CHOLINERGIC INFLUENCES ON HYPOTHALAMIC-PITUITARY-ADRENOCORTICAL ACTIVITY OF STRESSED RATS: AN APPROACH UTILIZING CHOLINE DEFICIENT DIETS

1978 ◽  
Vol 89 (4) ◽  
pp. 737-743 ◽  
Author(s):  
N. Sithichoke ◽  
L. J. Malasanos ◽  
S. F. Marotta
Keyword(s):  
Drinking Water ◽  
Cholinergic System ◽  
Adrenal Glands ◽  
Plasma Corticosterone ◽  
Male Rats ◽  
Cholinergic Activity ◽  
Deficient Diet ◽  
Adrenocortical Activity ◽  
Hpa Response

ABSTRACT Male rats were placed on choline (Ch) deficient diets for 3 to 14 days, without and with Ch (normal and large doses) supplemented in the drinking water, to determine whether altering the availability of Ch would affect the cholinergic system in relation to the latter's role in modulating the hypothalamic-pituitary-adrenocortical (HPA) system of non-stressed and stressed animals. The results indicate that the basal nonstressed activity of the HPA system, as assessed by adrenal and plasma corticosterone concentrations, was not affected by placing the animals on these diets for as long as 14 days. Furthermore, the in vitro production of corticosterone by these adrenal glands, in the presence or absence of adrenocorticotrophin, was similar to those observed in animals on a regular rat diet; however, the HPA responses to auditory (100 db) stress, and to a lesser extent hypercapnic (9 % CO2) stress, were impaired on the Ch deficient diet (14 days), and these responses were partially corrected by supplementing the diet with Ch in the drinking water. Thus, the data suggest that altering the dietary intake of Ch may affect cholinergic activity, which in turn affects the HPA response to stressors.

CHOLINERGIC INFLUENCES ON HYPOTHALAMIC-PITUITARY-ADRENOCORTICAL ACTIVITY OF STRESSED RATS: AN APPROACH UTILIZING AGONISTS AND ANTAGONISTS

1978 ◽  
Vol 89 (4) ◽  
pp. 726-736 ◽  
Author(s):  
N. Sithichoke ◽  
S. F. Marotta
Keyword(s):  
Stressed State ◽  
Cholinergic System ◽  
Plasma Corticosterone ◽  
Cholinergic Receptors ◽  
Male Rats ◽  
Central Effects ◽  
Adrenocortical Activity ◽  
Hpa Response ◽  
Stimulation Of ◽  
Auditory Stress

ABSTRACT Cholinergic involvement in the regulation of the hypothalamic-pituitary-adrenocortical (HPA) system of male rats was evaluated using muscarinic (atropine and methacholine) and nicotine (mecamylamine and nicotine) agents, which were selected for their specificity on cholinergic receptors (ChR). They were administered either intracerebroventricularly (icv) to produce central effects, or ip to produce both central and peripheral effects, prior to subjecting the animals to either auditory or hypercapnic stress for 1 h. Plasma corticosterone was used as an index of HPA activity. The results suggest that central muscarinic ChR are involved in inhibiting HPA activity in both non-stressed and stressed animals, whereas central nicotinic ChR are excitatory during stress but inactive in the non-stressed state. Stimulation of peripheral nicotinic ChR appeared to potentiate the HPA response to hypercapnia, and to inhibit the central excitatory nicotinic ChR when the latter were activated in non-stressed and auditory stressed rats. These data suggest that during auditory stress the HPA system is more dependent upon the cholinergic system for its activation than during non-stressed and hypercapnic states.

Thermogenic and metabolic consequences of thyroid hormone treatment in brown and white adipose tissue

1985 ◽  
Vol 5 (2) ◽  
pp. 175-184 ◽  
Author(s):  
Christine M. Williams ◽  
Rodney Ellis
Keyword(s):  
Drinking Water ◽  
Adipose Tissue ◽  
White Adipose Tissue ◽  
Hormone Treatment ◽  
Male Rats ◽  
Fat Pad ◽  
Brown Adipose ◽  
Glucose Incorporation ◽  
White Fat

Male rats were treated with triiodothyronine in the drinking water for 12 days. In vitro rates of isoprenaline stimulated lipolysis were significantly greater in brown but not white adipose tissue. Rates of [14C]glucose incorporation into triacylglycerols were significantly reduced in BAT (brown adipose tissue) and WAT (white adipose tissue) under basal and isoprenaline stimulated conditions, in a second experiment, hyperthyroid animals showed impaired weight gain, despite increased food intake during t9 days' treatment. Energy expenditure on days 5 and 12, and BAT core temperature differences (TBAT – TCORE) on day 19, were significantly greater than in control animals. Epididymal white fat pad weight was reduced and interscapular brown fat pad weight increased by triiodothyronine treatment.

Effect of brain monoamines on the secretion of adrenocorticotrophic hormone

1982 ◽  
Vol 101 (2) ◽  
pp. 180-186 ◽  
Author(s):  
Alka Amar ◽  
S. Mandal ◽  
A. K. Sanyal
Keyword(s):  
Dopaminergic Neurons ◽  
Adrenal Glands ◽  
Plasma Corticosterone ◽  
Albino Rats ◽  
Adrenocorticotrophic Hormone ◽  
Brain Monoamines ◽  
Acth Secretion ◽  
Acute Increase

Abstract. The role of brain monoamines (5-HT, NA and DA) in the secretion of adrenocorticotrophic hormone (ACTH) was studied in view of contradictory reports. Plasma corticosterone levels and the rate of synthesis of corticosterone in vitro by the adrenal gland were estimated in albino rats and have been taken as the index of ACTH activity. These estimations were done in unstressed and stressed, and in untreated and treated rats. Drugs were administered intracerebroventricularly to the rats to cause selective degeneration of tryptaminergic, noradrenergic or dopaminergic neurons. The results show that plasma corticosterone levels and the rate of synthesis of corticosterone were significantly decreased after selective degeneration of tryptaminergic neurons in unstressed rats. After selective degeneration of either tryptaminergic or noradrenergic neurons, the acute increase in the plasma corticosterone levels and rate of synthesis of corticosterone in vitro by adrenal glands in stressed rats were significantly inhibited. These results have been interpreted to suggest that the central tonic control on adrenal glands may be 5-HT mediated and that during stress ACTH secretion may be both 5-HT and NA mediated. DA does not seem to have significant role in the regulation of ACTH secretion.

ANALYSIS OF THE INHIBITION OF THE ACTH RELEASE BY HYPOTHALAMIC IMPLANTS OF ATROPINE

1973 ◽  
Vol 73 (4) ◽  
pp. 651-659 ◽  
Author(s):  
J. Kaplanski ◽  
P. G. Smelik
Keyword(s):  
Adrenal Glands ◽  
Plasma Corticosterone ◽  
Corticosterone Concentration ◽  
Hypothalamic Region ◽  
Adrenal System ◽  
Cholinergic Synapses ◽  
Adrenocortical Responses ◽  
Acth Release

ABSTRACT The effect of anterior hypothalamic atropine implants on the secretion of corticotrophin in the rat, as indicated by the corticosteroid production by adrenal glands incubated in vitro and/or by the plasma corticosterone concentration, was studied. It was found that atropine implants markedly inhibit the adrenocortical responses evoked by all the stress stimuli tested, except for that to a CRF preparation. The onset of the blockade was very fast; the duration of the inhibition lasted for about 2 h. Smaller amounts of atropine (2×15 μg) were also effective when implanted bilaterally into the anterior hypothalamic region. It is concluded that cholinergic synapses in the hypothalamus may be involved in the activation of the pituitary-adrenal system after stressful stimuli.

THYROTROPHIN RELEASING FACTOR (TRF) IN CEREBROSPINAL FLUID OF THE 3RD VENTRICLE OF RAT

1974 ◽  
Vol 76 (2) ◽  
pp. 209-213 ◽  
Author(s):  
K. M. Knigge ◽  
S. A. Joseph
Keyword(s):  
Cerebrospinal Fluid ◽  
Drinking Water ◽  
Median Eminence ◽  
Cold Exposure ◽  
Male Rats ◽  
Assay Method ◽  
Normal Male ◽  
3Rd Ventricle ◽  
Pooled Samples

ABSTRACT The concentration of TRF in cerebrospinal fluid (CSF) of the 3rd ventricle and content of TRF in median eminence of the rat was examined. CSF (0.3–0.5 μl per animal) was collected from the 3rd ventricle by a microcannula technique and pooled samples from 10–15 animals were examined for TRF using an in vitro pituitary assay method. TRF concentration in 3rd ventricle CSF of normal male rats was 18.5 ± 4.2 pg/μl; median eminence contained 115 ± 12 pg. Cold exposure (4°C) for 16–18 h and thyroxine treatment (2.5 μg/day) for 5 days markedly reduced TRF concentration in CSF and content in the median eminence. Treatment with the anti-thyroid drug methimazole (0.01 % in the drinking water) for 5 days did not notably affect TRF in CSF or median eminence.

EFFECTS OF TESTOSTERONE ON PITUITARY CORTICOTROPHIN AND ADRENAL STEROID SECRETION IN MALE AND FEMALE RATS

1963 ◽  
Vol 43 (4) ◽  
pp. 601-608 ◽  
Author(s):  
Julian I. Kitay
Keyword(s):  
Plasma Corticosterone ◽  
Female Rats ◽  
Male Rats ◽  
Intact Male ◽  
Male And Female ◽  
Adrenal Steroid ◽  
Adrenal Steroidogenesis ◽  
Male And Female Rats

ABSTRACT Administration of a depot testosterone preparation to male and female rats resulted in no change in body or pituitary weight in either sex. Pituitary corticotrophin content was unaltered in male animals but was reduced in females. Adrenal weights and adrenal RNA and DNA contents were decreased in both sexes. Plasma corticosterone concentrations were unaffected in males but were reduced in female rats after stress or corticotrophin injection. Hepatic reduction of ring A in vitro and biological half-life of corticosterone in vivo were unchanged in male animals but impaired in females. Testosterone administration to intact male rats significantly increased adrenal steroidogenesis measured in vitro. A significant decrease in steroid production was found in intact females but increased steroidogenesis was observed in adrenals from testosterone-treated oophorectomized animals. No effect was obtained following addition of testosterone directly in vitro. The data suggest that testosterone leads both to diminution of corticotrophin secretion and enhancement of adrenal steroid secretory capacity. In intact female rats, these effects are complicated by suppression of oestrogen secretion, the effects of which have been reported previously.

HYPOTHALAMIC LUTEINIZING HORMONE RELEASING FACTOR AND CORTICOTROPHIN RELEASING ACTIVITY IN RELATION TO PITUITARY AND PLASMA HORMONE LEVELS IN MALE AND FEMALE RATS

1977 ◽  
Vol 72 (2) ◽  
pp. 195-210 ◽  
Author(s):  
SHARON A. CHIAPPA ◽  
G. FINK
Keyword(s):  
Plasma Corticosterone ◽  
Female Rats ◽  
Male Rats ◽  
Male And Female ◽  
Male And Female Rats ◽  
Protein Binding Assay ◽  
Female Wistar Rats ◽  
Competitive Protein Binding Assay ◽  
Animal House

SUMMARY Hypothalamic corticotrophin releasing (CR) activity and LH-releasing factor (RF) content, and pituitary and plasma LH, FSH and ACTH were measured in adult male and female Wistar rats maintained under 14 h light per day. Hypothalamic LH-RF and pituitary and plasma hormones were estimated by radioimmunoassay while CR-activity was assessed by the amount of ACTH released from hemipituitaries in vitro. Two experiments were carried out on male animals. In the first, some of the animals were kept in a room, distant from the animal house, in which the lighting was reversed with respect to the external environment. In animals exposed to the reversed lighting régime, hypothalamic LH-RF content and pituitary gonadotrophin concentrations were significantly lower than the values in male rats kept in the animal house where they were in close proximity to female rats. In the second experiment, which was carried out on animals which had all been kept in the animal house, there were no significant differences between the LH-RF contents measured at 3–4 h intervals throughout the day. Pituitary LH and FSH contents, but not concentrations, were significantly increased at 12.00 h. There was little difference between the experiments in CR-activity, plasma ACTH concentrations and profiles of pituitary ACTH content and concentration. As expected there was a diurnal rhythm in plasma corticosterone concentrations (determined by competitive protein-binding assay) with the peak occurring between 15.00 and 18.00 h. The profiles of plasma and pituitary ACTH were similar to that of plasma corticosterone. Corticotrophin releasing activity dropped significantly between 12.00 and 16.00 h, but remained steady at the other times.

THE EFFECT OF PIG PITUITARY ACTH FRACTIONS ON DIFFERENT PARAMETERS OF ADRENOCORTICAL ACTIVITY

1963 ◽  
Vol 41 (6) ◽  
pp. 1455-1467 ◽  
Author(s):  
E. de Jager ◽  
J. D. H. Homan ◽  
D. de Wied
Keyword(s):  
Plasma Corticosterone ◽  
Buffer System ◽  
Adrenocortical Activity ◽  
In Vivo Assays ◽  
In Vitro Technique ◽  
Separate Fraction ◽  
Hypophysectomized Rats ◽  
Assay Methods

Purified unhydrolyzed corticotrophin was separated into five fractions by chromatography on a column of carboxymethyl cellulose, using pyridine – acetic acid as a buffer system. These fractions were biologically assayed by means of the in vitro technique of Saffran and Schally, the adrenal ascorbic acid depletion test of Sayers et al., and an assay based on the increase of plasma corticosterone levels in hypophysectomized rats. In the in vivo assays both the intravenous and subcutaneous routes of injection were applied.The principal aim of this study was to investigate for each separate fraction the extent to which the potencies according to the Sayers test correspond with the potencies obtained by the plasma corticosterone method. When comparing results found after identical routes of injection, a fair agreement was observed for those fractions showing electrophoretic relationship and together accounting for the major part of the biological activity of the starting material. However, the minor fractions showed significant differences.These findings are discussed together with the results of the classical assay methods and their deviations from data reported in the literature.

Adrenocortical function in response to myocardial necrosis in exercise-trained rats

1978 ◽  
Vol 44 (1) ◽  
pp. 104-108 ◽  
Author(s):  
J. A. Severson ◽  
R. D. Fell ◽  
D. R. Griffith
Keyword(s):  
Myocardial Necrosis ◽  
Plasma Corticosterone ◽  
Treadmill Running ◽  
Male Rats ◽  
Adrenocortical Function ◽  
Subcutaneous Injections ◽  
Corticosterone Secretion ◽  
Virgin Male ◽  
And Control

Plasma corticosterone concentrations and in vitro adrenal secretion of corticosterone was determined in exercise-trained rats. Virgin, male rats, 100 days of age, were trained for an 11-wk period by treadmill running. Following the training program, rats were subjected to two subcutaneous injections of l-isoproterenol 24 h apart and killed 24 h after the second injection. All exercise-trained rats survived isoproterenol treatment, while 44% of the control rats died. Plasma corticosterone concentrations were elevated only in exercise-trained rats treated with isoproterenol. Control rats treated with isoproterenol had plasma corticosterone concentrations similar to that in control and exercise-treated rats given placebo injections. Exercise training reduced adrenocortical responsiveness to ACTH in vitro, but isoproterenol treatment increased in vitro responsiveness to ACTH in exercise-trained and control rats. Total unstimulated corticosterone secretion rates in vitro were similar. The reason for better rat survival in exercise-trained rats is unknown; however, improved energy metabolism, depressed aldosterone secretion, or both are suggested as reasons for the better survival of exercise-trained rats.

EFFECTS OF NORETHANDROLONE ON CORTISONE-INDUCED PITUITARY-ADRENAL SUPPRESSION IN THE RAT

1966 ◽  
Vol 52 (1) ◽  
pp. 25-29 ◽  
Author(s):  
Julian I. Kitay ◽  
M. D. Coyne
Keyword(s):  
Combined Therapy ◽  
Test Dose ◽  
Hepatic Metabolism ◽  
Plasma Corticosterone ◽  
Male Rats ◽  
Concomitant Treatment ◽  
Response To Stress ◽  
Corticosterone Response ◽  
Adrenal Corticosterone

ABSTRACT Norethandrolone administered to castrated male rats stimulated adrenal corticosterone production evaluated in vitro and increased pituitary content of corticotrophin (ACTH). Hepatic metabolism of corticosterone in vitro was unchanged. Concomitant treatment with norethandrolone and cortisone resulted in significantly greater adrenal corticosterone production in vitro compared to that obtained after cortisone treatment alone. Combined therapy also enhanced the plasma corticosterone response to a test dose of ACTH. No improvement was noted in the response to stress, offering no substantiation to the hypothesis that norethandrolone is of value in overcoming cortisone-induced depression of pituitary ACTH release.

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