1
|
McCartney CR, Campbell RE, Marshall JC, Moenter SM. The role of gonadotropin-releasing hormone neurons in polycystic ovary syndrome. J Neuroendocrinol 2022; 34:e13093. [PMID: 35083794 PMCID: PMC9232905 DOI: 10.1111/jne.13093] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 12/21/2021] [Accepted: 01/11/2022] [Indexed: 01/28/2023]
Abstract
Given the critical central role of gonadotropin-releasing hormone (GnRH) neurons in fertility, it is not surprising that the GnRH neural network is implicated in the pathology of polycystic ovary syndrome (PCOS), the most common cause of anovulatory infertility. Although many symptoms of PCOS relate most proximately to ovarian dysfunction, the central reproductive neuroendocrine system ultimately drives ovarian function through its regulation of anterior pituitary gonadotropin release. The typical cyclical changes in frequency of GnRH release are often absent in women with PCOS, resulting in a persistent high-frequency drive promoting gonadotropin changes (i.e., relatively high luteinizing hormone and relatively low follicle-stimulating hormone concentrations) that contribute to ovarian hyperandrogenemia and ovulatory dysfunction. However, the specific mechanisms underpinning GnRH neuron dysfunction in PCOS remain unclear. Here, we summarize several preclinical and clinical studies that explore the causes of aberrant GnRH secretion in PCOS and the role of disordered GnRH secretion in PCOS pathophysiology.
Collapse
Affiliation(s)
- Christopher R. McCartney
- Center for Research in Reproduction and Department of MedicineUniversity of Virginia School of MedicineCharlottesvilleVAUSA
| | - Rebecca E. Campbell
- Centre for Neuroendocrinology and Department of PhysiologySchool of Biomedical SciencesUniversity of OtagoDunedinNew Zealand
| | - John C. Marshall
- Center for Research in Reproduction and Department of MedicineUniversity of Virginia School of MedicineCharlottesvilleVAUSA
| | - Suzanne M. Moenter
- Departments of Molecular & Integrative PhysiologyInternal MedicineObstetrics and GynecologyUniversity of MichiganAnn ArborMIUSA
| |
Collapse
|
2
|
Goodman RL, Herbison AE, Lehman MN, Navarro VM. Neuroendocrine control of gonadotropin-releasing hormone: Pulsatile and surge modes of secretion. J Neuroendocrinol 2022; 34:e13094. [PMID: 35107859 PMCID: PMC9948945 DOI: 10.1111/jne.13094] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 01/12/2022] [Accepted: 01/14/2022] [Indexed: 11/28/2022]
Abstract
The concept that different systems control episodic and surge secretion of gonadotropin-releasing hormone (GnRH) was well established by the time that GnRH was identified and formed the framework for studies of the physiological roles of GnRH, and later kisspeptin. Here, we focus on recent studies identifying the neural mechanisms underlying these two modes of secretion, with an emphasis on their core components. There is now compelling data that kisspeptin neurons in the arcuate nucleus that also contain neurokinin B (NKB) and dynorphin (i.e., KNDy cells) and their projections to GnRH dendrons constitute the GnRH pulse generator in mice and rats. There is also strong evidence for a similar role for KNDy neurons in sheep and goats, and weaker data in monkeys and humans. However, whether KNDy neurons act on GnRH dendrons and/or GnRH soma and dendrites that are found in the mediobasal hypothalamus (MBH) of these species remains unclear. The core components of the GnRH/luteinising hormone surge consist of an endocrine signal that initiates the process and a neural trigger that drives GnRH secretion during the surge. In all spontaneous ovulators, the core endocrine signal is a rise in estradiol secretion from the maturing follicle(s), with the site of estrogen positive feedback being the rostral periventricular kisspeptin neurons in rodents and neurons in the MBH of sheep and primates. There is considerable species variations in the neural trigger, with three major classes. First, in reflex ovulators, this trigger is initiated by coitus and carried to the hypothalamus by neural or vascular pathways. Second, in rodents, there is a time of day signal that originates in the suprachiasmatic nucleus and activates rostral periventricular kisspeptin neurons and GnRH soma and dendrites. Finally, in sheep nitric oxide-producing neurons in the ventromedial nucleus, KNDy neurons and rostral kisspeptin neurons all appear to participate in driving GnRH release during the surge.
Collapse
Affiliation(s)
- Robert L. Goodman
- Department of Physiology and Pharmacology, West Virginia University, Morgantown, WV, USA
| | - Allan E. Herbison
- Department of Physiology Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Michael N. Lehman
- Brain Health Research Institute, Kent State University, Kent, OH, USA
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Victor M. Navarro
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women’s Hospital, Harvard Medical School and Department of Medicine, Boston, MA, USA
| |
Collapse
|
3
|
Zhang Q, Guo XM, Li Y. Implantation rates subsequent to the transfer of embryos produced at different phases during double stimulation of poor ovarian responders. Reprod Fertil Dev 2018; 29:1178-1183. [PMID: 27166216 DOI: 10.1071/rd16020] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 03/17/2016] [Indexed: 11/23/2022] Open
Abstract
To compare the implantation capacity of embryos obtained at different phases of double stimulation (DS) of poor ovarian responders, 153 DS cycles were analysed retrospectively. As part of the DS protocol, antral follicles were stimulated continuously during both the follicular and luteal phases. Fresh embryos obtained in both phases were cryopreserved and transferred in the next artificial cycle. The mean number of oocytes retrieved, MII oocytes and zygotes with two pronuclei was significantly higher for collections during luteal-phase stimulation. Furthermore, the dose of exogenous gonadotropin administered was higher during the luteal phase. The rate of clinical pregnancy and embryo implantation increased progressively from pure follicular phase embryos to mixed embryos to pure luteal phase embryos. Embryos produced during the luteal phase resulted in higher implantation rates.
Collapse
Affiliation(s)
- Qiong Zhang
- Center for Reproductive Medicine, Xiang-Ya Hospital, Central South University, 87th Xiangya Road, Changsha, Hunan, 410000, China
| | - Xiaoyue M Guo
- Yale University School of Medicine, New Haven, CT, USA
| | - Yanping Li
- Center for Reproductive Medicine, Xiang-Ya Hospital, Central South University, 87th Xiangya Road, Changsha, Hunan, 410000, China
| |
Collapse
|
4
|
Kim SH, Burt Solorzano CM, McCartney CR. Progesterone administration does not acutely alter LH pulse secretion in the mid-follicular phase in women. Physiol Rep 2018; 6:e13680. [PMID: 29696832 PMCID: PMC5917047 DOI: 10.14814/phy2.13680] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 03/13/2018] [Accepted: 03/16/2018] [Indexed: 11/24/2022] Open
Abstract
It remains unclear how rapidly progesterone suppresses luteinizing hormone (LH) pulse frequency in women. Previous studies suggested that progesterone markedly increases LH pulse amplitude but does not slow LH pulse frequency within 10 h in estradiol‐pretreated women studied during the late follicular phase. However, this experimental paradigm may be a model of preovulatory physiology, and progesterone may have different effects at other times of the cycle. We studied regularly cycling, nonobese women without hyperandrogenism to assess the acute effect of progesterone during the midfollicular phase and in the absence of estradiol pretreatment. The study involved two admissions in separate cycles (cycle days 5–9). For each admission, either oral micronized progesterone (100 mg) or placebo was administered at 0900 h in a randomized, double‐blind fashion. Frequent blood sampling was performed between 0900 and 1900 h to define 10‐h LH pulsatility. Treatment crossover (placebo exchanged for progesterone and vice versa) occurred in a subsequent cycle. After an interim futility analysis, the study was halted after 7 women completed study. Mean progesterone concentrations after placebo and progesterone administration were 0.5 ± 0.1 (mean ± SD) and 6.7 ± 1.6 ng/mL, respectively. Compared to placebo, progesterone was not associated with a significant difference in 10‐h LH pulse frequency (0.79 ± 0.35 vs. 0.77 ± 0.28 pulses/h, P = 1.0) or amplitude (3.6 ± 2.8 vs. 4.3 ± 2.8 IU/L, P = 0.30). This study suggests that LH pulse frequency is not rapidly influenced by progesterone administration during the midfollicular phase.
Collapse
Affiliation(s)
- Su Hee Kim
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia.,Center for Research in Reproduction, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Christine M Burt Solorzano
- Center for Research in Reproduction, University of Virginia School of Medicine, Charlottesville, Virginia.,Division of Endocrinology and Metabolism, Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Christopher R McCartney
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia.,Center for Research in Reproduction, University of Virginia School of Medicine, Charlottesville, Virginia
| |
Collapse
|
5
|
Kim SH, Lundgren JA, Bhabhra R, Collins JS, Patrie JT, Burt Solorzano CM, Marshall JC, McCartney CR. Progesterone-Mediated Inhibition of the GnRH Pulse Generator: Differential Sensitivity as a Function of Sleep Status. J Clin Endocrinol Metab 2018; 103:1112-1121. [PMID: 29300925 PMCID: PMC6283412 DOI: 10.1210/jc.2017-02299] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 12/21/2017] [Indexed: 11/19/2022]
Abstract
CONTEXT During normal, early puberty, luteinizing hormone (LH) pulse frequency is low while awake but increases during sleep. Mechanisms underlying such changes are unclear, but a small study in early pubertal girls suggested that differential wake-sleep sensitivity to progesterone negative feedback plays a role. OBJECTIVE To test the hypothesis that progesterone acutely reduces waking LH pulse frequency more than sleep-associated pulse frequency in late pubertal girls. DESIGN Randomized, placebo-controlled, double-blinded crossover study. SETTING Academic clinical research unit. PARTICIPANTS Eleven normal, postmenarcheal girls, ages 12 to 15 years. INTERVENTION Subjects completed two 18-hour admissions in separate menstrual cycles (cycle days 6 to 11). Frequent blood sampling for LH assessment was performed at 1800 to 1200 hours; sleep was encouraged at 2300 to 0700 hours. Either oral micronized progesterone (0.8 mg/kg/dose) or placebo was given at 0700, 1500, 2300, and 0700 hours, before and during the first admission. A second admission, performed at least 2 months later, was identical to the first except that placebo was exchanged for progesterone or vice versa (treatment crossover). MAIN OUTCOME MEASURES LH pulse frequency during waking and sleeping hours. RESULTS Progesterone reduced waking LH pulse frequency by 26% (P = 0.019), with no change observed during sleep (P = 0.314). The interaction between treatment condition (progesterone vs placebo) and sleep status (wake vs sleep) was highly significant (P = 0.007). CONCLUSIONS In late pubertal girls, progesterone acutely reduced waking LH pulse frequency more than sleep-associated pulse frequency. Differential wake-sleep sensitivity to progesterone negative feedback may direct sleep-wake LH pulse frequency changes across puberty.
Collapse
Affiliation(s)
- Su Hee Kim
- Center for Research in Reproduction, University of Virginia School of Medicine, Charlottesville, Virginia
- Division of Endocrinology, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Jessica A Lundgren
- Center for Research in Reproduction, University of Virginia School of Medicine, Charlottesville, Virginia
- Division of Endocrinology, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Ruchi Bhabhra
- Center for Research in Reproduction, University of Virginia School of Medicine, Charlottesville, Virginia
- Division of Endocrinology, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Jessicah S Collins
- Center for Research in Reproduction, University of Virginia School of Medicine, Charlottesville, Virginia
- Division of Endocrinology, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia
| | - James T Patrie
- Department of Public Health Sciences, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Christine M Burt Solorzano
- Center for Research in Reproduction, University of Virginia School of Medicine, Charlottesville, Virginia
- Division of Endocrinology, Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia
| | - John C Marshall
- Center for Research in Reproduction, University of Virginia School of Medicine, Charlottesville, Virginia
- Division of Endocrinology, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Christopher R McCartney
- Center for Research in Reproduction, University of Virginia School of Medicine, Charlottesville, Virginia
- Division of Endocrinology, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia
- Correspondence and Reprint Requests: Christopher R. McCartney, MD, Center for Research in Reproduction, University of Virginia Health System, Box 800391, Charlottesville, Virginia 22908. E-mail:
| |
Collapse
|
6
|
Van Vugt DA, Krzemien A, Roy BN, Fletcher WA, Foster W, Lundahl S, Marcus SL, Reid RL. Photodynamic Endometrial Ablation in the Nonhuman Primate. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/107155760000700208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Dean A. Van Vugt
- Departments of Obstetrics and Gynecology, Physiology, and Pathology, Queen's University, Kingston, Ontario, Canada; Health Canada, Ottawa, Ontario, Canada; and DUSA Pharmaceuticals Inc., Valhalla, New York
| | | | | | | | | | | | | | - Robert L. Reid
- Departments of Obstetrics and Gynecology, Physiology, and Pathology, Queen's University, Kingston, Ontario, Canada; Health Canada, Ottawa, Ontario, Canada; and DUSA Pharmaceuticals Inc., Valhalla, New York
| |
Collapse
|
7
|
Alçin E, Sahu A, Ramaswamy S, Hutz E, Keen K, Terasawa E, Bethea C, Plant T. Ovarian regulation of kisspeptin neurones in the arcuate nucleus of the rhesus monkey (macaca mulatta). J Neuroendocrinol 2013; 25:488-96. [PMID: 23331967 PMCID: PMC3928808 DOI: 10.1111/jne.12025] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 01/03/2013] [Accepted: 01/10/2013] [Indexed: 11/28/2022]
Abstract
Tonic gonadotrophin secretion throughout the menstrual cycle is regulated by the negative-feedback actions of ovarian oestradiol (E₂) and progesterone. Although kisspeptin neurones in the arcuate nucleus (ARC) of the hypothalamus appear to play a major role in mediating these feedback actions of the steroids in nonprimate species, this issue has been less well studied in the monkey. In the present study, we used immunohistochemistry and in situ hybridisation to examine kisspeptin and KISS1 expression, respectively, in the mediobasal hypothalamus (MBH) of adult ovariectomised (OVX) rhesus monkeys. We also examined kisspeptin expression in the MBH of ovarian intact females, and the effect of E₂, progesterone and E₂ + progesterone replacement on KISS1 expression in OVX animals. Kisspeptin or KISS1 expressing neurones and pronounced kisspeptin fibres were readily identified throughout the ARC of ovariectomised monkeys but, on the other hand, in intact animals, kisspeptin cell bodies were small in size and number and only fine fibres were observed. Replacement of OVX monkeys with physiological levels of E₂, either alone or with luteal phase levels of progesterone, abolished KISS1 expression in the ARC. Interestingly, progesterone replacement alone for 14 days also resulted in a significant down-regulation of KISS1 expression. These findings support the view that, in primates, as in rodents and sheep, kisspeptin signalling in ARC neurones appears to play an important role in mediating the negative-feedback action of E₂ on gonadotrophin secretion, and also indicate the need to study further their regulation by progesterone.
Collapse
Affiliation(s)
- E. Alçin
- University of Pittsburgh, Department of Obstetrics, Gynecology and Reproductive Sciences, Magee-Womens Research Institute, Pittsburgh, PA 15213 USA
| | - A. Sahu
- University of Pittsburgh, Department of Obstetrics, Gynecology and Reproductive Sciences, Magee-Womens Research Institute, Pittsburgh, PA 15213 USA
| | - S. Ramaswamy
- University of Pittsburgh, Department of Obstetrics, Gynecology and Reproductive Sciences, Magee-Womens Research Institute, Pittsburgh, PA 15213 USA
| | - E.D. Hutz
- Wisconsin National Primate Research Center, University of Wisconsin, Madison, WI 53715 USA
| | - K.L. Keen
- Wisconsin National Primate Research Center, University of Wisconsin, Madison, WI 53715 USA
| | - E. Terasawa
- Wisconsin National Primate Research Center, University of Wisconsin, Madison, WI 53715 USA
- Department of Pediatrics, University of Wisconsin, Madison, WI 53715 USA
| | - C.L. Bethea
- Division of Reproductive Sciences and Neuroscience, Oregon National Primate Research Center, Beaverton, OR 97006 USA
| | - T.M. Plant
- University of Pittsburgh, Department of Obstetrics, Gynecology and Reproductive Sciences, Magee-Womens Research Institute, Pittsburgh, PA 15213 USA
- Corresponding author: Dr. Tony M. Plant, University of Pittsburgh, Dept. OB/GYN & Reprod Sci, Magee-Womens Research Institute, 204 Craft Avenue, Pittsburgh, PA 15213,
| |
Collapse
|
8
|
Zarazaga LA, Gatica MC, Celi I, Guzmán JL, Malpaux B. Exogenous melatonin after a treatment of artificial long days is able to increase LH secretion during seasonal anoestrus in Payoya goats. JOURNAL OF APPLIED ANIMAL RESEARCH 2013. [DOI: 10.1080/09712119.2012.738226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
9
|
Zarazaga LA, Celi I, Guzmán JL, Malpaux B. The effect of nutrition on the neural mechanisms potentially involved in melatonin-stimulated LH secretion in female Mediterranean goats. J Endocrinol 2011; 211:263-72. [PMID: 21903864 DOI: 10.1530/joe-11-0225] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This research examines which neural mechanisms among the endogenous opioid, dopaminergic, serotonergic and excitatory amino acid systems are involved in the stimulation of LH secretion by melatonin implantation and their modulation by nutritional level. Female goats were distributed to two experimental groups that received either 1.1 (group H; n=24) or 0.7 (group L; n=24) times their nutritional maintenance requirements. Half of each group was implanted with melatonin after a long-day period. Plasma LH concentrations were measured twice per week. The effects of i.v. injections of naloxone, pimozide, cyproheptadine and N-methyl-d,l-aspartate (NMDA) on LH secretion were assessed the day before melatonin implantation and again on days 30 and 45. The functioning of all but the dopaminergic systems was clearly modified by the level of nutrition, melatonin implantation and time elapsed since implantation. Thirty days after implantation, naloxone increased LH concentrations irrespective of the level of nutrition (P<0.05), similar to NMDA in the melatonin-implanted H goats (HM; P<0.01). On day 45, naloxone increased LH concentrations in the HM animals (P<0.05), similar to cyproheptadine in both the non-implanted H (HC) and the HM animals (P<0.01). Finally, at 45 days, NMDA increased the LH concentration in all subgroups (P<0.01). These results provide evidence that the effects of different neural systems on LH secretion are modified by nutritional level and melatonin implantation. Endogenous opioids seem to be most strongly involved in the inhibition of LH secretion on days 30 and 45 after melatonin implantation. However, the serotonergic mechanism appears to be most influenced by nutritional level.
Collapse
Affiliation(s)
- Luis A Zarazaga
- Department of Agroforestry Sciences, University of Huelva, Carretera de Palos de la Frontera s/n, Palos de la Frontera, 21819 Huelva, Spain.
| | | | | | | |
Collapse
|
10
|
Caserta D, Lisi F, Marci R, Ciardo F, Fazi A, Lisi R, Moscarini M. Does supplementation with recombinant luteinizing hormone prevent ovarian hyperstimulation syndrome in down regulated patients undergoing recombinant follicle stimulating hormone multiple follicular stimulation for IVF/ET and reduces cancellation rate for high risk of hyperstimulation? Gynecol Endocrinol 2011; 27:862-6. [PMID: 21391759 DOI: 10.3109/09513590.2010.544133] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Aim of this study was to assess the efficacy of recombinant luteinizing hormone (rLH) supplementation in late follicular phase in multiple follicular stimulation with recombinant follicle stimulating hormone (rFSH) in Triptoreline down-regulated patients undergoing IVF, on preventing clinical OHSS and cycles cancellation for OHSS risk. Nine hundred ninety-nine patients aged ≤ 40 with basal FSH ≤ 12 mUI/Ml were down-regulated before starting rFSH stimulation for oocytes recovery. Patients were allocated in two groups: (A) (501 patients) treated with 150 IU of rFSH eventually adjusting rFSH dosage day 7 of stimulation until recombinant human chorionic gonadotropin (rhCG) administration, (B) (498 patients) treated with 150 IU of rFSH and 75 IU of rLH since day 7 of stimulation until rhCG administration and adjusting rFSH at the same day. E2 the day of rhCG was higher in group B (p < 0.0001); number of cycles cancelled in group A (42/8.3%) for risk of ovarian hyperstimulation syndrome (OHSS) was higher than group B (12/2.4%) (p < 0.000001). We observed an increase in pregnancies in group B compared with group A (16.8% vs 11.9%) (p < 0.05) and we observed also a larger number of clinical OHSS in group A than in group B (p < 0.05).
Collapse
Affiliation(s)
- Donatella Caserta
- Department of Woman Health and Territory's Medicine, University of Rome Sapienza, S. Andrea Hospital, Rome, Italy.
| | | | | | | | | | | | | |
Collapse
|
11
|
Zarazaga L, Celi I, Guzmán J, Malpaux B. The response of luteinizing hormone secretion to photoperiod is modified by the level of nutrition in female Mediterranean goats. Anim Reprod Sci 2011; 126:83-90. [DOI: 10.1016/j.anireprosci.2011.04.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2010] [Revised: 04/13/2011] [Accepted: 04/26/2011] [Indexed: 10/18/2022]
|
12
|
Zarazaga LA, Celi I, Guzmán JL, Malpaux B. The Role of Nutrition in the Regulation of Luteinizing Hormone Secretion by the Opioidergic, Dopaminergic, and Serotonergic Systems in Female Mediterranean Goats1. Biol Reprod 2011; 84:447-54. [DOI: 10.1095/biolreprod.110.086520] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
|
13
|
Effect of melatonin implants on sexual activity in Mediterranean goat females without separation from males. Theriogenology 2009; 72:910-8. [DOI: 10.1016/j.theriogenology.2009.05.020] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2009] [Revised: 04/29/2009] [Accepted: 05/23/2009] [Indexed: 10/20/2022]
|
14
|
Zarazaga LA, Guzmán JL, Domínguez C, Pérez MC, Prieto R. Effect of plane of nutrition on seasonality of reproduction in Spanish Payoya goats. Anim Reprod Sci 2005; 87:253-67. [PMID: 15911175 DOI: 10.1016/j.anireprosci.2004.11.004] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2004] [Revised: 10/12/2004] [Accepted: 11/09/2004] [Indexed: 11/25/2022]
Abstract
The aim of this study was to determine if there is a seasonal pattern of sexual activity in female Payoya goats and if this seasonality could be modulated by nutrition. During the experimental period of 20 months, 43 non-pregnant adults goats were penned under natural photoperiod at latitude 37 degrees 15'N. At the onset of the experiment, the animals were allocated to three experimental groups differing in the level of nutrition and whether the animals were entire or ovariectomized does. The high nutrition group (H, n = 16 entire does) receiving 1.5 times maintenance requirements. The low nutrition group (L, n = 16 entire does) and an ovariectomized and oestradiol treated group (OVX, n = 11 ovariectomized does) received a diet supporting their maintenance requirements. The groups were balanced for live weight (LW) and body condition score (BCS) at the beginning of the study. In entire goats, oestrus was tested daily using aproned males, ovulation rate was assessed by laparoscopy 7 days after identification of oestrus and plasma samples were obtained twice per week for progesterone assay. OVX goats were isolated from the other groups and bucks, plasma samples were assayed twice per week for LH and there were four intensive sampling periods during the year to determine LH pulsatility. LW and BCS were recorded for all animals once a week. A clear circannual cycle in live weight change was observed in all experimental groups, being relatively stable or slightly decreasing in summer and autumn and increasing during winter and spring. The effect of exposure to high (H) rather than low (L) nutrition was to cause earlier onset of ovarian activity (5 versus 17 August; P < 0.05), and expression of oestrous (16 August versus 2 September; P < 0.01) and later cessation of reproductive activity (ovulation 11 February versus 17 January; P < 0.01). Consequently, seasonal anoestrus was 32 days shorter in does on the higher plane of nutrition (P < 0.01). The seasonality of reproductive activity was confirmed in the OVX does, with reduced LH concentrations during spring and summer, and increased LH concentrations in autumn and winter. There was no effect of nutrition on ovulation rate. These results demonstrate that the female Payoya goat exhibits marked reproductive seasonality which is modulated by nutrition but possibly not ovulation rate.
Collapse
Affiliation(s)
- L A Zarazaga
- Departamento de Ciencias Agroforestales, Universidad de Huelva, Carretera de Palos de la Frontera s/n, 21819 Palos de la Frontera, Huelva, Spain.
| | | | | | | | | |
Collapse
|
15
|
Byers MJ, Zangl A, Phernetton TM, Lopez G, Chen DB, Magness RR. Endothelial vasodilator production by ovine uterine and systemic arteries: ovarian steroid and pregnancy control of ERalpha and ERbeta levels. J Physiol 2005; 565:85-99. [PMID: 15774511 PMCID: PMC1464491 DOI: 10.1113/jphysiol.2005.085753] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Pregnancy and the follicular phase are physiological states of elevated oestrogen levels and rises in uterine blood flow (UBF). The dramatic increase in utero-placental blood flow during gestation is required for normal fetal growth and development. Oestrogen exerts its vasodilatory effect by binding to its specific oestrogen receptors (ER) in target cells, resulting in increased expression and activity of endothelial nitric oxide synthase (eNOS) to relax vascular smooth muscle (VSM). However, the regulation of endothelial versus VSM ERalpha and ERbeta expression in uterine arteries (UAs) during the ovarian cycle, pregnancy and with exogenous hormone replacement therapy (HRT) are currently unknown. ER mRNA and protein localization was determined by in situ hybridization (ISH) using 35S-labelled riboprobes and immunohistochemistry (IHC), respectively. UA endothelial (UAendo), UA VSM, omental artery endothelium (OA endo), and OA VSM proteins were isolated and ERalpha and ERbeta protein expression was determined by Western analysis. We observed by ISH and IHC that ERalpha and ERbeta mRNA and protein were localized in both UAendo and UA VSM. Immunoblot data demonstrated ovarian hormone specific regulation of ERalpha and ERbeta protein in UAendo and UA VSM. Compared to luteal phase sheep, both ERalpha and ERbeta levels in UAendo were elevated in follicular phase sheep. Whereas ERbeta was elevated by pregnancy in UAendo and UA VSM, ERalpha was not appreciably altered. eNOS was increased in UAendo from follicular and pregnant sheep. Ovariectomized ewes (OVEX) had substantially reduced UAendo ERbeta, but not UAendo ERalpha or OAendo ERalpha and ERbeta. In contrast, OVEX increased UA VSM ERalpha and ERbeta and decreased OA VSM ERalpha and ERbeta. Treatment with oestradiol-17beta (E2beta), but not progesterone or their combination, increased UAendo ERalpha levels. The reduced ERbeta in UAendo from OVEX ewes was reversed by E(2)beta and progesterone treatment. While ERalpha and eNOS were not elevated in any other reproductive or non-reproductive endothelia tested, ERbeta was augmented by pregnancy in uterine, mammary, placenta, and coronary artery endothelia. ERalpha and ERbeta mRNA and protein are expressed in UA endothelium with expression levels depending on the endocrine status of the animal, indicating UA endothelium is a target for oestrogen action in vivo, and that the two receptors appear to be differentially regulated in a spatial and temporal fashion with regard to the reproductive status or HRT.
Collapse
Affiliation(s)
- Michael J Byers
- Perinatal Research Laboratories, University of Wisconsin-Madison Medical School, Department of Obstetrics and Gynecology, Atrium-B Meriter Hospital/Park , Madison, WI 53715, USA
| | | | | | | | | | | |
Collapse
|
16
|
Abstract
During the follicular phase of the primate menstrual cycle, a single follicle usually matures to the preovulatory stage and releases its oocyte for fertilization and the potential establishment of pregnancy. In assisted reproductive technology procedures, it is desirable to override the natural process of follicle selection to produce many oocytes that are capable of being fertilized and undergoing normal embryo development. The goal of this chapter is to summarize the current views regarding the natural process of follicle selection in primates and to discuss how this process may be amplified to produce a greater number of oocytes.
Collapse
Affiliation(s)
- Anthony J Zeleznik
- Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
| |
Collapse
|
17
|
Jansen HT, Cutter C, Hardy S, Lehman MN, Goodman RL. Seasonal plasticity within the gonadotropin-releasing hormone (GnRH) system of the ewe: changes in identified GnRH inputs and glial association. Endocrinology 2003; 144:3663-76. [PMID: 12865349 DOI: 10.1210/en.2002-0188] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The annual reproductive cycle in sheep may reflect a functional remodeling within the GnRH system. Specifically, changes in total synaptic input and association with the polysialylated form of neural cell adhesion molecule have been observed. Whether seasonal changes in a specific subset(s) of GnRH inputs occur or whether glial cells specifically play a role in this remodeling is not clear. We therefore examined GnRH neurons of breeding season (BS) and nonbreeding season (anestrus) ewes and tested the hypotheses that specific (i.e. gamma-aminobutyric acid, catecholamine, neuropeptide Y, or beta-endorphin) inputs to GnRH neurons change seasonally, and concomitant with any changes in neural inputs is a change in glial apposition. Using triple-label immunofluorescent visualization of GnRH, glial acidic fibrillary protein and neuromodulator/neural terminal markers combined with confocal microscopy and optical sectioning techniques, we confirmed that total numbers of neural inputs to GnRH neurons vary with season and demonstrated that specific inputs contribute to these overall changes. Specifically, neuropeptide Y and gamma-aminobutyric acid inputs to GnRH neurons increased during BS and beta-endorphin inputs were greater during either anestrus (GnRH somas) or BS (GnRH dendrites). Associated with the changes in GnRH inputs were seasonal changes in glial apposition, glial acidic fibrillary protein density, and the thickness of glial fibrils. These findings are interpreted to suggest an increase in net stimulatory inputs to GnRH neurons during the BS contributes to the seasonal changes in GnRH neurosecretion and that this increased innervation is perhaps stabilized by glial processes.
Collapse
Affiliation(s)
- Heiko T Jansen
- Department of Veterinary and Comparative Anatomy, Washington State University College of Veterinary Medicine, Pullman, Washington 99164-6520, USA.
| | | | | | | | | |
Collapse
|
18
|
Chemineau P, Daveau A, Pelletier J, Malpaux B, Karsch FJ, Viguié C. Changes in the 5-HT2A receptor system in the pre-mammillary hypothalamus of the ewe are related to regulation of LH pulsatile secretion by an endogenous circannual rhythm. BMC Neurosci 2003; 4:1. [PMID: 12553884 PMCID: PMC149365 DOI: 10.1186/1471-2202-4-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2002] [Accepted: 01/28/2003] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND We wanted to determine if changes in the expression of serotonin 2A receptor (5HT2A receptor) gene in the premammillary hypothalamus are associated with changes in reproductive neuroendocrine status. Thus, we compared 2 groups of ovariectomized-estradiol-treated ewes that expressed high vs low LH pulsatility in two different paradigms (2 groups per paradigm): (a) refractoriness (low LH secretion) or not (high LH secretion) to short days in pineal-intact Ile-de-France ewes (RSD) and (b) endogenous circannual rhythm (ECR) in free-running pinealectomized Suffolk ewes in the active or inactive stage of their reproductive rhythm. RESULTS In RSD ewes, density of 5HT2A receptor mRNA (by in situ hybridization) was significantly higher in the high LH group (25.3 +/- 1.4 vs 21.4 +/- 1.5 grains/neuron, P < 0.05) and 3H-Ketanserin binding (a specific radioligand) of the median part of the premammillary hypothalamus tended to be higher in the high group (29.1 +/- 4.0 vs 24.6 +/- 4.2 fmol/mg tissu-equivalent; P < 0.10). In ECR ewes, density of 5HT2A receptor mRNA and 3H-Ketanserin binding were both significantly higher in the high LH group (20.8 +/- 1.6 vs 17.0 +/- 1.5 grains/neuron, P < 0.01, and 19.7 +/- 5.0 vs 7.4 +/- 3.4 fmol/mg tissu-equivalent; P < 0.05, respectively). CONCLUSIONS We conclude that these higher 5HT2A receptor gene expression and binding activity of 5HT2A receptor in the premammillary hypothalamus are associated with stimulation of LH pulsatility expressed before the development of refractoriness to short days and prior to the decline of reproductive neuroendocrine activity during expression of the endogenous circannual rhythm.
Collapse
Affiliation(s)
- Philippe Chemineau
- Equipe de Neuroendocrinologie et Maîtrise des Fonctions Saisonnières, Unité de Physiologie de la Reproduction et des Comportements, UMR INRA-CNRS- Univ. F. Rabelais, 37380 Nouzilly, France
| | - Agnès Daveau
- Equipe de Neuroendocrinologie et Maîtrise des Fonctions Saisonnières, Unité de Physiologie de la Reproduction et des Comportements, UMR INRA-CNRS- Univ. F. Rabelais, 37380 Nouzilly, France
| | - Jean Pelletier
- Equipe de Neuroendocrinologie et Maîtrise des Fonctions Saisonnières, Unité de Physiologie de la Reproduction et des Comportements, UMR INRA-CNRS- Univ. F. Rabelais, 37380 Nouzilly, France
| | - Benoît Malpaux
- Equipe de Neuroendocrinologie et Maîtrise des Fonctions Saisonnières, Unité de Physiologie de la Reproduction et des Comportements, UMR INRA-CNRS- Univ. F. Rabelais, 37380 Nouzilly, France
| | - Fred J Karsch
- Reproductive Sciences Program and Department of Physiology, University of Michigan, Ann Arbor, Michigan 48109-0404, USA
| | - Catherine Viguié
- Reproductive Sciences Program and Department of Physiology, University of Michigan, Ann Arbor, Michigan 48109-0404, USA
- Present adress: UMR 181, INRA-ENVT 23 chemin des Capelles, 31076 Toulouse, France
| |
Collapse
|
19
|
Abstract
During the follicular phase of humans and most nonhuman primates, a single preovulatory follicle usually matures each menstrual cycle. The observation that numerous preovulatory follicles may be stimulated to mature when exogenous gonadotropins are administered indicates that there must be a precise and highly reproducible mechanism by which only one of the many follicles capable of ovulating actually does so. The goal of this review is to summarize past and current research which indicates that follicle selection in primates is the result of an exquisitely sensitive interplay between gonadotropin secretion by the pituitary gland, steroid production by the ovary, and maturation-dependent alterations of the ovary's responsiveness to gonadotropins.
Collapse
Affiliation(s)
- A J Zeleznik
- Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA. zeleznik+@pitt.edu
| |
Collapse
|
20
|
|
21
|
Squires EL, Badzinski SL, Amann RP, McCue PM, Nett TM. Effects of altrenogest on total scrotal width, seminal characteristics, concentrations of LH and testosterone and sexual behavior of stallions. Theriogenology 1997; 48:313-28. [PMID: 16728130 DOI: 10.1016/s0093-691x(97)84078-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/1995] [Accepted: 03/06/1997] [Indexed: 11/26/2022]
Abstract
Twenty stallions (3 to 18 yr old) were used in a study between June 1993 and March 1994. The stallions were divided into 5 groups of 4 each, and, within groups, were randomly assigned to 1 of 4 treatments: 1) untreated controls; 2) once-a-day oral altrenogest (0.088 mg/kg BW) treatment for 150 d; 3) daily altrenogest treatment at the same dose for 240 d; and 4) daily oral altrenogest treatment for 240 d plus subcutaneous GnRH (80 microg) every 4 h from Days 151 to 240. Total scrotal width (TSW) was recorded and semen was collected and evaluated for gel free volume, concentration, sperm motility and sperm morphology. Sexual behavior (libido) was measured as times to first erection and ejaculation. Serum LH and testosterone (T) were measured at various periods throughout the study. Altrenogest decreased serum concentrations of LH and T, TSW, daily spermatozoa output (DSO), the percentage of normal spermatozoa and libido. There was a significant decrease in sperm motility in the Alt-240 and Alt-240+GnRH group, but not the ALT-150 group. The suppression appeared to be partially reversible because DSO, TSW and serum concentrations of LH increased after cessation of progestin treatment. Administration of GnRH during altrenogest treatment resulted in increased (P < 0.05) TSW, DSO and serum concentrations of LH but did not alter sperm morphology or behavior. In summary, the suppressive effects of altrenogest were apparently mediated primarily through a negative feedback inhibition of LH secretion.
Collapse
Affiliation(s)
- E L Squires
- Animal Reproduction and Biotechnology Laboratory Colorado State University, Fort Collins, CO 80523, USA
| | | | | | | | | |
Collapse
|
22
|
Sánchez F, Carretero J, Rubio M, Riesco JM, Vázquez R. Morphometric analysis of the hypoactivity of FSH-immunoreactive cells in estrogen-primed male rats. Acta Histochem 1993; 94:125-30. [PMID: 8351974 DOI: 10.1016/s0065-1281(11)80364-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
In order to evaluate the repercussions of estradiol treatment on the morphology and activity of FSH-producing cells, an immunocytochemical and morphometric study was carried out in male rats treated chronically with estradiol, relating those findings to serum FSH levels at the time of sacrifice. Chronic administration of estradiol led to a decrease (p < 0.01) in serum hormone levels that was accompanied by a marked decrease in cellular size (p < 0.01) due to a decrease in nuclear and cytoplasmic area. Our findings suggest for the adult male rat an inhibitory effect on the synthesis and release of FSH following testicular atrophy induced by treatment with estradiol.
Collapse
Affiliation(s)
- F Sánchez
- Department of Human Anatomy and Histology, University of Salamanca
| | | | | | | | | |
Collapse
|
23
|
Caruso A, Fortini A, Fulghesu AM, Pistilli E, Cucinelli F, Lanzone A, Mancuso S. Ovarian sensitivity to follicle-stimulating hormone during the follicular phase of the human menstrual cycle and in patients with polycystic ovarian syndrome. Fertil Steril 1993; 59:115-20. [PMID: 8419197 DOI: 10.1016/s0015-0282(16)55625-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
OBJECTIVE To investigate the existence of a different sensitivity of ovaries to follicle-stimulating hormone (FSH) during the follicular phase of the human menstrual cycle and in patients with polycystic ovarian syndrome (PCOS). DESIGN Thirty-four normal subjects and 13 patients with PCOS were treated intravenously by FSH (75 or 225 IU) or saline at different stages of follicular phase. MAIN OUTCOME MEASURES Plasma levels of luteinizing hormone (LH), FSH, estradiol (E2), and testosterone (T) in samples collected for a period of 26 hours after the injection. RESULTS In patients at the early stages of follicular phase (baseline E2 < 50 pg/mL), FSH increased in dose-dependent manner E2 and E2:T-stimulated area under curve (AUC) in respect to saline experiments. In PCOS subjects, saline E2, and E2:T-stimulated AUC were significantly lower than normal women. Follicle-stimulating hormone (75 IU) dramatically increased these values, and no difference was seen in respect to 75 and 225 IU FSH-treated controls. In patients with E2 baseline plasma levels > 50 pg/mL, FSH (75 or 225 IU) failed to increase both E2 and E2:T-stimulated AUC in comparison with saline studies. CONCLUSIONS Early stages of follicular phase in normal and polycystic ovaries are the most responsive to the elevation of circulating FSH levels, whereas the ovarian sensitivity spontaneously decreases as follicular maturation enhances.
Collapse
Affiliation(s)
- A Caruso
- Department of Obstetrics and Gynecology, Catholic University, Rome, Italy
| | | | | | | | | | | | | |
Collapse
|
24
|
Villars TA, Erskine MS, Lambert GM, Jacobson D, Weaver CE, Baum MJ. Endocrine correlates of mating-induced reductions in estrous behaviour in an induced ovulator, the ferret. Horm Behav 1990; 24:198-214. [PMID: 2365301 DOI: 10.1016/0018-506x(90)90005-i] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Experiments were conducted to assess the time course of behavioral and endocrine changes which occur in female ferrets as they switch from estrus to the pseudopregnant state. Significant reductions in females' acceptance of neck gripping by a stimulus male (receptivity) and in their latency to approach a stimulus male in an L-maze (proceptivity) were first observed 3 days after receipt of an intromission; no such changes occurred in other females which were only neck gripped by stimulus males during the initial test session. Corpora lutea were later found only in the ovaries of females which received intromissions, confirming that ovulation had occurred in these animals. Plasma concentrations of prostaglandin E1, prostaglandin F2 alpha, and the 13,14-dihydro 15-keto metabolite of prostaglandin F2 alpha (PGFM) were unchanged in female ferrets for 4-5 days after receipt of an intromission. By contrast, plasma concentrations of progesterone were significantly elevated beginning 5 days after, whereas plasma estradiol was significantly reduced beginning 4 days after receipt of an intromission. Daily sc administration of the progesterone receptor antagonist. RU 38486, significantly retarded the lengthening in females' approach latencies to a stimulus male, suggesting that postcoital elevations in circulating progesterone normally contribute to the expected decline in proceptive responsiveness. By contrast, postcoital reductions in acceptance quotients occurred at equivalent rates in females treated with RU 38486 versus vehicle, leading us to infer that postcoital reductions in estrogenic stimulation may cause this decline in ferrets' receptive responsiveness.
Collapse
Affiliation(s)
- T A Villars
- Department of Biology, Boston University, Massachusetts 02215
| | | | | | | | | | | |
Collapse
|
25
|
Ratka A, Simpkins JW. Dose-dependent effects of chronic treatment with estradiol or progesterone on LH secretion in ovariectomized rats. Endocr Res 1990; 16:165-84. [PMID: 2344834 DOI: 10.1080/07435809009032997] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Ovariectomized (OVX) Sprague-Dawley rats bearing atrial cannulae were implanted subcutaneously with fused pellets containing estradiol (E2) or progesterone (P4). Variable doses of E2 (0.1, 0.5, 1 and 5%) or P4 (10, 50, 75, 100%) were achieved by varying the ratio of the hormone to cholesterol (CHOL) in the pellet. Control groups were treated with CHOL containing pellets. Blood samples were collected in the morning and afternoon the day before and 1, 2, 5, 8, 11 and 14 days after pellet implantation. The concentrations of E2, P4 and LH were measured by RIA. Throughout the sampling period, plasma concentrations of both steroids were proportional to pellet composition. On days 1 and 2, high concentrations of E2 and P4 in plasma were obtained, but between days 5 and 14 stable levels at E2 and P4 were observed. The effectiveness of chronic replacement with E2 and P4 on the negative feedback on LH secretion was assessed from morning samples and positive feedback on LH from afternoon samples. E2 implants suppressed the morning LH levels in plasma in a time and dose-dependent manner. The afternoon concentrations of LH were significantly elevated on each sampling day, except for day 1. P4 pellets had no effect on morning-afternoon difference in LH level, but low doses suppressed LH shortly after the implantation and high doses suppressed LH level after the 8th day of implantation. These results indicate that fused pellets of E2 and P4 are effective in chronically maintaining plasma E2 and P4 at levels observed during various normal and pathological reproductive states. Further, these studies indicate that E2 can stimulate afternoon hypersecretion of LH for at least 14 days in ovariectomized rats.
Collapse
Affiliation(s)
- A Ratka
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville 32610
| | | |
Collapse
|
26
|
Devorshak-Harvey E, Bona-Gallo A, Gallo RV. Ovarian regulation of pulsatile luteinizing hormone secretion during late gestation in the rat*. J Neuroendocrinol 1989; 1:257-64. [PMID: 19210438 DOI: 10.1111/j.1365-2826.1989.tb00113.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Abstract The object of this study was to examine the influence of both estradiol (E(2)) and progesterone (P) alone or in combination on luteinizing hormone (LH) pulse amplitude and frequency during the interval between Days 21 and 22 of gestation. This was done by analyzing pulsatile LH release in rats bled on Days 21 and 22 of gestation, and in animals ovariectomized (OVX) on Day 21, implanted with silastic capsules producing plasma levels of E(2) and/or P characteristic of the Day 21 to 22 interval, and bled on Day 22 Pulsatile LH release increased between Days 21 and 22 due to an increase in pulse frequency and a small elevation in pulse amplitude. OVX produced no further increase in pulse frequency but markedly enhanced the small change in pulse amplitude. Preventing either the decline in plasma P that normally occurs between Days 21 and 22, or just the small additional decrease in plasma P levels produced by OVX, had no suppressive effect on pulse amplitude or frequency, although Day 22 levels of P alone augmented the normal increase in pulse frequency occurring between Days 21 and 22. Restoration of physiological plasma E(2) levels had no effect on the normal increase in pulse frequency, but partially attenuated the OVX-induced increase in pulse amplitude. Replacement of physiological Day 22 levels of both E(2) and P also decreased LH pulse amplitude, although amplitude was not significantly different from that seen following E(2) replacement alone, and was still greater than the normal Day 22 value. In contrast, restoration of physiological plasma levels of E(2)+ P caused a suppression of LH pulse frequency below that normally seen on Day 22. While E(2)+ P did not completely prevent the OVX-induced increase in pulse amplitude, administration of charcoal-extracted porcine follicular fluid to rats OVX on Day 21, and in which physiological plasma levels of E(2)+ P were restored, caused a further reduction in pulse amplitude. These data demonstrate that 1) marked increases in LH pulse amplitude are prevented from occurring between Days 21 and 22 of gestation by ovarian steroids, notably E(2), and that this suppression is enhanced by a non-steroidal factor present in porcine follicular fluid, 2) neither E(2) or P alone suppresses LH pulse frequency on Day 22 of gestation; LH pulse frequency increases on Day 22 because the plasma level of one of these steroids, P, markedly declines, and 3) restoration of physiological plasma levels of both steroids in the absence of the ovary produces an unphysiological suppression of pulse frequency, i.e. results in a lower pulse frequency than normally occurs in the presence of these same plasma steroid levels in animals with their ovaries intact. One hypothesis consistent with the latter observation is that at the end of gestation in the rat the ovary may produce a factor which 'protects' the frequency of the LH pulse generator from the negative feedback action of ovarian steroids. This allows an increase in LH pulse frequency and mean blood LH levels, and thereby facilitates ovarian follicular development and the normal progress of the first postpartum estrous cycle.
Collapse
Affiliation(s)
- E Devorshak-Harvey
- Department of Physiology and Neurobiology, The University of Connecticut, Storrs, Connecticut 06268, USA
| | | | | |
Collapse
|
27
|
Osborn RG, Biemer PP, Fuller GB, Hobson WC. Gonadotropin responsiveness to estrogens and low-level progesterone in the ovariectomized rhesus monkey. Reprod Toxicol 1989; 3:235-9. [PMID: 2535290 DOI: 10.1016/0890-6238(89)90017-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
When estrogen is administered to gonadectomized rhesus monkeys in sufficient quantity, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels are initially suppressed and gonadotropin secretion is subsequently augmented. This study was designed to examine the ability of various orally administered estrogens to elicit biphasic pituitary responses in adult castrate rhesus monkeys and to investigate the role of low-level progesterone in altering these responses. In an incomplete block design, 13 treatments were constructed: (E2): 0.5, 5.0, 50 micrograms/kg; (DES): 0.05, 0.5, 5.0 micrograms/kg; zearalenone (Z): 10, 100, 1000 micrograms/kg; or oil vehicle, each combined with progesterone. The remaining treatments (5.0, 0.5, and 100 micrograms/kg of E2, DES, and Z, respectively) did not include progesterone. During six intervals, E2, DES, or Z was administered orally on Days 1, 2, and 3 and blood was sampled on Days 0, 3, and 8 of each period. A main effect of estrogen treatment was observed for LH and FSH secretion on Day 3 but not Day 8. There was no main effect of progesterone alone on release of either LH or FSH on days 3 or 8, nor were significant carry-over effects of progesterone, E2, DES, or Z on LH or FSH concentration apparent by Day 8 of any treatment. However, progesterone synergized with E2 to suppress Day 3 LH levels. Conversely, DES and Z interacted with progesterone to facilitate LH secretion at this time.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- R G Osborn
- Division of Reproductive Biology, Primate Research Institute, Holloman AFB, NM 88330
| | | | | | | |
Collapse
|
28
|
Kesner JS, Wilson RC, Kaufman JM, Hotchkiss J, Chen Y, Yamamoto H, Pardo RR, Knobil E. Unexpected responses of the hypothalamic gonadotropin-releasing hormone "pulse generator" to physiological estradiol inputs in the absence of the ovary. Proc Natl Acad Sci U S A 1987; 84:8745-9. [PMID: 3317420 PMCID: PMC299623 DOI: 10.1073/pnas.84.23.8745] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
In the rhesus monkey (Macaca mulatta), the frequency of pulsatile gonadotropic hormone release is relatively constant in the face of widely varying levels of estradiol (E2) in the peripheral circulation--e.g., in the course of the follicular phase of the menstrual cycle and after ovariectomy. This suggests that modulation of the hypothalamic gonadotropin-releasing hormone (GnRH) "pulse generator" by this steroid is not of major physiological importance. Herein is described the unexpected inhibition or total blockade of the electrical activity of this pulse generator in ovariectomized monkeys by physiological levels of exogenous E2. This inhibition began 2-4.5 hr after the initiation of E2 infusion and was noted 1 to 3 weeks after subcutaneous implantation of E2-containing capsules. Pulse generator activity was also arrested during the initiation and subsequent development of estrogen-induced surges of luteinizing hormone. We propose that this inhibition of hypothalamic GnRH pulse generator activity by E2 in ovariectomized monkeys reflects the absence of an ovarian factor that normally protects this neuronal system from the inhibitory action of estrogen during the menstrual cycle.
Collapse
Affiliation(s)
- J S Kesner
- Laboratory for Neuroendocrinology, University of Texas Health Science Center Medical School, Houston 77225
| | | | | | | | | | | | | | | |
Collapse
|
29
|
Veldhuis JD, Evans WS, Rogol AD, Thorner MO, Stumpf P. Actions of estradiol on discrete attributes of the luteinizing hormone pulse signal in man. Studies in postmenopausal women treated with pure estradiol. J Clin Invest 1987; 79:769-76. [PMID: 3818948 PMCID: PMC424195 DOI: 10.1172/jci112883] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
We assessed the time-dependent impact of estradiol on properties of the luteinizing hormone (LH) pulse signal in 12 hypoestrogenemic postmenopausal volunteers studied basally and after 1, 5, 10, and 30 d of estradiol delivery via an intravaginal Silastic ring. Computerized analysis of the plasma LH time series revealed a significant decrease in LH pulse frequency within 24 h of estrogen treatment, followed by a secondary increase (days 5 and 10), and then a sustained decline (day 30) in LH pulsatility. Estradiol also significantly suppressed incremental and maximal (but not fractional) LH pulse amplitudes in a biphasic manner. In contrast, LH peak duration was invariant until day 30 of estradiol replacement. These observations indicate that the well recognized biphasic actions of estradiol on mean serum LH concentrations can be modeled in relation to specific and time-dependent alterations in LH pulse frequency and amplitude.
Collapse
|
30
|
Abstract
The present study evaluated the facilitative actions of progesterone and the synthetic progestin R 5020 on estrous responsiveness in ovariectomized, estrogen-primed female rats. The dose-response and time-response characteristics of the behavior facilitating actions of both progesterone and R 5020 were measured. The threshold doses for the facilitation of estrous behavior in estrogen-primed female rats were 1 microgram of R 5020 and 100 micrograms of progesterone. These doses of progestins facilitated estrous responsiveness with a similar time course that approached maximum at one hour. To examine the possible mechanism(s) of action of each progestin the synthetic progestin antagonist RU 38486 was used. The inhibitory effects of RU 38486 on estrous behavior facilitated by a threshold dose of progesterone or R 5020 were found to be almost identical. RU 38486 (5 mg) administered 1 hr prior to progesterone or R 5020 suppressed lordosis behavior by 44% and 47% respectively. These results suggest that progesterone and R 5020 facilitate estrous responsiveness through the same mechanism.
Collapse
Affiliation(s)
- I U Vathy
- Department of Psychology, Rutgers University, New Brunswick, NJ 08903
| | | | | |
Collapse
|
31
|
Baum MJ, Gerlach JL, Krey LC, McEwen BS. Biochemical and radioautographic analysis of estrogen-inducible progestin receptors in female ferret brain and pituitary: correlations with effects of progesterone on sexual behavior and gonadotropin-releasing hormone-stimulated secretion of luteinizing hormone. Brain Res 1986; 368:296-309. [PMID: 3516305 DOI: 10.1016/0006-8993(86)90574-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Cytosolic binding molecules for the synthetic progestin [3H]R5020, were isolated in vitro from several brain regions including preoptic area/anterior hypothalamus, mediobasal hypothalamus, medial amygdala and parietal cortex as well as the pituitary gland of ovohysterectomized female ferrets. Binding of [3H]R5020 to cortical cytosols was saturable, of high affinity (apparent dissociation constant of 2.0 nM), and was steroid specific. Pretreatment of ferrets with a Silastic capsule containing estradiol caused significant increments in the concentration of cytosolic R5020 binding sites in hypothalamus and pituitary gland, but not in the other brain regions studied. Brains of additional ovohysterectomized ferrets, which had been primed with estradiol prior to receiving an i.v. injection of [3H]R5020, were processed radioautographically. Intense labeling of cells was seen in the medial and lateral preoptic area, in the lateral hypothalamus, and in the ventromedial and arcuate nuclei of the hypothalamus. Radioautograms from the brains of additional ovohysterectomized ferrets given an i.v. injection of [3H]estradiol revealed labeled cells in all of the above regions, in addition to the basolateral portion of the septum, the bed nucleus of the stria terminalis, and in the anterior amygdaloid area as well as the medial and cortical nuclei of the amygdala. This distribution of neural progestin and estrogen binding sites resembles those previously reported for these steroids in the rat, guinea pig, hamster and macaque. Functional studies showed that acute s.c. implantation of a Silastic capsule containing progesterone to ovohysterectomized ferrets, which had been primed with a low dosage of estradiol, failed to augment their sexual receptivity in limited tests with stimulus males given 4 and 8 h after progesterone treatment. This result contrasts with the well-established facilitatory effect of progesterone on sexual receptivity in rat and guinea pig. Chronic exposure to a progesterone capsule caused significant reductions in sexual receptivity in ovohysterectomized ferrets which were implanted concurrently with a second Silastic capsule containing a high dosage of estradiol. Similar effects of progesterone have been reported in rat and guinea pig, but not in the rhesus monkey. Thus species differences in the ability of progesterone to facilitate or inhibit sexual receptivity are not readily explained by species differences in the neural distribution of estrogen-induced progestin receptors.(ABSTRACT TRUNCATED AT 400 WORDS)
Collapse
|
32
|
Chrousos GP, MacLusky NJ, Brandon DD, Tomita M, Renquist DM, Loriaux DL, Lipsett MB. Progesterone resistance. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1986; 196:317-28. [PMID: 3087144 DOI: 10.1007/978-1-4684-5101-6_21] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
|
33
|
Rees HD, Bonsall RW, Michael RP. Localization of the synthetic progestin 3H-ORG 2058 in neurons of the primate brain: evidence for the site of action of progestins on behavior. J Comp Neurol 1985; 235:336-42. [PMID: 3998214 DOI: 10.1002/cne.902350305] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The location of neurons that concentrate progestin in the brains of female cynomolgus monkeys was mapped by autoradiography using the specific synthetic progestin receptor ligand 3H-ORG 2058. Three females were ovariectomized and treated with estrogen (20 micrograms estradiol benzoate daily for 7 days), and one of them was also pretreated with progesterone. Each received an i.v. injection of 1 mCi 3H-ORG 2058 and was killed 1 hour later. Thaw-mount autoradiograms revealed intense accumulation of radioactivity in the nuclei of many neurons in the mediobasal hypothalamus, particularly in the ventromedial nucleus (n.), arcuate n., and premammillary n. Neuronal labeling was also observed frequently in the medial preoptic n., and occasionally in the anterior hypothalamic area, paraventricular n., and organum vasculosum of the lamina terminalis. In the pituitary gland, about 5% of cells in the pars distalis were intensely labeled. In the female pretreated with progesterone, however, labeling was almost completely blocked. Analysis of samples by high-performance liquid chromatography demonstrated that the radioactivity extracted from brain and pituitary gland cell nuclei was almost entirely unmetabolized 3H-ORG 2058. The nuclear concentration of progestin was much greater in the pituitary gland than in the brain, and was greater in the hypothalamus than in any other brain area. These results revealed well-localized groups of progestin-concentrating neurons in the primate brain which presumably mediate the effects of progesterone on both gonadotropin secretion and female sexual behavior.
Collapse
|
34
|
|
35
|
|
36
|
Kemeter P, Bernaschek G, Altmann G, Feichtinger W. The effect of 2 mg estradiol-17 beta plus 1 mg estriol, sequentially combined with 1 mg norethisteroneacetate, on LH, FSH, estradiol-17 beta, progesterone, testosterone and prolactin after ovariectomy. ARCHIVES OF GYNECOLOGY 1984; 234:219-29. [PMID: 6428330 DOI: 10.1007/bf00570759] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The object of the study was to see whether maintenance of serum estradiol levels corresponding to the early and mid-follicular phase can prevent the gonadotrophin increase following ovariectomy. We also wanted to study the effect on LH and FSH of an additional dose of 1 mg dose of 1 mg norethisterone acetate administered for 10 days during each month. In 22 women with normal cycles 1 mg of estradiol benzoate was injected i.m. at the time of ovariectomy. From the first post-operative day onwards they received daily doses of 2 mg estradiol and 1 mg estriol in the form of micronized tablets. From the 41st to the 50th day and again from the 69th to the 78th day the patients received additional daily doses of 1 mg norethisterone acetate. LH, FSH, estradiol-17 beta, (E2) progesterone (P), testosterone (T), and prolactin (PRL) were measured in intervals of 2-17 days. Even though the estradiol mean values remained constant in the range of 65-115 pg throughout the period under observation, the LH mean levels increased continuously from 8 to a maximum of 23.9 mU/ml, and the FSH mean level from a pre-operative value of 6-48.0 mU/ml on the 85th day. On the 7th day after the last administration of norethisterone acetate LH was slightly depressed while FSH continued to rise slightly. Both FSH and LH are negatively correlated with E2 and this inverse correlation becomes even more pronounced the more time has elapsed after surgery. These findings suggest that not only the estrogens inhibit FSH and LH but also other steroids and/or nonsteroidal ovarian inhibiting factors.
Collapse
|
37
|
Attardi B. Multiple forms of nuclear estrogen receptor in the hypothalamus and pituitary after in vitro exchange with [3H]estradiol or [3H]hydroxytamoxifen. Mol Cell Endocrinol 1983; 29:147-57. [PMID: 6832468 DOI: 10.1016/0303-7207(83)90209-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
|
38
|
Channing CP, Anderson LD, Hoover DJ, Kolena J, Osteen KG, Pomerantz SH, Tanabe K. The role of nonsteroidal regulators in control of oocyte and follicular maturation. RECENT PROGRESS IN HORMONE RESEARCH 1982; 38:331-408. [PMID: 6289394 DOI: 10.1016/b978-0-12-571138-8.50014-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
|
39
|
Lacker HM. Regulation of ovulation number in mammals. A follicle interaction law that controls maturation. Biophys J 1981; 35:433-54. [PMID: 6791721 PMCID: PMC1327533 DOI: 10.1016/s0006-3495(81)84800-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The assumption that developing follicles communicate through circulating hormones has been used to obtain a class of interaction laws that describe follicle growth. A specific member of this class has been shown to control ovulation number. Although all interacting follicles obey the same growth law and are given initial maturities that are chosen at random from a uniform distribution, ovulatory and atretic follicles emerge. Changing the parameters in the growth law can alter the most probable ovulation number values, anovulatory states are also admitted as possible solutions of the growth law. The behavior of the model is examined for interacting follicle populations of different size. Methods are suggested for identifying growth laws in particular mammals. These can be used to test the model from experimental data.
Collapse
|
40
|
Resko JA, Ellinwood WE, Knobil E. Differential effects of progesterone on secretion of gonadotropic hormones in the rhesus monkey. THE AMERICAN JOURNAL OF PHYSIOLOGY 1981; 240:E489-92. [PMID: 6786104 DOI: 10.1152/ajpendo.1981.240.5.e489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
To obtain new information on the site of the inhibiting actions of progesterone (P) during the follicular phase of the cycle, we administered P continuously to 13 rhesus macaques (Macaca mulatta) from days 5 through 12 of the menstrual cycle. This treatment produced luteal-phase levels (approximately 6 ng/ml of serum) within 4 h. (FSH) concentrations dropped significantly from pretreatment amounts (P less than 0.01). During this time, both immunoreactive luteinizing hormone (LH) (n = 8 animals) and bioactive LH (n = 5) remained stable. The 17 beta-estradiol (E2) concentrations dropped significantly below base line 24 h after treatment (P less than 0.05). The decline in E2 occurred after the decline in FSH. Inhibition of FSH continued for 40 h, after which both FSH and LH rose steadily in a way that resembled a preovulatory surge on days 8 or 9 of the menstrual cycle, and then returned to base line by day 10. When gonadotropins were at their zenith, the ovary did not respond by secreting E2. None of the effects mentioned above were found in control animals treated with blank implants. These data demonstrate that P administered during the follicular phase inhibits FSH but not LH secretion. This initial inhibition probably occurs at a hypothalamic-pituitary site, but after 40 h direct inhibitory effects on the ovary cannot be ruled out. P stimulates the release of gonadotropin in female monkeys despite reduced production of E2 by the ovary.
Collapse
|
41
|
Nozu K, Dufau M, Catt K. Estradiol receptor-mediated regulation of steroidogenesis in gonadotropin-desensitized Leydig cells. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)69894-7] [Citation(s) in RCA: 85] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
|
42
|
Umberkoman-Wiita B, Kumar TC. Association of tritiated ovarian steroids with the rhesus monkey brain. JOURNAL OF STEROID BIOCHEMISTRY 1979; 11:809-18. [PMID: 114717 DOI: 10.1016/0022-4731(79)90016-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
43
|
Wiele RL, Antunes JL, Ferin M. Neural control of gonadotropin secretion in primates. Am J Obstet Gynecol 1978; 132:752-7. [PMID: 102199 DOI: 10.1016/s0002-9378(78)80009-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In the rhesus monkey, there is abundant evidence to indicate that ovarian secretions, mainly estradiol-17beta, control "tonic" as well as "cyclic" secretion of gonadotropins during the menstrual cycle. This mechanism of control ensures coordination of ovarian morphology and anterior pituitary secretory patterns. The primary site of action of estradiol in controlling both "tonic" and "cyclic" secretion of gonadotropins has been circumscribed to the medial basal hypothalamic-pituitary unit. A modulatory role in "cyclic" secretion by neural structures situated within the anterior hypothalamic-preoptic area or by efferent fibers in passage through this region also has been postulated. However, the accrued evidence indicates that in the primate, contrary to the rodent, the role of these rostral neural structures is not essential for menstrual cyclicity. Strong evidence also indicates that the isolated pituitary gland can respond to estrogen signals as well. Secretion of gonadotropin-releasing hormone, the hypothalamic decapeptide, into the long portal vessels is, however, essential to maintain function of the gonadotroph. Further, pulsatile release of luteinizing hormone is distinctly under the control of a similarly paced hypothalamic clock.
Collapse
|
44
|
Hobson W, Bailey J, Fuller GB. Hormone effects of zearalenone in nonhuman primates. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH 1977; 3:43-57. [PMID: 411943 DOI: 10.1080/15287397709529548] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
45
|
Kragt CL, Gala RR. Luteinizing hormone-releasing hormone, ovariectomy, and silastic vaginal rings in the Rhesus monkey. Fertil Steril 1977; 28:856-62. [PMID: 407108 DOI: 10.1016/s0015-0282(16)42741-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The interaction of estradiol and luteinizing hormone-releasing hormone (LRH) may be a critical physiologic mechanism regulating the occurrence of ovulation in many species. These studies were conducted to assess (1) the effects of intramuscular injections of LRH in the intact female rhesus monkey and (2) the effects of estradiol in a Silastic delivery system in ovariectomized female rhesus monkeys. No changes in blood levels of luteinizing hormone (LH) were detected in response to 200 micrograms of LRH. Ovulation did not occur 48 hours after treatment. Ovariectomy decreased estradiol, increased LH, and had no effect on prolactin concentrations in sera. Insertion of a vaginal ring containing 10% estradiol increased blood estradiol levels 100-fold. Serum prolactin levels were unaffected; however, LH concentrations were altered in a multiphasic fashion. After the ring had been in place for 15 days, vaginal blood similar to menstrual flow was observed following removal.
Collapse
|
46
|
Gerlach JL, McEwen BS, Pfaff DW, Moskovitz S, Ferin M, Carmel PW, Zimmerman EA. Cells in regions of rhesus monkey brain and pituitary retain radioactive estradiol, corticosterone and cortisol differentially. Brain Res 1976; 103:603-12. [PMID: 175885 DOI: 10.1016/0006-8993(76)90463-7] [Citation(s) in RCA: 66] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
47
|
Knobil E. On the control of gonadotropin secretion in the rhesus monkey. RECENT PROGRESS IN HORMONE RESEARCH 1974; 30:1-46. [PMID: 4210416 DOI: 10.1016/b978-0-12-571130-2.50005-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|