reported to possess anti-spermatogenic activities. OBJECTIVES This study was carried out to determine the effect of quinine on ovarian function in Sprague-Dawley rats. METHODS Twenty rats with regular 4-days oestrous cycle divided into 4 groups (N=5) were used. Group I received quinine at 30 mg/kg body weight by gavage for 28 days after which they were sacrificed. The ovaries were excised for biochemical oxidation of glutathione peroxidase (GSH), superoxide dismutase (SOD), catalase and malondialdehyde (MDA). Group II received single dose quinine at 30 mg/kg body weight at 0900 hrs on day of proestrus. Blood was obtained at 1800 hrs for hormonal assay of FSH and LH. The animals were sacrificed the next morning on estrus: oviducts were examined for ova count. Groups III and IV served as controls. RESULTS Quinine treated rats recorded zero number of ova compared to control. Serum concentration of LH reduced significantly in the quinine treated group compared to the control. Furthermore, quinine significantly decreased the oxidant status of GSH, SOD and catalase and significantly increased MDA levels in the ovary compared to the control group. CONCLUSION Quinine completely blocks ovulation, suppresses LH surge, and produces oxidative stress in the ovary.
Collapse
Affiliation(s)
- Stella Chinwe Gbotolorun
- Department of Anatomy, Faculty of Basic Medical Sciences, College of Medicine of the University of Lagos, Nigeria
| | - Oghenevwakpeje Inikori
- Department of Anatomy, Faculty of Basic Medical Sciences, College of Medicine of the University of Lagos, Nigeria
| | - Olawande Damilola Bamisi
- Department of Anatomy, Faculty of Basic Medical Sciences, College of Medicine of the University of Lagos, Nigeria
| | | | - Abayomi Olugbenga Okanlawon
- Department of Anatomy, Faculty of Basic Medical Sciences, College of Medicine of the University of Lagos, Nigeria
| |
Collapse
|
2
|
JAROENPORN S, HORII Y, AKIEDA-ASAI S, WANG K, NAGAOKA K, OHTA R, SHIROTA M, WATANABE G, TAYA K. Endocrine Mechanisms Responsible for Different Follicular Development During the Estrous Cycle in Hatano High- and Low-avoidance Rats. J Reprod Dev 2011; 57:690-9. [DOI: 10.1262/jrd.10-160s] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Sukanya JAROENPORN
- Primate Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Yasuyuki HORII
- Department of Basic Veterinary Science, The United Graduate School of Veterinary Sciences, Gifu University, Gifu 501-1193, Japan
- Laboratory of Veterinary Physiology, Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo 183-8509, Japan
| | - Sayaka AKIEDA-ASAI
- Frontier Science Research Center, University of Miyazaki, Miyazaki 889-1692, Japan
| | - KaiMing WANG
- Laboratory of Veterinary Physiology, Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo 183-8509, Japan
| | - Kentaro NAGAOKA
- Department of Basic Veterinary Science, The United Graduate School of Veterinary Sciences, Gifu University, Gifu 501-1193, Japan
- Laboratory of Veterinary Physiology, Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo 183-8509, Japan
| | - Ryo OHTA
- Division of Toxicology, Hatano Research Institute, Food and Drug Safety Center, Kanagawa 257-8523, Japan
| | - Mariko SHIROTA
- Laboratory of Comparative Toxicology, School of Veterinary Medicine, Azabu University, Kanagawa 229-8501, Japan
| | - Gen WATANABE
- Department of Basic Veterinary Science, The United Graduate School of Veterinary Sciences, Gifu University, Gifu 501-1193, Japan
- Laboratory of Veterinary Physiology, Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo 183-8509, Japan
| | - Kazuyoshi TAYA
- Department of Basic Veterinary Science, The United Graduate School of Veterinary Sciences, Gifu University, Gifu 501-1193, Japan
- Laboratory of Veterinary Physiology, Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo 183-8509, Japan
| |
Collapse
|
3
|
KANDIEL MM, WATANABE G, ABDEL-GHAFFAR AE, SOSA GA, ABOU-EL ROOS MEA, EL-AZAB AESI, LI JY, MANABE N, TAYA K. Ovarian Follicular Dynamics and Hormonal Changes in Goats during Early Pregnancy. J Reprod Dev 2010; 56:520-6. [DOI: 10.1262/jrd.09-179t] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Mohamed M.M. KANDIEL
- Laboratory of Veterinary Physiology, Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology
- Department of Theriogenology, Faculty of Veterinary Medicine, Benha University
| | - Gen WATANABE
- Laboratory of Veterinary Physiology, Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology
- Department of Basic Veterinary Science, The United Graduate School of Veterinary Sciences, Gifu University
| | | | - Gamal A. SOSA
- Department of Theriogenology, Faculty of Veterinary Medicine, Benha University
| | | | | | - Jun Y. LI
- Animal Resource Science Center, Graduate School of Agriculture and Life Science, University of Tokyo
| | - Noboru MANABE
- Animal Resource Science Center, Graduate School of Agriculture and Life Science, University of Tokyo
| | - Kazuyoshi TAYA
- Laboratory of Veterinary Physiology, Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology
- Department of Basic Veterinary Science, The United Graduate School of Veterinary Sciences, Gifu University
| |
Collapse
|
4
|
Hatsuta M, Abe K, Tamura K, Ryuno T, Watanabe G, Taya K, Kogo H. Effects of hypothyroidism on the estrous cycle and reproductive hormones in mature female rat. Eur J Pharmacol 2005; 486:343-8. [PMID: 14985057 DOI: 10.1016/j.ejphar.2003.12.035] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2003] [Revised: 12/11/2003] [Accepted: 12/19/2003] [Indexed: 11/21/2022]
Abstract
The present study was undertaken to examine the systemic role of thyroid hormones by analyzing changes in reproductive functions in hypothyroid female rats. Serum concentrations of triiodo-thyronine (T3) significantly decreased 1 week after the initiation of propyl-thiouracil treatment or thyroidectomy. The estrous cycle became irregular 3 and 2 weeks after the initiation of propyl-thiouracil treatment and thyroidectomy, respectively. Serum luteinizing hormone (LH) levels significantly reduced in both groups on the day of diestrus-1 about 1 month later. Hypothyroid rat shows the high progesterone and low testosterone levels. No significant changes in inhibin and estradiol levels were detected. The serum levels of FSH decreased in the thyroidectomy group. The irregular estrous cycle and the above changes in hormone levels were recovered by administration of T4. Compensatory secretions of FSH and LH induced by ovariectomy were enhanced by thyroidectomy and suppressed by T4 treatment. These results suggest that thyroid hormones play a role in the regulation of reproductive hormones secretion in the cyclic rat ovary.
Collapse
Affiliation(s)
- Minoru Hatsuta
- Department of Pharmacology, Tokyo University of Pharmacy and Life Science, 1432-1, Horinouchi, Hachioji, Tokyo 192-0392, Japan
| | | | | | | | | | | | | |
Collapse
|
5
|
Tohei A. Studies on the functional relationship between thyroid, adrenal and gonadal hormones. J Reprod Dev 2004; 50:9-20. [PMID: 15007197 DOI: 10.1262/jrd.50.9] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In order to clarify the functional relationship between thyroid, adrenal and gonadal hormones, hypothyroidism was induced by administration of thiuoracil in adult male and female rats, and the effects of hypothyroidism on the adrenal and the gonadal axes were investigated in the present study. 1. The functional relationship between thyroid and adrenal hormones: Adrenal weights and corticosterone were lowered, whereas the secretion of ACTH, corticotrophin-releasing hormone (CRH) and arginine vasopressin (AVP) increased in hypothyroid rats compared to euthyroid rats. These results indicate that hypothyroidism causes adrenal dysfunction directly and results in hypersecretion of CRH and AVP from the hypothalamus. 2. The functional relationship between thyroid and gonadal hormones: The pituitary response to LHRH was lowered, whereas the testicular response to hCG was not changed in hypothyroid rats. Hypothyroidism suppressed copulatory behavior in male rats. These results suggest that hypothyroidism probably causes dysfunction in gonadal axis at the hypothalamic-pituitary level in male rats. In adult female rats, hypothyroidism inhibited the follicular development accompanied estradiol secretion, whereas plasma concentrations of progesterone and prolactin (PRL) increased in hypothyroid female rats. Hypothyroidism significantly increased the pituitary content of vasoactive intestinal peptide (VIP) though it did not affect dopamine synthesis. These results suggest that hypothyroidism increases pituitary content of VIP and this increased level of VIP likely affects PRL secretion in a paracrine or autocrine manner. In female rats, inhibition of gonadal function in hypothyroid rats mediated by hyperprolactinemia in addition to hypersecretion of endogenous CRH.
Collapse
Affiliation(s)
- Atsushi Tohei
- Laboratory Animal Research Center, Dokkyo University School of Medicine, 880 Kitakobayashi, Mibu, Tochigi 321-0293, Japan.
| |
Collapse
|
6
|
Ishigame H, Medan MS, Watanabe G, Shi Z, Kishi H, Arai KY, Taya K. A new alternative method for superovulation using passive immunization against inhibin in adult rats. Biol Reprod 2004; 71:236-43. [PMID: 15031144 DOI: 10.1095/biolreprod.104.027789] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The present study was undertaken to investigate the effects of passive immunoneutralization of endogenous inhibin on ovulation rate and embryo development in vivo and in vitro to establish a new alternative superovulation method in the adult rat. Female adult rats of Wistar strain were superovulated with a single injection of inhibin antiserum (inhibin-AS; 100 or 400 microl) or an injection of 20 IU eCG followed by an injection of 10 IU hCG. Untreated animals served as controls. Embryos were collected from oviducts or uteri on Days 1-5 of pregnancy, and the number of embryos and implantation sites were observed. On Day 1 of pregnancy, the two-cell-stage embryos were cultured and embryos from the 100-microl inhibin-AS group and the control group were transferred to recipient females to determine developmental competence. There were no significant differences between groups in fertilization rate. The numbers of normal embryos in the inhibin-AS-treated groups were significantly higher than the control and the eCG-hCG-treated groups throughout Days 1-4 of pregnancy. The number of implantation sites observed on Day 5 of pregnancy in the inhibin-AS-treated groups was significantly higher than both the control and the eCG-hCG-treated groups. Furthermore, the rate of blastocyst development in vitro in the inhibin-AS-treated groups and posttransfer viability in the 100-microl-inhibin-AS group were comparable with those of the control group. These results indicate that immunoneutralization of endogenous inhibin is a new practical alternative for induction of superovulation as a substitution for eCG-hCG method in the adult rat.
Collapse
Affiliation(s)
- Harumichi Ishigame
- Laboratory of Veterinary Physiology, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan
| | | | | | | | | | | | | |
Collapse
|
7
|
Gao X, Petroff BK, Oluola O, Georg G, Terranova PF, Rozman KK. Endocrine disruption by indole-3-carbinol and tamoxifen: blockage of ovulation. Toxicol Appl Pharmacol 2002; 183:179-88. [PMID: 12383709 DOI: 10.1006/taap.2002.9478] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Immature Sprague-Dawley rats received daily doses of indole-3-carbinol (I3C, 0-1.5 g/kg/day), 3,3'-diindolymethane (DIM, 0-400 mg/kg/day), tamoxifen (TAM, 0-0.5 mg/kg/day), or vehicle to determine if their antiestrogenic effects occur by the same mechanism and whether I3C's action is mediated by DIM. Follicular development was induced on day 24 of age by equine chorionic gonadotropin (eCG, 5 IU) 1 day after the initial dose. In a hormone replacement study, human chorionic gonadotropin (hCG, 10 IU sc, 48 h post-eCG) was used to mimic a normal preovulatoy luteinizing hormone (LH) surge following treatment with either I3C or TAM. Blood and ovaries were collected throughout follicular development and the number of ova shed was measured on the morning following expected ovulation (72 h post-eCG). I3C but not TAM reduced body weight gain at higher doses after 4 days of dosing. Ovarian weight gain and ovulation were inhibited by both I3C and TAM in a dose-dependent fashion. During the preovulatory period, both I3C and TAM blocked normal LH and follicle-stimulating hormone (FSH) surges and suppressed serum progesterone (P(4)) profoundly without changing circulating levels of estrogen (E(2)). At the time of expected ovulation, serum E(2) was increased in rats receiving I3C or tamoxifen, whereas serum P(4) was dose-dependently decreased. DIM exerted no significant effects on any of the endpoints studied, even at the highest dose, indicating that the antiestrogenic effects of I3C are not mediated by this metabolite of I3C. hCG successfully restored ovarian weight gain and ovulation in TAM-treated rats. However, hCG only partially reversed the blockage of ovulation by I3C, although ovarian weight gain was restored to normal. In summary, both I3C and TAM block ovulation by altering preovulatory concentrations of LH and FSH, but I3C appears to exert its effect(s) by (a) different mechanism(s) of action. I3C seems to act at both the ovarian and hypothalamic levels by mechanisms similar to those seen in TCDD-treated rats, whereas TAM appears to act only on the hypothalamic-pituitary axis as an anti-estrogen.
Collapse
Affiliation(s)
- Xin Gao
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City 66160, USA
| | | | | | | | | | | |
Collapse
|
8
|
OHSHIMA KI, ITOH M, KISHI H, WATANABE G, JIN W, SAITA E, K. SUZUKI A, TERRANOVA PF, TAYA K. Roles of Basal Levels of Circulating Luteinizing Hormone on Follicular Maturation in the Pregnant Golden Hamster (Mesocricetus auratus). J Reprod Dev 2002. [DOI: 10.1262/jrd.48.363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Ken-ichi OHSHIMA
- Laboratory of Veterinary Physiology, Tokyo University of Agriculture and Technology
- Tissue Physiology and Laboratory of Animal Science, Tokyo University of Agriculture and Technology
| | - Mariko ITOH
- Department of Cellular and Molecular Biology, Primate Research Institute, Kyoto University
| | - Hisashi KISHI
- Genome Research Department, National Institute of Agrobiological Sciences
| | - Gen WATANABE
- Laboratory of Veterinary Physiology, Tokyo University of Agriculture and Technology
- Department of Basic Veterinary Science, The Graduate School of Veterinary Sciences, Gifu University
| | - WanZhu JIN
- Laboratory of Veterinary Physiology, Tokyo University of Agriculture and Technology
- Department of Basic Veterinary Science, The Graduate School of Veterinary Sciences, Gifu University
| | - Erina SAITA
- Laboratory of Veterinary Physiology, Tokyo University of Agriculture and Technology
- Department of Basic Veterinary Science, The Graduate School of Veterinary Sciences, Gifu University
| | - Akira K. SUZUKI
- Air Pollutants Health Effects Research Team, Environmental Risk Assessment Project, National Institute for Environmental Studies
| | - Paul F. TERRANOVA
- Center for Reproductive Sciences, University of Kansas Medical Center
| | - Kazuyoshi TAYA
- Laboratory of Veterinary Physiology, Tokyo University of Agriculture and Technology
- Department of Basic Veterinary Science, The Graduate School of Veterinary Sciences, Gifu University
| |
Collapse
|
9
|
Ozawa M, Shi F, Watanabe G, Suzuki AK, Taya K. Regulatory role of inhibin in follicle-stimulating hormone secretion and folliculogenesis in the guinea pig. J Vet Med Sci 2001; 63:1091-5. [PMID: 11714024 DOI: 10.1292/jvms.63.1091] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The effects of unilateral and bilateral ovariectomy and passive immunization against inhibin on follicle-stimulating hormone (FSH) secretions and follicular development in the guinea pig were investigated. Bilateral ovariectomy decreased plasma immunoreactive (ir-) inhibin rapidly and increased plasma FSH significantly. Unilateral ovariectomy decreased plasma ir-inhibin and increased plasma FSH temporarily, and doubled the number of ova released from the remaining ovary at the subsequent ovulation in guinea pigs. Injection of 1.0 ml inhibin antiserum significantly increased concentrations of plasma FSH at 6 hr onwards and the number of small follicles (100-200 microm in diameter) at 48 hr after the injection in guinea pigs bearing progesterone-containing implants. In vitro bioassay showed that inhibin antiserum could neutralize the suppression of ovarian homogenate on FSH secretion from cultured rat anterior pituitary cells. These results confirm the evidence that the ovary is the main source of inhibin secretion and both in vitro bioassay and passive immunization against inhibin show that the inhibin is a major regulator in the follicular development through FSH secretion in guinea pigs.
Collapse
Affiliation(s)
- M Ozawa
- Laboratory of Veterinary Physiology, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | | | | | | | | |
Collapse
|
10
|
Gao X, Mizuyachi K, Terranova PF, Rozman KK. 2,3,7,8-tetrachlorodibenzo-p-dioxin decreases responsiveness of the hypothalamus to estradiol as a feedback inducer of preovulatory gonadotropin secretion in the immature gonadotropin-primed rat. Toxicol Appl Pharmacol 2001; 170:181-90. [PMID: 11162783 DOI: 10.1006/taap.2000.9099] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sprague-Dawley rats (23-day-old) were dosed with TCDD (32 microg/kg) in corn oil or vehicle alone. Equine chorionic gonadotropin (eCG) was injected (5 IU, sc) 24 h later to induce follicular development. Another 24 h later, half of TCDD- or corn oil-treated rats were injected (sc) with 17 beta-estradiol-cypionate (ECP, at 0.004 to 0.5 mg/kg). Blood and ovaries were collected on expected proestrous (preovulatory period) at 51, 54, and 58 h after eCG injection as well as in the morning after ovulation (72 h after eCG). Serum concentrations of 17 beta-estradiol (E), progesterone (P), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) were determined by radioimmunoassay. The number of ova shed was measured at 72 h after injection of eCG by irrigating ova from oviducts. During the preovulatory period (approximately 58 h after eCG injection), a circulating level of 70-100 pg E/ml coincided with LH and FSH surges and later normal ovulation of 10 to 12 ova/rat was observed in controls. However, the same concentration of E was not associated with LH and FSH surges in rats treated with TCDD (32 microg/kg), resulting in reduced ovarian weight gain and reduction of ovulation by 70 to 80% (2-3 ova/rat). Blockage of the gonadotropin surge, reduced ovarian weight gain, and ovulation were all reversed completely by the lowest effective dose of ECP (0.1 mg/kg). At 72 h after eCG, serum P secretion was reduced and serum E levels were significantly increased compared to those of corn oil-treated controls. ECP alone had no effect on serum P levels at any time point, but in rats treated with TCDD and ECP, both the reduction of P (at 58 and 72 h) and the increase in E secretion (72 h) were completely reversed. Further studies confirmed that restoration by ECP of gonadotropin surges and associated ovulation could not be attained until circulating levels of E rose sufficiently high to trigger the LH and FSH surges. The new action threshold of E for inducing gonadotropin surges in rats treated with TCDD (32 microg/kg) was determined to be eight- to 10-fold higher than that in controls. Thus, it is apparent that TCDD decreased the responsiveness of the hypothalamus to E as a feedback inducer of preovulatory gonadotropin secretion.
Collapse
Affiliation(s)
- X Gao
- Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas 66160, USA
| | | | | | | |
Collapse
|
11
|
Gao X, Petroff BK, Rozman KK, Terranova PF. Gonadotropin-releasing hormone (GnRH) partially reverses the inhibitory effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin on ovulation in the immature gonadotropin-treated rat. Toxicology 2000; 147:15-22. [PMID: 10837928 DOI: 10.1016/s0300-483x(00)00161-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Several studies have shown that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) has inhibitory effects on ovulation. This action may be the result of either direct effect(s) of TCDD on ovarian function or via altered secretion of pituitary luteinizing hormone (LH) and follicle stimulating hormone (FSH) which regulate ovarian follicular development and ovulation. To further evaluate the effects of TCDD on pituitary gonadotropins and their regulation, the potential role of gonadotropin-releasing hormone (GnRH) was investigated in the current study. Immature (23-day-old) female Sprague-Dawley rats were dosed with TCDD (32 microg/kg) in corn oil or vehicle alone. Equine chorionic gonadotropin (eCG) was injected subcutaneously (5 IU, sc) 24 h later to induce follicular development. Immediately prior to the expected time of the LH/FSH surges, 54 h after eCG injection, half of TCDD- or corn oil-treated rats were injected with GnRH (2 microg/rat, sc). Blood and ovaries were collected at 54, 56, 58, 60 and 72 h after eCG. Serum concentrations of 17beta-estradiol (E(2)), progesterone (P(4)), LH, and FSH were determined by radioimmunoassay. An indication of ovulation rate was assessed at 72 h after injection of eCG by irrigating the ova from oviducts. TCDD reduced the number of ova in the oviducts by 70-80% (2-3 ova/rat) and this was confirmed by the number of corpora lutea. GnRH partially restored ovulation (6-7 ova/rat) in TCDD-treated rats without reversing its effect on ovarian weight reduction. In controls, the LH and FSH surges at 58 h after eCG were significantly reduced at that time in TCDD-treated rats. However, in rats treated with TCDD and GnRH, a huge LH/FSH surges occurred at 56 h after eCG injection. GnRH alone enhanced E(2) and P(4) serum levels at 56-58 h after eCG injection. In rats treated with both TCDD and GnRH, E(2) secretion was significantly lower at 58, 60, and 72 h when compared with GnRH alone, whereas serum P(4) was only decreased at 72 h after eCG injection. The results indicate that exogenous GnRH induces LH and FSH surges in TCDD-treated rats, but only partially restores the inhibitory effects of TCDD on ovulation.
Collapse
Affiliation(s)
- X Gao
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160-7417, USA
| | | | | | | |
Collapse
|
12
|
Gao X, Terranova PF, Rozman KK. Effects of polychlorinated dibenzofurans, biphenyls, and their mixture with dibenzo-p-dioxins on ovulation in the gonadotropin-primed immature rat: support for the toxic equivalency concept. Toxicol Appl Pharmacol 2000; 163:115-24. [PMID: 10698669 DOI: 10.1006/taap.1999.8851] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous studies have shown that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 1,2,3,7,8-pentachlorodibenzo-p-dioxin (PeCDD), and 1,2,3,4,7, 8-hexachlorodibenzo-p-dioxin (HxCDD), and their equipotent mixture block ovulation, reduce ovarian weight gain and alter preovulatory hormone levels in a similar manner. The objective of the current experiment was to investigate the effect of other structurally related compounds such as chlorinated furans and biphenyls on ovulation and related hormonal endpoints. The gonadotropin-primed immature female rat model was used to study the effect of 2,3,4,7, 8-pentachlorodibenzofuran (PeCDF), 3,3',4,4',5-pentachlorobiphenyl (PeCB), and 2,2',5,5' tetrachlorobiphenyl (TCB) and their mixture with polychlorinated dibenzo-p-dioxins (PCDDs) on ovulation. Rats were dosed on Day 23 of age at 0900 h with individual congeners (PeCDF, PeCB, TCB) or a mixture of five compounds, which included TCDD, PeCDD, HxCDD, in addition to PeCDF and PeCB. Equine choronic gonadotropin (eCG; 5 IU) was injected 24 h later to induce follicular development. Blood and ovaries were harvested, and ovarian weights determined at various times after eCG. Serum concentrations of 17beta-estradiol (E(2)), progesterone (P(4)), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) were determined by radioimmunoassay. At 72 h after injection of eCG, the number of ova shed was measured by irrigating the ova from oviducts. The slopes of the dose-responses for inhibition of ovulation generated by the individual PeCDF, PeCB, and/or their mixture with PCDDs were similar. PeCDF, PeCB, and the mixture increased serum concentrations of E(2) at 72 h after eCG injection, the day of expected ovulation; in contrast, serum P(4) and FSH were decreased at that same time point. Only the high doses of TCDD, PeCDF, and PeCB blocked LH and FSH surges at 58 h after eCG. The ovarian histology revealed that the effects of PeCDF, PeCB, and the mixture were very similar to those of PCDDs, consisting of ova in large preovulatory follicles and a lack of or reduced number of corpora lutea. Parallel dose-responses of the individual congeners (PeCDF and PeCB) and their equipotent mixture with PCDDs support the toxic equivalency (TEQ) concept for the blockage of ovulation. Thus, PCDDs, PCDFs, and PeCBs appear to block ovulation by the same or a very similar mechanism of action.
Collapse
Affiliation(s)
- X Gao
- Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas 66160, USA
| | | | | |
Collapse
|
13
|
Gao X, Son DS, Terranova PF, Rozman KK. Toxic equivalency factors of polychlorinated dibenzo-p-dioxins in an ovulation model: validation of the toxic equivalency concept for one aspect of endocrine disruption. Toxicol Appl Pharmacol 1999; 157:107-16. [PMID: 10366543 DOI: 10.1006/taap.1999.8649] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Polychlorinated dibenzo-p-dioxins (PCDDs) are structural analogues, which produce a similar spectrum of biological and toxicological responses in animals, albeit with differential potencies. Very consistent structure-activity relationships have been found for acute toxicity and some biochemical effects among these compounds. For the current experiments, the gonadotropin-primed immature female rat model was used to study the effect of 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD), 1,2,3,7, 8-pentachlorodibenzo-p-dioxin (PeCDD), and 1,2,3,4,7, 8-hexachlorodibenzo-p-dioxin (HxCDD) on ovulation. Single doses of different PCDDs and their mixture were given orally to 23-day-old rats. Gonadotropin from pregnant mare's serum (PMSG) was injected (5 IU) 24 h later to induce follicular maturation. Rats were decapitated at various times after PMSG, blood was collected, and ovarian weight was measured. Serum concentrations of 17beta-estradiol (E2), progesterone (P4), luteinizing hormone (LH), follicle stimulating hormone (FSH), and prolactin (PrL) were determined by radioimmunoassay. Ovulation was measured at 72 h after injection of PMSG by counting ova flushed from oviducts. PCDDs dose dependently decreased the number of ova per ovary and reduced ovarian weight gain induced by PMSG. The slopes of the dose-response curves generated by individual PCDDs and/or their mixture were similar. PMSG-induced increase in serum E2 was enhanced on the day of expected ovulation by PCDDs; in contrast, serum P4 and FSH were decreased at that same time point. PCDDs also altered the temporal pattern of serum E2, FSH, and LH but not that of PrL. Histologically the effect of all three PCDDs consisted of ova trapped in preovulatory follicles and a lack of or reduced number of corpora lutea. The results indicate that the PCDDs, tested in the present model, have the same mode of action on ovulation and the reproductive hormones, e.g., LH, FSH, P4 and E2. Furthermore, the dose responses of the individual congeners are parallel to each other and also to that of their equipotent mixture, which represent a validation of the TEQ concept for one aspect of endocrine disruption, that is for inhibition of ovulation.
Collapse
Affiliation(s)
- X Gao
- Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas, 66160, USA
| | | | | | | |
Collapse
|
14
|
Tohei A, Imai A, Watanabe G, Taya K. Influence of thiouracil-induced hypothyroidism on adrenal and gonadal functions in adult female rats. J Vet Med Sci 1998; 60:439-46. [PMID: 9592715 DOI: 10.1292/jvms.60.439] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The effect of hypothyroidism on adrenals and gonads in adult female rats was investigated throughout the estrous cycle. Hypothyroidism was induced by administration of 4-Methyl-2-Thiouracil (Thiouracil) in the drinking water. The weight of ovaries and adrenals, and the plasma levels of corticosterone decreased in hypothyroid rats as compared with euthyroid rats throughout the estrous cycle. Hypothyroidism resulted in decreased concentrations of plasma LH on the day of diestrus and proestrus, whereas the plasma concentrations of prolactin and progesterone increased as compared with euthyroid rats. The weight of uteri and plasma concentrations of estradiol decreased during the day of diestrus and proestrus in hypothyroid rats as compared with euthyroid rats. To further clarify the dysfunction of hypothalamo-hypophysial-adrenal axis in hypothyroid rats, animals were stressed by immobilization for 3 hr. In hypothyroid rats, a marked increase in plasma levels of ACTH in response to immobilization stress was observed compared to euthyroid control, whereas increases in plasma concentrations of corticosterone were much smaller in hypothyroid than euthyroid rats. These results clearly indicate that hypothyroidism causes both gonadal and adrenal disturbances in adult female rats. The increased concentrations of plasma progesterone may be due to hypersecretion of prolactin during the day of proestrus and estrus, which in turn result in disruption of the estrous cycle.
Collapse
Affiliation(s)
- A Tohei
- Laboratory of Veterinary Physiology, Tokyo University of Agriculture and Technology, Japan
| | | | | | | |
Collapse
|
15
|
KISHI H, KONDO M, ARAI K, WATANABE G, TAYA K. Involvement of Ovarian Inhibin and Steroid Hormones in the Regulation of Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH) Secretion during Pseudopregnancy in the Rat. J Reprod Dev 1997. [DOI: 10.1262/jrd.43.243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Hisashi KISHI
- Laboratory of Veterinary Physiology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183, Japan
| | - Masahiro KONDO
- Laboratory of Veterinary Physiology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183, Japan
| | - Koji ARAI
- Laboratory of Veterinary Physiology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183, Japan
| | - Gen WATANABE
- Laboratory of Veterinary Physiology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183, Japan
| | - Kazuyoshi TAYA
- Laboratory of Veterinary Physiology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183, Japan
| |
Collapse
|
16
|
KISHI H, KONDOH M, NAGAMINE N, SHI F, WATANABE G, TAYA K. Roles of the Basal Level of LH and FSH in the Regulation of Follicular Development during Pseudopregnancy in the Rat. J Reprod Dev 1997. [DOI: 10.1262/jrd.43.279] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Hisashi KISHI
- Laboratory of Veterinary Physiology, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183, Japan
| | - Masahiro KONDOH
- Laboratory of Veterinary Physiology, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183, Japan
| | - Natsuko NAGAMINE
- Laboratory of Veterinary Physiology, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183, Japan
| | - Fagxiong SHI
- Laboratory of Veterinary Physiology, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183, Japan
| | - Gen WATANABE
- Laboratory of Veterinary Physiology, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183, Japan
| | - Kazuyoshi TAYA
- Laboratory of Veterinary Physiology, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183, Japan
| |
Collapse
|
17
|
Tobias JH, Chambers TJ, Gallagher A. Effect of administration and subsequent cessation of buserelin on cancellous bone of female rats. J Bone Miner Res 1994; 9:1919-25. [PMID: 7872057 DOI: 10.1002/jbmr.5650091211] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Although hormone replacement therapy is effective in preventing postmenopausal bone loss, it fails to cause a return of bone mass to normal in patients with established osteoporosis. Similarly, in the ovariectomized rat, estrogen administration protects the skeleton from bone loss but fails to reverse this once it has occurred. However, physiologically produced sex steroids may, in contrast to conventional methods of sex steroid administration, be capable of restoring bone mass in osteopenic states. To investigate this question, we analyzed the effect of treatment with the LHRH agonist buserelin for varying durations, and subsequent cessation thereof, on histomorphometric indices of rat cancellous bone. Female rats 13 weeks old were given daily SC injections of vehicle or buserelin as follows: vehicle days 1-90; vehicle days 1-150; vehicle days 1-60, buserelin days 61-90; vehicle days 1-60, buserelin days 61-90, vehicle days 91-150; vehicle days 1-30, buserelin days 31-90; vehicle days 1-30, buserelin days 31-90, vehicle days 91-150; buserelin days 1-90; buserelin days 1-90, vehicle days 91-150. At the end of the treatment period, animals were killed, tibiae removed, and histomorphometric indices assessed at the secondary spongiosa of the proximal metaphysis. Analysis of vaginal smears confirmed that buserelin rapidly suppressed ovulation, which quickly returned once treatment was stopped. We found that administration of buserelin for 30, 60, or 90 days reduced cancellous bone volume because of a reduction in both the number and thickness of trabeculae.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- J H Tobias
- Department of Histopathology, St. George's Hospital Medical School, London, England
| | | | | |
Collapse
|
18
|
Nagano M, Kelly P. Tissue distribution and regulation of rat prolactin receptor gene expression. Quantitative analysis by polymerase chain reaction. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)36838-2] [Citation(s) in RCA: 177] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
|
19
|
Greenberg C, Kukreja SC, Bowser EN, Hargis GK, Henderson WJ, Williams GA. Parathyroid hormone secretion: effect of estradiol and progesterone. Metabolism 1987; 36:151-4. [PMID: 3807787 DOI: 10.1016/0026-0495(87)90009-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Previous studies have shown that estrogen therapy in postmenopausal women results in an increase in serum immunoreactive parathyroid hormone (iPTH) levels. It has been assumed that this effect of estrogen on PTH secretion is indirect, being mediated via mild hypocalcemia resulting from an inhibition of bone resorption. We evaluated the direct effect of 17 beta-estradiol (E2) and of progesterone (Prog) on secretion of PTH from bovine parathyroid tissue in vitro. Both E2 and Prog caused a significant stimulation of PTH secretion within one hour, which was progressive for the three-hour observation period. The responses were dose-related from 10(-7) to 5 X 10(-10) mol/L. There was no PTH response to 10(-7) mol/L alpha-E2, 3-methoxy estriol, estrone, testosterone, or 20-alpha-hydroxy progesterone, indicating specificity of the responses to E2 and Prog. There was a minimal PTH secretory response to 10(-6) mol/L cortisol and 10(-6) mol/L estrone. The E2 receptor antagonist tamoxifen did not inhibit the E2 effect on PTH secretion. This observation plus the rapid PTH response suggests that this hormonal effect may not be via the conventional intracellular E2 receptor. Therefore, E2 and Prog can stimulate PTH secretion by rapid, direct, and specific effects on parathyroid cells. These gonadal hormones may, therefore, be important in calcium homeostasis via their direct stimulatory effect on PTH secretion.
Collapse
|
20
|
Taya K, Greenwald GS. Postovulatory steroidogenesis after PMS-induced ovulation in immature female rats. THE AMERICAN JOURNAL OF PHYSIOLOGY 1981; 241:E221-5. [PMID: 6792929 DOI: 10.1152/ajpendo.1981.241.3.e221] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Thirty-day-old rats given a single subcutaneous injection of 5 IU pregnant mare serum gonadotropin (PMS) at 0900 h ovulated on the morning of day 33 (= estrus). However, the second ovulation did not occur until 9.4 days later. To determine the mechanism responsible for the delay in the second ovulation, in vivo and in vitro determinations of steroid and peptide hormones were compared between PMS-primed immature rats and adult cyclic rats. In PMS-primed rats, the corpora lutea (CL) produced progesterone for 2 days longer (until day 36) than the CL of the adult rat. Serum levels of 20 alpha-dihydroprogesterone, testosterone, and estradiol in PMS-primed rats were significantly lower than the corresponding values in adult rats. Serum LH was consistently lower in the PMS-primed rats. An increase in serum FSH occurred on days 36-37, which may be responsible for maturation of the follicles destined to ovulate at the second ovulation. On day 37, the nonluteal ovary of the PMS-primed rats also began to produce in vitro appreciable amounts of testosterone and estradiol. These findings suggest that the greater levels of prolactin and/or low levels of luteinizing hormone during estrus in PMS-primed rats may be responsible for the prolonged secretion of progesterone by the CL. This in turn inhibits follicular maturation, indirectly by lowering serum LH, which is reflected in reduced ability of the follicles in vitro to produce testosterone and estradiol until the CL regress.
Collapse
|