SERUM LEVELS OF GONADOTROPHINS IN HAMSTERS EXPOSED TO SHORT PHOTOPERIODS: EFFECTS OF ADRENALECTOMY AND OVARIECTOMY

1979 ◽  
Vol 83 (1) ◽  
pp. 113-118 ◽  
Author(s):  
E. L. BITTMAN ◽  
B. D. GOLDMAN
Keyword(s):  
Adrenal Glands ◽  
Serum Levels ◽  
Adrenal Steroids ◽  
Gonadotrophin Secretion ◽  
Neuroendocrine Axis ◽  
The Brain ◽  
Short Days

SUMMARY Female hamsters rendered acyclic by exposure to short photoperiods (10 h light: 14 h darkness) showed diurnal surges of both LH and FSH which persisted after removal of the ovaries and adrenal glands. The reduced increase in gonadotrophin secretion after ovariectomy, typical of hamsters exposed to short days, was also not contingent upon the presence of the adrenal glands. The results demonstrate that 'supersensitivity' of the neuroendocrine axis to feedback of ovarian or adrenal steroids cannot fully account for either the daily surges of gonadotrophins or the diminished response of LH and FSH to ovariectomy in hamsters maintained on short days. It is suggested that these changes result instead from other pineal-mediated actions of short photoperiods upon the brain.

ADRENERGIC INPUTS TO THE AMYGDALA AND THE CONTROL OF GONADOTROPHIN RELEASE

1979 ◽  
Vol 90 (3) ◽  
pp. 385-393 ◽  
Author(s):  
José Borrell ◽  
Flavio Piva ◽  
Luciano Martini
Keyword(s):  
Brain Stem ◽  
Dopamine Receptor ◽  
Serum Levels ◽  
Female Rats ◽  
Receptor Blocker ◽  
Dopaminergic Drug ◽  
Gonadotrophin Secretion ◽  
Biphasic Effect ◽  
Adrenergic Blocker ◽  
The Brain

ABSTRACT Drugs able to mimic or to antagonize the action of catecholamines have been implanted bilaterally into the basomedial region of the amygdala of adult castrated female rats. The animals were killed at different intervals after the implantation of the different drugs, and serum levels of LH and FSH were measured by radioimmunoassay. The results have shown that the intra-amygdalar implantation of the alpha-adrenergic blocker phenoxybenzamine induces a significant increase of the release both of LH and FSH. The implantation of the beta-adrenergic blocker propranolol brings about a rise of LH only. The dopamine receptor blocker pimozide stimulates the release of LH and exerts a biphasic effect (stimulation followed by inhibition) of FSH secretion. The alpha-receptor stimulant clonidine and the dopaminergic drug 2-Br-alpha-ergocryptine were without significant effects. From these observations it is suggested that the adrenergic signals reaching the basomedial area of the amygdala (possibly from the brain stem) may be involved in the modulation of gonadotrophin secretion.

scholarly journals Thyroid hormones and seasonal reproductive neuroendocrine interactions

Reproduction ◽  
2008 ◽  
Vol 136 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Nobuhiro Nakao ◽  
Hiroko Ono ◽  
Takashi Yoshimura
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Biological Process ◽  
Critical Role ◽  
Day Length ◽  
Seasonal Reproduction ◽  
Seasonal Breeding ◽  
Length Changes ◽  
Neuroendocrine Axis ◽  
The Brain

Many animals that breed seasonally measure the day length (photoperiod) and use these measurements as predictive information to prepare themselves for annual breeding. For several decades, thyroid hormones have been known to be involved in this biological process; however, their precise roles remain unknown. Recent molecular analyses have revealed that local thyroid hormone activation in the hypothalamus plays a critical role in the regulation of the neuroendocrine axis involved in seasonal reproduction in both birds and mammals. Furthermore, functional genomics analyses have revealed a novel function of the hormone thyrotropin. This hormone plays a key role in signaling day-length changes to the brain and thus triggers seasonal breeding. This review aims to summarize the currently available knowledge on the interactions between elements of the thyroid hormone axis and the neuroendocrine system involved in seasonal reproduction.

Meetings of medical societies. Society of Physicians at Kazan University

1927 ◽  
Vol 23 (4) ◽  
pp. 475-479
Keyword(s):  
Clinical Significance ◽  
Microscopic Examination ◽  
Adrenal Glands ◽  
Practical Importance ◽  
Artificial Damage ◽  
Medical Societies ◽  
Brain Substance ◽  
The Brain

Meeting of February 24Prof. M. N. Cheboksarov: Adrenal lipase, its relation to poisons and clinical significance. The report was printed in issue 3 of "K.M. Journal". In the debate Prof. P.P. Vasiliev pointed out that microscopic examination of the adrenal glands of dead B., mentioned by the reporter, revealed the existence of changes both in the cortical and in the brain substance of them. Proff. С. С. Zimnitskii and P. N. Nikolaev, noting the practical importance and interest of the reporter's work, pointed out that it would be especially interesting to trace the content of adrenal lipase in such diseases as typhoid and typhoid, as well as in animals with artificial damage to their adrenal glands.

scholarly journals Clozapine Use Presenting with Pseudopheochromocytoma in a Schizophrenic Patient: A Case Report

2013 ◽  
Vol 2013 ◽  
pp. 1-3 ◽  
Author(s):  
Jaskanwal Sara ◽  
Matt Jenkins ◽  
Tanveer Chohan ◽  
Karan Jolly ◽  
Lisa Shepherd ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Adrenal Glands ◽  
Serum Cortisol ◽  
Serum Levels ◽  
Urinary Free Cortisol ◽  
Free Cortisol ◽  
History Of ◽  
Caucasian Female ◽  
Abnormal Uptake ◽  
Noradrenaline Levels

Introduction. There have been six previous cases that reported pseudopheochromocytoma in patients taking clozapine. Our case showed the direct link of clozapine to serum levels of certain markers.Case. This is a case of a 49-year-old obese Caucasian female who was referred to endocrinology for investigation of Cushing’s syndrome, based on raised blood pressure and Cushingoid facies. The patient had underlying schizophrenia and was stable on clozapine. Her blood pressure was 150/99 mmHg on bendroflumethiazide and candesartan. We measured her 24-hour urinary-free cortisol, which was normal but 24-hour urinary-free noradrenaline was elevated at 835 nmol (76–561) with normal adrenaline 36 nmol (7–82) and dopamine 2679 nmol (366–2879), as the patient had history of palpitations and sweating. Two sets of 24-hour urinary-free cortisol measurements were normal and serum cortisol suppressed to <50 nmol/l after a 1 mg overnight dexamethasone. Two further 24-hour urinary-free catecholamines showed a raised level of noradrenaline. MRI demonstrated normal adrenals and MIBG scan did not show any abnormal uptake at adrenal glands.Conclusion. Pseudopheochromocytoma has been reported in patients taking clozapine. A number of different mechanisms for raised plasma noradrenaline levels with clozapine have been postulated. The above case highlights an unusual but known side effect of clozapine.

scholarly journals Effect of different types of stress on adrenal gland parameters and adrenal hormones in the blood serum of male Wistar rats

2009 ◽  
Vol 61 (2) ◽  
pp. 187-194 ◽  
Author(s):  
M. Adzic ◽  
Ana Djordjevic ◽  
Jelena Djordjevic ◽  
Ana Niciforovic ◽  
Marija Radojcic
Keyword(s):  
Blood Serum ◽  
Wistar Rats ◽  
Adrenal Glands ◽  
Acute Stress ◽  
Serum Levels ◽  
Combined Stress ◽  
Adrenal Hormones ◽  
General Adaptation ◽  
Different Types ◽  
Male Wistar Rats

In the present study, we examined gross changes in the mass of whole adrenal glands and that of the adrenal cortex and medulla in mature male Wistar rats subjected to three different stress types: acute, chronic, and combined, i.e., chronic followed by acute stress. These parameters were correlated with adrenal activity as judged from serum levels of corticosterone and catecholamine, respectively, as well as with serum levels of ACTH and glucose. Under all three conditions, we observed bilaterally asymmetric and stress-type-independent hypertrophy of whole adrenals, as well as adrenal cortices and medullas. Under acute and combined stress, adrenal hypertrophy was followed by increase of adrenal hormones in the blood serum. However, under chronic stress, both cortical and medullar activities as judged from low or unaltered levels of the respective hormones and glucose were compromised and disconnected from the input signal of ACTH. Since all of the studied adrenal activities could be restored by subsequent acute stress, it is concluded that chronic isolation can be viewed as partly maladaptive stress with characteristics resembling stress resistance rather than the stress exhaustion stage of the general adaptation syndrome.

scholarly journals 19-Hydroxy steroids in the aromatase reaction: Review on expression and potential functions

2021 ◽  
Author(s):  
Tatjana Abaffy ◽  
Hiroaki Matsunami
Keyword(s):  
Adrenal Glands ◽  
Ovarian Function ◽  
Scientific Evidence ◽  
Future Research ◽  
Analytical Sensitivity ◽  
Biological Processes ◽  
Search Terms ◽  
Pathological Conditions ◽  
Pubmed Database ◽  
The Brain

Abstract Scientific evidence related to the aromatase reaction in various biological processes spanning from mid-1960 is abundant, however, as our analytical sensitivity increases, a new look at the old chemical reaction is necessary. Here, we review an irreversible aromatase reaction from the substrate androstenedione. It proceeds in 3 consecutive steps. In the first two steps, 19-hydroxy steroids are produced. They can dissociate from the enzyme complex and either accumulate in tissues or enter the blood.In this review, we want to highlight the potential importance of these 19-hydroxy steroids in various physiological and pathological conditions. We focus primarily on 19-hydroxy steroids, and in particular on the 19-hydroxyandrostenedione produced by the incomplete aromatase reaction. Using a PubMed database and search terms aromatase reaction,19-hydroxylation of androgens and steroid measurements, we detail the chemistry of the aromatase reaction and list previous and current methods used to measure 19-hydroxy steroids. We present the evidence of the existence of 19-hydroxy steroids in the brain tissue, ovaries, testes, adrenal glands, prostate cancer and also during pregnancy and parturition and in Cushing’s disease. Based on the available literature, a potential involvement of 19-hydroxy steroids in the brain differentiation process, sperm motility, ovarian function, and hypertension is suggested and warrant future research.We hope that with the advancement of highly specific and sensitive analytical methods, future research into 19-hydroxy steroids will be encouraged, as much remains to be learned and discovered.

PHOTOPERIODIC MODULATION OF GONADOTROPHIN SECRETION IN CASTRATED JAPANESE QUAIL

1982 ◽  
Vol 92 (1) ◽  
pp. 73-83 ◽  
Author(s):  
H. F. URBANSKI ◽  
B. K. FOLLETT
Keyword(s):  
Japanese Quail ◽  
Plasma Levels ◽  
Time Course ◽  
Neural Mechanisms ◽  
Gonadal Steroids ◽  
Photoperiodic Control ◽  
Gonadotrophin Secretion ◽  
Lh Secretion ◽  
Sexually Mature ◽  
Short Days

Male Japanese quail were castrated when sexually immature and immediately exposed to one of the following stimulatory lighting regimes for 52 days: 11 h light: 13 h darkness/day (11L : 13D), 12L : 12D, 13L : 11D, 14L : 10D, 15L : 9D, 16L : 8D, 20L : 4D or 23L : 1D. One group was retained on short days (8L : 16D). Clearcut differences in the plasma levels of LH and FSH emerged between the various groups. Levels remained very low in castrated quail on 8L : 16D but were much greater in those on 14L : 10D, 15L : 9D, 16L : 8D, 20L : 4D and 23L : 1D, eventually becoming 15 to 20 times higher. Less pronounced castration responses developed on 13L : 11D, 12L : 12D or 11L : 13D. Alterations in photoperiod after day 52 caused an appropriate rise or fall in LH secretion. Photoperiodically induced suppressions were rapid, being highly significant within 4 days, but increases usually had a slower time course. When sexually mature quail (on 16L : 8D) were castrated and transferred to 8L : 16D they also exhibited a rapid suppression in LH secretion. Thus in quail, unlike some mammals, the photoperiodic control over gonadotrophin secretion is independent of the reproductive status of the animal at the time of castration. The results confirm the view that changes in sensitivity of the hypothalamo-pituitary axis to gonadal steroids are not a primary factor in the neural mechanisms underlying photoperiodism in quail.

The secretion of gonadotrophins, insulin and insulin-like growth factor 1 by Merino rams supplemented with different legume seeds

1996 ◽  
Vol 47 (6) ◽  
pp. 843 ◽  
Author(s):  
D Blache ◽  
DW Miller ◽  
JTB Milton ◽  
GB Martin
Keyword(s):  
Growth Factor ◽  
Chemical Constituents ◽  
Soybean Seed ◽  
Pulse Frequency ◽  
Insulin Like Growth Factor ◽  
Lupin Seed ◽  
Legume Seeds ◽  
Gonadotrophin Secretion ◽  
The Mean ◽  
The Brain

Supplementing mature rams with lupin seed (Lupinus angustifolius, a highly digestible source of energy and protein) increases gonadotrophin secretion within 5-10 days. When sheep receive a post-ruminal supplement of protein and energy equivalent to that in the lupin supplement, LH secretion is increased but not to the same extent as with lupin seed itself. This suggests that lupin seed contains a specific mixture of nutrients or an unknown component that exerts effects on the brain centres that control gonadotrophin secretion. This hypothesis was tested by comparing the responses to isonitrogenous and isoenergetic supplements of 3 legumes: lupins, cowpeas, and soybeans. Rams were fed the supplements for 10 days and blood was sampled every 20 min for 24 h on days -1, 5, and 10 relative to the start of supplementation. The plasma was assayed for LH, FSH, and the metabolic hormones insulin and insulin-like growth factor 1 (IGF-1). Both the cowpea and the lupin supplements increased LH pulse frequency and the mean concentrations of insulin and IGF-1 on days 5 and 10 compared with day -1 (P < 0.05). The soybean supplement did not affect LH pulse frequency or the concentrations of insulin or IGF-1. Only the cowpea supplement increased the mean concentration of FSH. The nutritional stimulation of the reproductive centres of the brain appears not to be specific to lupins, because the diet supplemented with cowpeas evoked similar responses. The lack of response to soybean seed suggests that the effects of diet on secretion of metabolic and gonadotrophic hormones are not due simply to the total energy and protein content of the diets, but to subtle differences in their chemical constituents.

scholarly journals Genesis of the ultradian rhythm of GH secretion: a new model unifying experimental observations in rats

1998 ◽  
Vol 275 (6) ◽  
pp. E1046-E1054 ◽  
Author(s):  
Clemens Wagner ◽  
S. Roy Caplan ◽  
Gloria S. Tannenbaum
Keyword(s):  
Time Course ◽  
Male Rat ◽  
Peripheral Tissues ◽  
Feedback Mechanisms ◽  
Gh Secretion ◽  
Metabolic Functions ◽  
Neuroendocrine Axis ◽  
Two Peaks ◽  
The Brain ◽  
Gh Receptors

Growth hormone (GH) induces growth in animals and humans and also has important metabolic functions. The GH neuroendocrine axis consists of a signaling cascade from the hypothalamus to the pituitary, the liver, and peripheral tissues, including two major feedback mechanisms. GH is secreted from the pituitary into the circulating blood according to the effect on the somatotrophs of two hypothalamic peptides, GH-releasing hormone (GHRH) and its antagonist, somatostatin (SRIF). The typical GH profile in the male rat shows secretory episodes every 3.3 h, which are subdivided into two peaks. Focusing on the mechanisms for generation of this ultradian GH rhythm, we simulated the time course of GH secretion under a variety of conditions. The model that we propose is based on feedback of GH on its own release mediated both by GH receptors on SRIF neurons in the brain and by a delayed SRIF release into both the brain and portal blood. SRIF, with a resultant periodicity of 3.3 h, affects both the somatotroph cells in the pituitary and the GHRH neurons in the hypothalamus. The secretion of GHRH is postulated to occur in an ∼1-h rhythm modulated by the level of SRIF in the hypothalamus. The model predicts a possible mechanism for the feminization of the male GH rhythm by sex steroids and vice versa, and suggests experiments that might reveal the proposed intrinsic 1-h GHRH rhythm.

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