Abstract:
:We have previously reported that luteinizing hormone releasing hormone (LH-RH) levels in the medial basal hypothalamus (MBH) of adult male rats castrated for 2 weeks can be raised by testosterone (T) or estradiol (E2) treatment for 3-4 days. The present study was undertaken to determine the time after castration when the hypothalamus becomes refractory to this feedback action and whether prolongation of exposure to steroids would reinstate the hypothalamic LH-RH response. Treatment with T (Silastic capsules, s.c.) for 4 days, when commenced either immediately or 14 days after castration, significantly raised the MBH LH-RH levels. A 4-day regimen of E2 or dihydrotestosterone, on the other hand, evoked similar increase when commenced up to 21-28 days after castration. Further delay in institution of the 4-day treatment rendered the three steroids completely ineffective. When the effects of prolongation of treatment were tested in long-term castrated rats (56 days), it was found that T required 14 days as compared to 7 days of exposure with E2 or dihydrotestosterone to produce an equivalent MBH LH-RH response. Furthermore, the MBH LH-RH and serum LH responses were not always correlated, since increments in the MBH LH-RH were observed when serum LH levels were suppressed by physiological levels of T or dihydrotestosterone and also when they were unchanged with low levels of T or E2. These studies show that long-term castration causes a dichotomy in responsiveness of the hypothalamo-pituitary axis to steroids.(ABSTRACT TRUNCATED AT 250 WORDS)
journal_name
Neuroendocrinologyjournal_title
Neuroendocrinologyauthors
Kalra PSdoi
10.1159/000124188subject
Has Abstractpub_date
1985-09-01 00:00:00pages
219-23issue
3eissn
0028-3835issn
1423-0194journal_volume
41pub_type
杂志文章abstract:AIM:To extensively explore microRNA expression profiles in lung carcinoids in correlation with clinical and pathological features. METHODS:A PCR-based array was employed in the screening phase to analyze 752 microRNAs in a discovery set of 12 lung carcinoids, including 6 typical (3 with lymph node metastasis) and 6 at...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000381454
更新日期:2015-01-01 00:00:00
abstract::Hypothalamic norepinephrine (NE) and dopamine content was studied in dogs with spontaneous and iatrogenic hypercortisolism and in untreated normal dogs. The concentration of NE in the hypothalamus was subnormal in 4 of 8 dogs with pituitary-dependent hyperadrenocorticism (PDH), whereas long-term administration of cort...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000123158
更新日期:1981-04-01 00:00:00
abstract::Previous studies have shown that prepubertal olfactory bulbectomy will prevent the testicular regression associated with short photoperiod in golden hamsters. The gonadal regression which normally occurs in hamsters on short photoperiod is known to be due in part to an increased responsiveness of the reproductive neur...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124839
更新日期:1987-10-01 00:00:00
abstract::It is now well documented that various polyclonal antisera to the human growth hormone-releasing factor (hGHRF, somatocrinin) visualize in the brain by immunohistochemistry the classical hypothalamic hypophysiotropic neurons and also antigens present in otherwise characterized peptidergic neuronal systems. The nature ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000125370
更新日期:1990-04-01 00:00:00
abstract:BACKGROUND:Neuroendocrine tumors (NETs) are rare and characterized by a heterogeneous clinical course and an unmet need for better prognostic markers. Plasma cell-free DNA (cfDNA) has prognostic value in other malignancies but is not previously investigated in NETs. We studied cfDNA levels in patients with mainly low g...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000514457
更新日期:2021-01-18 00:00:00
abstract::The differential role of porcine follicular fluid (pFF) in regulating follicle-stimulating hormone (FSH) and luteinizing hormone (LH) release in vivo in situations of different gonadotropin releasing hormone (GnRH) backgrounds was studied. In experiment 1, 2-week ovariectomized rats injected intravenously with 4, 16 o...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000123891
更新日期:1984-03-01 00:00:00
abstract::Follicle-stimulating hormone (FSH) is involved in the regulation and maintenance of gametogenesis. It exists in multiple molecular forms with different oligosaccharide structures which in turn are influenced by the hormonal milieu. Previous studies from our laboratory demonstrated that antiandrogen administration to i...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000054484
更新日期:1999-10-01 00:00:00
abstract::Progesterone is readily reduced in humans to its A-ring metabolites, allopregnanolone (3 alpha-hydroxy-5 alpha-pregnan-20-one) and pregnanolone (3 alpha-hydroxy-5 beta-pregnan-20-one). The latter have been reported to have anxiolytic, hypnotic and anesthetic actions when administered to laboratory animals and (or) hum...
journal_title:Neuroendocrinology
pub_type: 临床试验,杂志文章,随机对照试验
doi:10.1159/000126579
更新日期:1993-10-01 00:00:00
abstract::To determine whether the inhibitory effect of clonidine (CLON) on renin secretion is due in part to a direct action on the kidneys or due entirely to an action on the brain, the drug was administered intravenously in a dose of 30 microgram/kg to dogs in which the spinal cord had been transected in the cervical region....
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000122733
更新日期:1978-01-01 00:00:00
abstract::Dehydration is a classic homeostatic stressor in rats that leads to a series of endocrine responses including stimulation of the hypothalamo-pituitary-adrenal (HPA) axis. During the last decade, it has been well established that perinatal food restriction is associated with the onset of diseases in adults. Our previou...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000078098
更新日期:2004-01-01 00:00:00
abstract::An experiment was performed on 21-day-old male rats to determine the combined effects of pinealectomy, constant light and darkness, and intraperitoneal (i.p.) thyrotropin-releasing hormone (TRH) on pituitary and plasma radioimmunoassayable thyrotropin (TSH), serum thyroxine (T4), and pituitary, thyroid and body weight...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000122751
更新日期:1978-01-01 00:00:00
abstract::Pit-1 expression has been reported to be cell-type-specific in the adult human pituitary and in human pituitary adenomas. In contrast, studies of rodent fetal adenohypophysial development as well as mature rodent glands have indicated that the pit-1 mRNA is ubiquitously expressed and the protein is under translational...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126975
更新日期:1996-04-01 00:00:00
abstract::The effect of pinealectomy or immunization against melatonin (Mel) and N-acetylserotonin (NAS) on plasma prolactin (Prl) levels was studied in rats following pineal stimulation induced by blinding or exposure to short photoperiods (1 h light and 23 h darkness daily). Blinding alone or together with pinealectomy or imm...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000122650
更新日期:1977-01-01 00:00:00
abstract::The purpose of these studies was to determine the temporal requirements and time of day required for progesterone (P4) to amplify versus extinguish LH surges. The experimental animal model used in these studies was the 7-day ovariectomized rat (day 0) treated continuously with estradiol (E2) for 2-4 days (days 2, 3 or...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124241
更新日期:1986-01-01 00:00:00
abstract::The present study provides evidence of a novel neuronal pathway for the control of GnRH secretion involving bradykinin neurons. Bradykinin neurons were shown by immunohistochemistry to be densely localized in several regions of the brain including the cortex, hippocampus and supraoptic nucleus, as well as two regions ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000054316
更新日期:1998-04-01 00:00:00
abstract::The mechanisms by which leptin influences energy homeostasis are not entirely understood. Several observations indicate that proopiomelanocortin (POMC) is involved in the regulation of food intake and may be a mediator of leptin action. To further study this interaction, a sensitive solution hybridization assay was us...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000054499
更新日期:1999-12-01 00:00:00
abstract::The site of inhibitory action of glucocorticoids on the hypothalamic corticotropin-releasing factor (CRF) and arginine vasopressin (AVP) was studied using a combination of glucocorticoid implantation and immunohistochemistry. Adrenalectomy increased the number and the staining intensity of the neurons containing CRF-l...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124650
更新日期:1986-01-01 00:00:00
abstract::Observations of long standing have suggested that the 'stress' of chair restraint inhibits the GnRH pulse generator in normal female monkeys while this phenomenon is rarely observed in ovariectomized animals. The role of the ovary in the response of the GnRH pulse generator to the stress of insulin hypoglycemia was in...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126291
更新日期:1992-11-01 00:00:00
abstract::We have investigated the effects of hyperprolactinemia, produced by pituitary isografts under the kidney capsule (16-20 days), on the LH releasing action and priming effect of LH-releasing hormone (LHRH) in normal and hypogonadal (hpg) female mice. The pituitary grafts increased the plasma prolactin concentrations abo...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124585
更新日期:1986-01-01 00:00:00
abstract::The purpose of the present study was to examine whether repetitive intravenous injections of L-glutamic acid (Glu), like those of N-methyl-D,L-aspartic acid (NMA), are able to elicit a sustained train of gonadotropin releasing hormone (GnRH) discharges from the hypothalamus of the prepubertal male monkey. In order to ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126186
更新日期:1992-06-01 00:00:00
abstract::Dexras1, a newly identified member of the Ras superfamily of proteins, was discovered in AtT-20 corticotrope cells because its expression was induced in response to glucocorticoids (dexamethasone; Dex). As yet, the function of Dexras1 is unknown, but its rapid induction in response to glucocorticoids suggests the poss...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000054691
更新日期:2001-10-01 00:00:00
abstract::Brain sexual differentiation is mediated through testosterone, which acts during the perinatal period in the form of both 5alpha-dihydrotestosterone and estradiol. In order to gain insight into the molecular mechanisms involved, we studied induction of c-fos, an index of functional neuronal activation, in the 2-day-ol...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000054657
更新日期:2001-06-01 00:00:00
abstract::Amygdalotomized, sham-operated and intact wild-derived house mice of both sexes were group-caged (8-10) or singly caged for 3 weeks. The weights of ovaries (p is less than 0.05) and uteri (p is less than 0.01) were less in intact and sham-operated grouped females compared to singly caged intact and amygdalotomized fem...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000122731
更新日期:1978-01-01 00:00:00
abstract::The effects of intracerebroventricularly (i.c.v.) injected interleukin-1 beta (IL-1 beta: 1, 2.5, 10, and 25 ng) were studied on plasma growth hormone (GH) and prolactin (PRL) concentrations in freely moving rats chronically implanted with i.c.v. cannulas and intracardial catheters. Significant changes in PRL secretio...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126217
更新日期:1992-07-01 00:00:00
abstract:INTRODUCTION:Several studies have suggested that diet, especially one enriched in microbiota-fermented fibers or fat, regulates behavior. The underlying mechanisms are currently unknown. We previously reported that certain macronutrients (fermentable fiber and protein) regulate energy homeostasis via the activation of ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000514289
更新日期:2021-01-11 00:00:00
abstract::Normal and castrated male rats implanted with permanent right atrial cannulae were used, and sequential blood samples were taken every 2 min through the cannula. When the rats, both normal and castrated, were exposed to ether for 2 min, the prolactin (Prl) concentration in plasma was immediately and dramatically eleva...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000122826
更新日期:1978-01-01 00:00:00
abstract::The role of endogenous corticoids in fever responses caused by recombinant murine interleukin (IL)-1 beta and IL-6 was studied in adult male Wistar rats. Adrenalectomy diminished the development of fever after intracerebroventricular (icv) injection of these ILs and lowered body temperature. Intraperitoneal administra...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126682
更新日期:1994-04-01 00:00:00
abstract::Neonatal rats exhibit a period of diminished pituitary and adrenocortical responses to stress during the first 2 weeks of life. Since thyroid hormones are known to affect brain development, modulation of these responses to stress by alterations in thyroid hormone status have been investigated in hypothyroid (Hypo) and...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000125232
更新日期:1989-09-01 00:00:00
abstract::We have used excitatory amino acids as tools to elucidate changes in hypothalamic function associated with lactation, focusing on the regulation of luteinizing hormone (LH) and prolactin secretion. In these studies, we have compared the responsiveness to NMA (N-methyl-D,L-aspartate), an agonist for the N-methyl-D-aspa...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126576
更新日期:1993-10-01 00:00:00
abstract::Chronic exposure to Delta(9)-tetrahydrocannabinol (Delta(9)-THC) increases corticotropin-releasing hormone (CRH) and proopiomelanocortin (POMC) gene expression in the rat hypothalamus. The levels of circulating gonadal steroids concurrently modulate both neuropeptides in male and female rats. However, it remains unkno...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000054685
更新日期:2001-09-01 00:00:00