Effect of adrenalectomy on the regulation of the secretion of gonadotrophins and prolactin in the lactating rat

1983 ◽  
Vol 98 (2) ◽  
pp. 227-232 ◽  
Author(s):  
P. van der Schoot ◽  
W. J. de Greef
Keyword(s):  
Plasma Levels ◽  
Inhibitory Action ◽  
Adrenal Glands ◽  
Marked Effect ◽  
Plasma Concentrations ◽  
Inhibitory Effect ◽  
Blood Levels ◽  
Adrenal Hormones ◽  
Adrenocortical Hormones ◽  
Adrenalectomized Rats

The suckling stimulus exerts an inhibitory action on the release of gonadotrophins during lactation. The possible involvement of the adrenal glands in this process was examined by studying the plasma levels of gonadotrophins in lactating rats ovariectomized on the day after parturition. It appeared that the suppression, throughout suckling, of the rise in levels of gonadotrophins in blood after ovariectomy occurred to the same extent in adrenalectomized and in sham-operated animals. It thus seems unlikely that adrenocortical hormones, albeit secreted in larger quantities during lactation, exert an inhibitory effect on the release of gonadotrophins. Adrenalectomy had a marked effect on the plasma concentrations of prolactin during the second half of lactation. Whereas plasma concentrations of prolactin in the first half of lactation were similar in adrenalectomized and sham-operated rats, the concentrations in adrenalectomized rats did not undergo the reduction found in sham-operated rats. Adrenal hormones may thus be involved in the reduction of blood levels of prolactin observed in rats and in other mammals as lactation progresses.

INHIBITORY ACTION OF CORTISONE ON TESTOSTERONE-INDUCED GROWTH OF THE VENTRAL PROSTATE, THE DORSOLATERAL PROSTATE, THE COAGULATING GLANDS AND THE SEMINAL VESICLES IN CASTRATED ADRENALECTOMIZED RATS

1972 ◽  
Vol 69 (2) ◽  
pp. 359-368 ◽  
Author(s):  
Lars-Eric Tisell
Keyword(s):  
Inhibitory Action ◽  
Testosterone Propionate ◽  
Reproductive Organs ◽  
Inhibitory Effect ◽  
Seminal Vesicles ◽  
Male Rats ◽  
Ventral Prostate ◽  
Adrenal Steroids ◽  
Androgenic Effect ◽  
Adrenalectomized Rats

ABSTRACT The weight and histology of the ventral and dorsolateral prostate, the coagulating glands and the seminal vesicles were studied in castrated non-adrenalectomized male rats after sixteen days of daily injections of testosterone propionate and in castrated adrenalectomized rats after daily injections of testosterone propionate alone or in combination with cortisone. Testosterone propionate was given in daily doses of 0.020 mg and cortisone in daily doses of 1 mg, 3 mg or 9 mg. Testosterone alone induced a less pronounced growth of the dorsolateral prostate, the coagulating glands and the seminal vesicles in castrated non-adrenalectomized than in castrated adrenalectomized rats, suggesting an inhibitory effect of adrenal steroids on the action of testosterone. Cortisone which has a weak androgenic effect when given alone, partially counteracted the testosterone induced growth of the accessory reproductive organs in castrated adrenalectomized rats.

Action of somatostatin on stomach, pancreas, gastric mucosal blood flow, and hormones

1983 ◽  
Vol 244 (1) ◽  
pp. G40-G45 ◽  
Author(s):  
T. M. Lin ◽  
D. C. Evans ◽  
C. J. Shaar ◽  
M. A. Root
Keyword(s):  
Blood Flow ◽  
Pancreatic Secretion ◽  
Inhibitory Action ◽  
Plasma Concentrations ◽  
Mucosal Blood Flow ◽  
Gastric Mucosal Blood Flow ◽  
Inhibitory Effect ◽  
Low Doses ◽  
Primary Mechanism ◽  
Basal Plasma

In dogs gastric secretion induced by tetragastrin and pancreatic secretion induced by secretin and/or cholecystokinin were inhibited by somatostatin at doses of 0.06-1 microgram X kg-1 X h-1 and 0.06-1 microgram X kg-1 X 0.5 h-1, respectively. Inhibition was a linear function of the logarithm of dose. Basal and 2-deoxy-D-glucose-induced gastric acid secretion was also significantly inhibited by low doses of somatostatin. Results in this study differ from those reported previously by clarifying the action of somatostatin as follows. 1) The inhibitory effect of somatostatin on pancreatic protein secretion was significantly greater than that on water and bicarbonate production. Somatostatin was more effective on cholecystokinin- than secretin-induced pancreatic secretion. 2) Although gastric mucosal blood flow (MBF) was affected by somatostatin, the reduction of MBF was not the primary mechanism responsible for its inhibitory action. 3) The low doses of somatostatin used in this study significantly inhibited gastric and pancreatic secretion without affecting the basal plasma concentrations of insulin, glucagon, growth hormone, gastrin, or secretin in the dogs, suggesting that the inhibitory action was not mediated by changes or reduction in plasma concentration of these hormones.

scholarly journals The effect of chitosan on limitation of growth and development of some pathogenic fungi for ornamental plants

2013 ◽  
Vol 54 (1) ◽  
pp. 17-29 ◽  
Author(s):  
Alicja Saniewska
Keyword(s):  
Fusarium Oxysporum ◽  
Inhibitory Action ◽  
Marked Effect ◽  
Ornamental Plants ◽  
Pathogenic Fungi ◽  
Inhibitory Effect ◽  
Crab Shell ◽  
Necrotic Spots ◽  
Tulip Bulbs

The inhibitory effect of crab-shell chitosan, medium (200-800 cps) and high molecular weight ( 800-2000 cps) (purchased from Sigma-Aldrich Chemicals) toward <i>Alternaria alternata, Botrytis tulipae, Fiisarium oxysporum</i> f. sp. <i>callistephi, Fusarium oxysporum</i> f. sp. <i>tulipae, Phoma narcissi</i> and <i> Phoma poolensis</i> was evaluated <i>in vitro</i> and in <i>vivo</i>. The chitosan evidently inhibited in vitro growth of all tested pathogens, with a marked effect at higher concentrations above 200 μg/cm<sup>3</sup>. Chitosan at a concentration of 1,25; 2,5 and 5,0 mg/cm<sup>3</sup> didn't have inhibitory action in appearance of fungi growth on naturally contaminated <i>Callistephus chinensis</i> seeds. At the same concentrations, chitosan applied as bulb scales dressing of <i>Hymenocallis narcissiflora</i> bulbs, before inoculation or after inoculation with <i>Phoma narcissi</i>, inhibited the development of necrotic spots on scales. Chitosan used preventively or curatively at a concentrations of 1,25; 2,5 and 5,0 mg/cm<sup>3</sup> indicated inhibitory effect on development of <i>Fusarium oxysporum</i> f. sp. <i>tulipae</i> on tulip bulbs. Chitosan at a concentration of 10 mg/cm<sup>3</sup> applied preventively (first spray 12th June) was very effective in the control of <i>Puccinia antirrhini</i> on snapdragon in the field. The strongest inhibitory effect was observed on snapdragon treated 8 times at week intervals.

Effect of adrenalectomy on the regulation of ovarian function during lactation in the rat

1983 ◽  
Vol 98 (2) ◽  
pp. 233-240 ◽  
Author(s):  
W. J. de Greef ◽  
P. van der Schoot
Keyword(s):  
Adrenal Glands ◽  
Ovarian Function ◽  
Post Partum ◽  
Acute Effect ◽  
Prolactin Secretion ◽  
Daily Treatment ◽  
Corpora Lutea ◽  
Plasma Prolactin ◽  
Adrenal Hormones ◽  
Adrenalectomized Rats

Corpora lutea formed after post-partum ovulation in the rat become functionally active under the influence of prolactin released as a result of suckling. During this period of luteal activity (lactational pseudopregnancy) ovulations do not occur. Despite continued suckling plasma prolactin declines gradually during lactation but this gradual decrease was not observed when adrenalectomy was performed on day 2 of lactation. The prolongation of lactational pseudopregnancy after adrenalectomy is probably associated with this observation. Daily treatment of adrenalectomized lactating rats with 5 mg corticosterone acetate, but not with 1·5 mg, reduced the duration of lactational pseudopregnancy to that of controls. Removal of litters of five pups on day 13 of lactation was followed by resumption of ovulation 3 days later in control animals. However, in adrenalectomized rats the interval between removal of the five-pup litter and the next ovulation was prolonged to 10 or more days because of the persistence of luteal activity. This prolonged interval in adrenalectomized rats was not caused by an acute effect of the absence of adrenal hormones since it was not observed in rats which had been adrenalectomized 3 days before removal of the litter. Furthermore, the increase in the interval between removal of the five-pup litter and resumption of ovulation was also not due to the absence of the main glucocorticoid in the rat, since daily treatment with corticosterone from the day of adrenalectomy failed to prevent the occurrence of the long delay. Adrenal transplants could, however, prevent the effect induced by adrenalectomy. Since the medulla of these transplants had become necrotic, it seems that factors of adrenocortical, but not of adrenal medullary origin, are important in preventing the occurrence of the prolonged interval. It is concluded that the adrenal glands affect the regulation of prolactin secretion during lactation and, as a consequence, are important in establishing the duration of the anovulatory state during lactation.

CORRELATION OF REVERSE-T3 AND 3,3′-T2 (T2′) PLASMA CONCENTRATIONS UNDER PHYSIOLOGICAL AND EXPERIMENTAL CONDITIONS IN MAN

1978 ◽  
Vol 89 (4) ◽  
pp. 679-686 ◽  
Author(s):  
M. Hüfner ◽  
M. Grussendorf
Keyword(s):  
Plasma Levels ◽  
Plasma Concentrations ◽  
Blood Levels ◽  
Experimental Conditions ◽  
Reverse T3 ◽  
Physiological Conditions ◽  
Minor Degree ◽  
A Minor ◽  
Therapeutic Doses ◽  
Normal Adults

ABSTRACT T2′ plasma levels are measured under different conditions and correlated to the respective rT3 concentrations. Specific RIAs for T2′ and rT3 are used. Pharmacological doses of T3 cause an increase of plasma T2′; if T3 or T4 doses are administered to an athyroid patient which cause a similar level of plasma T3 the increase of T2′ is much larger during T4 treatment. Cord blood levels of T2′ are 2–3-fold higher than in normal adults whereas rT3 concentrations are about 10 times higher than normal. After birth rT3 and T2′ levels decrease in about a parallel manner. After a bolus iv injection of 500 μg rT3, T2′ starts to increase as early as 2 min after injection. PTU in therapeutic doses causes a rapid increase of plasma rT3 with a maximum 4 h after ingestion. A dose of 150 mg PTU causes a maximum of about 100% above baseline. T2′ also increases but to a lesser degree (about 50 % above baseline). We conclude that rT3 is the most important precursor of T2′ whereas T3 contributes only to a minor degree to the total T2′ production under physiological conditions.

Variations in plasma motilin, somatostatin, and pancreatic polypeptide concentrations and the interdigestive myoelectric complex in dog

1985 ◽  
Vol 63 (12) ◽  
pp. 1495-1500 ◽  
Author(s):  
P. Poitras ◽  
M. Lemoyne ◽  
D. Tasse ◽  
L. Trudel ◽  
T. Y. Yamda ◽  
...  
Keyword(s):  
Pancreatic Polypeptide ◽  
Plasma Levels ◽  
Intestinal Motility ◽  
Plasma Concentrations ◽  
Statistical Correlation ◽  
Significant Rise ◽  
Phase Iii ◽  
Blood Levels ◽  
Plasma Motilin ◽  
Related Increase

We have looked at the plasma concentrations of motilin, pancreatic polypeptide (PP), and somatostatin (STS) during the various phases of the interdigestive motor complex (IDMC) in dogs. As expected, motilin cyclical increase was always associated with the phase III of the IDMC. Statistical analysis of PP variations revealed a significant rise 10 min before duodenal phase III; however, in individual animals, this relationship was inconsistent. Although a dose-related increase in PP blood levels was induced by administration of synthetic canine motilin (0–200 ng kg−1 iv), fasting plasma levels of PP were not correlated with the concentrations of circulating endogenous motilin. After truncal vagotomy, while motilin release and the intestinal motility pattern remained unaltered, the phase III associated cyclical increases of PP disappeared. Infusion of physiological amounts of PP (1 μg kg−1 h−1 for 3 h) mimicking the postprandial release failed to reproduce a fed pattern type of intestinal motility and of motilin secretion. No statistical correlation could be established between STS plasma levels and the motor activity of the intestine. STS plasma levels were not correlated with circulating concentrations of motilin and the exogenous administration of physiological doses of synthetic canine motilin failed to modify STS plasma levels. Morphine (200 μg kg−1 iv) stimulated only the release of motilin. These data suggest that the role played by circulating concentrations of PP and STS in the control of the IDMC in dog is at most minimal.

EFFECT OF α-MSH ON PLASMA LEVELS OF LH, FSH, PROGESTERONE AND CORTISOL DURING THE CORPUS LUTEUM PHASE OF THE MENSTRUAL CYCLE

1976 ◽  
Vol 81 (1) ◽  
pp. 243-251 ◽  
Author(s):  
B. Runnebaum ◽  
J. Heep ◽  
W. Geiger ◽  
P. Vecsei ◽  
J. Andor
Keyword(s):  
Menstrual Cycle ◽  
Corpus Luteum ◽  
Plasma Levels ◽  
Plasma Cortisol ◽  
Plasma Concentrations ◽  
Fold Increase ◽  
Blood Levels ◽  
Peripheral Plasma ◽  
Intravenous Infusions ◽  
Dose Dependent

ABSTRACT In healthy women (21–28 years) the influence of synthetic α-MSH upon the peripheral plasma levels of LH, FSH, progesterone and cortisol was determined during the corpus luteum phase of the menstrual cycle. As controls 3 women were given 6 intravenous infusions of 250 ml NaCl; 4 women received a total of 18 intravenous infusions of 5–20 mg α-MSH from 9.00 to 11.00 a. m. on the 5th and 7th hyperthermic day of the menstrual cycle. The blood levels of the hormones were usually followed for 24 h, and in two cases for 48 h. During and after the control as well as the experimental infusions with 5–20 mg α-MSH, no significant changes in the plasma concentrations of LH, FSH and progesterone were found. The cortisol concentrations, however, showed on the average a 2-fold increase over the initial values during the infusion of 5 mg and 10 mg α-MSH. During the control infusions they were not enhanced. One experiment was conducted with 20 mg α-MSH. The increase in the plasma cortisol levels following α-MSH administration generally seemed to be dose dependent, but statistically no significant differences regarding the increase in cortisol level could be detected between the 5 mg and 10 mg doses.

scholarly journals Inhibition of Efavirenz Metabolism by Sertraline and Nortriptyline and Their Effect on Efavirenz Plasma Concentrations

2015 ◽  
Vol 60 (2) ◽  
pp. 1022-1028 ◽  
Author(s):  
Virginia Melis ◽  
Iris Usach ◽  
Patricia Gandía ◽  
José-Esteban Peris
Keyword(s):  
Plasma Levels ◽  
Formation Rate ◽  
Plasma Concentrations ◽  
Pharmacokinetic Interaction ◽  
Transcriptase Inhibitor ◽  
Inhibitory Effect ◽  
Pharmacokinetic Parameters ◽  
Hepatic Microsomes

ABSTRACTBetween 22 and 45% of HIV-positive subjects are likely to report symptoms of depression. Considering this background, a potential pharmacokinetic interaction between the nonnucleoside reverse transcriptase inhibitor efavirenz (EFV) and two antidepressants, sertraline (SRT) and nortriptyline (NT), was studied. Rats were administered EFV alone or together with the antidepressants, and changes in the plasma levels and pharmacokinetic parameters of EFV were analyzed. Additionalin vitroexperiments with rat and human hepatic microsomes were carried out to evaluate the inhibitory effect of SRT and NT on EFV metabolism by determining the formation rate of the major EFV metabolite (8-OH-EFV).In vivostudies showed similar increases in the plasma levels of EFV when it was coadministered with SRT or NT. However, the studies using rat hepatic microsomes showed a more potent inhibitory effect of NT than of SRT on the metabolism of EFV, with values for the 50% inhibition constant (IC50) and inhibitory constant (Ki) for NT about 9-fold lower than those for SRT. An equation was deduced that explains the similarin vivoeffects of SRT and NT in spite of the differentin vitroperformance data. Using human hepatic microsomes, the strongest inhibitory effect was observed with SRT. In summary, pharmacokinetic interactions between EFV, SRT, and NT, associated with the inhibition of hepatic metabolism of EFV, have been detected in rats. Both antidepressants also inhibit EFV metabolism in human hepatic microsomes, but additionalin vivostudies in humans are required to evaluate the clinical implication of this interaction.

Effect of Adrenocorticotropin (ACTH) upon the Drug Response of Intact and Adrenalectomized Rats

1973 ◽  
Vol 51 (3) ◽  
pp. 169-174 ◽  
Author(s):  
S. Szabo ◽  
P. Kourounakis ◽  
H. Selye
Keyword(s):  
Plasma Levels ◽  
Drug Toxicity ◽  
Drug Response ◽  
Female Rats ◽  
Blood Levels ◽  
Prophylactic Effect ◽  
Intact Female ◽  
Adrenalectomized Rats

In intact female rats, pretreatment with crystalline ACTH for at least 4 days reduces zoxazolamine paralysis and diminishes the toxicity of aniline, N-methylaniline, and acetanilide. The corticotropic hormone increases the aggravation of drug toxicity by adrenalectomy. Corticosterone also reduces zoxazolamine paralysis; its action (when given alone or in combination with ACTH) is evident both in intact and in adrenalectomized animals. The prophylactic effect of ACTH against zoxazolamine is not associated with decreased plasma levels of the drug. Hence, ACTH and corticosterone act syntoxically in that rats pretreated with these hormones tolerate high blood levels of drugs without exhibiting signs of poisoning.

Dopamine 3-sulfate inhibits aldosterone secretion in cultured bovine adrenal cells

1984 ◽  
Vol 247 (4) ◽  
pp. E431-E435 ◽  
Author(s):  
K. Racz ◽  
N. T. Buu ◽  
O. Kuchel ◽  
A. De Lean
Keyword(s):  
Angiotensin Ii ◽  
Inhibitory Action ◽  
Adrenal Glands ◽  
Fold Increase ◽  
Inhibitory Effect ◽  
Ang Ii ◽  
Aldosterone Secretion ◽  
Adrenal Cells ◽  
Bovine Plasma

It has been demonstrated that dopamine inhibits the aldosterone (Aldo) secretion in bovine adrenal cells in vitro. Because the majority of the total circulating dopamine (DA) in bovine plasma (72%) is present in sulfoconjugated form (6.8 +/- 3.4 pmol/ml) and free DA, DA sulfate, and phenolsulfotransferase (PST) activity can be found in the bovine adrenal cortex, we examined whether the inhibitory action of free DA on angiotensin II- (ANG II) stimulated Aldo secretion by cultured bovine adrenal cells can also be reproduced by sulfoconjugated DA analogues. Cells from the bovine adrenal glands cultured for 3 days before testing responded to 10(-8) M ANG II stimulation by a 10- to 12-fold increase in Aldo output. This stimulatory effect was partially inhibited by the addition of free DA and DA 3-sulfate, whereas DA 4-sulfate was inactive. Both free DA and DA 3-sulfate produced their maximal inhibitory effect at a concentration of 100 microM, with a decrease in Aldo secretion by 61% (free DA) and 44% (DA 3-sulfate). The slightly different inhibition curves for DA and for DA 3-sulfate on Aldo secretion cannot be explained by liberation of free DA through hydrolytic processes because less than 1% free DA was detected after the incubation of the cells with sulfoconjugated DA. These in vitro findings suggest that DA 3-sulfate may be effective in complementing the dopaminergic inhibition of Aldo secretion at the adrenal level.

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