Sex difference in histamine metabolism in the rat

1961 ◽  
Vol 201 (2) ◽  
pp. 224-226 ◽  
Author(s):  
K. J. Netter ◽  
V. H. Cohn ◽  
P. A. Shore
Keyword(s):  
Sex Difference ◽  
Diamine Oxidase ◽  
Female Rats ◽  
Male Rats ◽  
Metabolizing Enzymes ◽  
Methyl Transferase ◽  
Endogenous Histamine ◽  
A Minor ◽  
Almost All

Female rats excrete much more free endogenous histamine than do males. The sex difference lies in histamine catabolism rather than biosynthesis, since females excrete, unchanged, a much higher percentage of injected histamine than do males. Investigation of the activity in vitro of the major histamine metabolizing enzymes, diamine oxidase (DAO) and imidazol-N-methyl transferase (IMT), showed no sex difference in distribution or activity, nor was there a sex difference in the activity of liver methionine-activating enzyme. Measurement of the biologic half-life of injected histamine revealed no sex difference in normal rats, in rats treated with the DAO inhibitor, aminoguanidine (AG), or in rats after nephrectomy, which removes almost all of IMT activity. A combination of AG and nephrectomy, however, resulted in a marked sex difference, which did not appear to be due to histamine conjugation or to liver drug-metabolizing enzymes. The findings suggest that male rats possess a minor histamine-metabolizing pathway which females lack.

Effects of in vivo gonadal hormone environment on in vitro hGRF-40-stimulated GH release

1985 ◽  
Vol 249 (3) ◽  
pp. E276-E280 ◽  
Author(s):  
W. S. Evans ◽  
R. J. Krieg ◽  
E. R. Limber ◽  
D. L. Kaiser ◽  
M. O. Thorner
Keyword(s):  
Female Rats ◽  
Male Rats ◽  
Gonadal Hormone ◽  
Base Line ◽  
Pituitary Cells ◽  
Intact Male ◽  
Castrate Male ◽  
Basal Release

The effects of gender and the gonadal hormone environment on basal and stimulated growth hormone (GH) release by dispersed and continuously perifused rat anterior pituitary cells were examined. Cells from intact male and diestrus day 2 female rats and from castrate male rats either untreated or treated with testosterone (T) or 17 beta-estradiol (E2) were used. Basal GH release (ng/min per 10(7) cells; mean +/- SE) by cells from diestrus day 2 female rats was less than by cells from castrate rats treated with T (4.3 +/- 0.6 vs. 11.4 +/- 2.7, respectively; P less than 0.025). No other differences in basal release were detected. Concentration-response relationships were documented between human GH-releasing factor 40 (hGRF-40; 0.03-100 nM given as 2.5-min pulses every 27.5 min) and GH release. Mean (+/- SE) overall GH release (ng/min per 10(7) cells) above base line was greater by cells from intact male rats (496 +/- 92) than by cells from castrate (203 +/- 37.3; P less than 0.0001), castrate and T-treated (348 +/- 52.8; P = 0.008), or castrate and E2-treated (58.1 +/- 6.8; P less than 0.001) male rats or by diestrus day 2 rats (68.6 +/- 9.5; P = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of Guanethidine and Related Compounds on Histamine Excretion

1972 ◽  
Vol 50 (6) ◽  
pp. 539-544 ◽  
Author(s):  
J. LeBlanc ◽  
J. Côté ◽  
F. Doré ◽  
S. Rousseau
Keyword(s):  
Peritoneal Fluid ◽  
Fold Increase ◽  
Female Rats ◽  
Male Rats ◽  
Daily Injection ◽  
Histamine Metabolism ◽  
Methyl Transferase ◽  
Single Intraperitoneal Injection ◽  
Urinary Histamine ◽  
Related Compounds

The basic nature of guanethidine and some of its effects suggested a possible action of this drug on histamine metabolism. A single intraperitoneal injection of guanethidine (10 mg/kg) in male rats was found to double the daily urinary excretion of free histamine; daily injection for three weeks caused a 10-fold increase. In male rats, guanethidine increased the number of mast cells in the peritoneal fluid and, in both peritoneal fluid and mesentery, caused a significant degranulation of these cells; this action was not observed in female rats. This finding may indicate that guanethidine blocks methylation of histamine by inhibiting imidazole methyl transferase since this enzyme is found in male but not in female rats. Bethanidine and reserpine had no effect on histamine excretion. Imidazole was found to be even more potent than guanethidine in causing an increase in urinary histamine. Guanethidine and imidazole neither potentiated nor mimicked the action of histamine on the isolated ileum.

Sex Differences in Cholinergic Analgesia I 

1999 ◽  
Vol 91 (5) ◽  
pp. 1447-1447 ◽  
Author(s):  
Astrid Chiari ◽  
Joseph R. Tobin ◽  
Hui-Lin Pan ◽  
David D. Hood ◽  
James C. Eisenach
Keyword(s):  
Sex Difference ◽  
Intrathecal Administration ◽  
Female Rats ◽  
Male Rats ◽  
Muscarinic Agonist ◽  
Noxious Heat ◽  
Male And Female Rats ◽  
Adrenergic Antagonist ◽  
Cholinergic Agents ◽  
Dose Dependent

Background Cholinergic agents produce analgesia after systemic and intrathecal administration. A retrospective review showed that intrathecal neostigmine was more potent in women than in men, suggesting a sex difference in this response. The purpose of this study was to determine whether such a sex difference exists in normal rats and to examine the pharmacologic mechanisms that underlie this difference. Methods Male and female rats with indwelling intrathecal catheters received injections of neostigmine, bethanechol (muscarinic agonist), or RJR-2403 (neuronal nicotinic agonist) alone or with atropine (muscarinic antagonist), mecamylamine (nicotinic antagonist), or phentolamine alpha-adrenergic antagonist) with antinociception determined to a noxious heat stimulus to the hind paw. Time versus subcutaneous paw temperature relationships were defined for males and females. Results Neostigmine produced dose-dependent antinociception with five times greater potency in female than in male rats. Neostigmine-induced antinociception was reversed in male rats by atropine and unaffected by mecamylamine, whereas it was partially reduced by each antagonist alone in females and completely reversed after injection of both. RJR-2403 was more potent in females than in males, whereas there was no sex difference to bethanechol. Phentolamine partially reversed antinociception from RJR-2403 in females. Paw temperature increased more rapidly in females than in males for the same lamp intensity. Conclusions These data demonstrate a large sex difference in antinociception to intrathecal neostigmine that is primarily the result of a nicotinic component in females. Phentolamine reversal suggests that part of this nicotinic component may rely on spinal norepinephrine release. A better understanding of this sex difference could lead to development of novel pain therapy for women.

FACTORS INFLUENCING THE EXCRETION OF A FAT-MOBILIZING SUBSTANCE IN THE URINE OF RATS

1966 ◽  
Vol 44 (1) ◽  
pp. 95-101 ◽  
Author(s):  
J. R. Beaton ◽  
A. J. Szlavko ◽  
J. A. F. Stevenson
Keyword(s):  
Body Weight ◽  
Sex Difference ◽  
Specific Activity ◽  
Young Male ◽  
Total Activity ◽  
Female Rats ◽  
Male Rats ◽  
Diabetic Rat ◽  
Adult Rats ◽  
Factors Influencing

The effect of various factors on excretion of a lipid-mobilizing activity in FMS IA (anorexigenic) and in FMS IB (fat-mobilizing) by the fasting rat has been investigated. During fasting, the greatest excretion of such activity in FMS IA and FMS IB occurred in the first 24 hours and diminished thereafter up to 72 hours; and the specific activity of FMS IB was greatest in the first 24 hours whereas that of FMS IA was constant throughout. The hypothalamicobese rat excretes FMS IA and FMS IB in greater than normal amounts. The alloxan-diabetic rat excretes less total activity of FMS IA and IB than do control animals. Young male rats excrete greater amounts of FMS IB, but not of FMS IA, than do adult rats, the greatest excretion per 100 g body weight being observed at approximately 37 days of age. At 27 days of age (prepuberty), male rats excreted a greater total activity of FMS IB but not of FMS IA than did female rats. At 90 days of age (post-puberty), there was no apparent sex difference in the amount of total activity of FMS IB excreted per rat, but when expressed per 100 g body weight, females excreted more FMS IB than did males.

IN VITRO STUDIES ON CARBOHYDRATE METABOLISM IN THE VITAMIN-B6-DEPRIVED RAT

1955 ◽  
Vol 33 (1) ◽  
pp. 562-567
Author(s):  
John R. Beaton
Keyword(s):  
Carbohydrate Metabolism ◽  
Vitamin B6 ◽  
Glucose Utilization ◽  
Female Rats ◽  
Male Rats ◽  
Vitamin B ◽  
Significant Difference ◽  
Aldolase Activity ◽  
Food Consumed

Following earlier studies on carbohydrate metabolism in the vitamin-B6-deprived rat, in vitro investigations have been carried out. In all cases, comparisons were made between tissues from vitamin-B6-deprived and pair-fed control animals so that differences in the amount of food consumed would not affect the interpretation of experimental results. No significant difference was found in glucose utilization by muscle nor in liver cytochrome oxidase activity. Liver aldolase activity was significantly decreased and the activity of plasma alkaline phosphatase was significantly increased in the vitamin-B6-deprived rats. In vitamin-B6-deprived female rats, but not male rats, liver catalase activity was significantly increased. These results are discussed in the light of earlier observations indicating disturbances in carbohydrate metabolism in the vitamin-B6-deprived rat.

STUDIES ON FACTORS INFLUENCING THE ACUTE TOXICITY OF MALATHION AND MALAOXON IN RATS

1967 ◽  
Vol 45 (4) ◽  
pp. 621-631 ◽  
Author(s):  
Jules Brodeur ◽  
K. P. DuBois
Keyword(s):  
Enzymatic Activity ◽  
Young Male ◽  
Female Rats ◽  
Male Rats ◽  
Age Difference ◽  
Adult Males ◽  
Organophosphate Insecticide ◽  
In Vitro Measurements ◽  
Immature Rats

A study was undertaken to investigate the mechanisms responsible for the higher susceptibility of immature rats to the organophosphate insecticide malathion. In vitro measurements of the activity of malathionase in the tissues of rats, at various time intervals after birth, indicated that the livers of immature rats detoxify the insecticide at a much slower rate than do the livers of adult animals. Evidence was obtained which showed that prolonged administration of testosterone causes a significant increase of the enzymatic activity in the livers of castrated young male rats and adult female rats. On the other hand, castration interferes with the maintenance of normal levels of malathionase in adult males and partially prevents the development of the activity in weanlings. Estradiol decreases the enzymatic activity in adult males. It appears, therefore, that the age difference in the susceptibility of rats to malathion might be due, to a large extent, to a slower rate of inactivation of the insecticide by the livers of immature animals. The results obtained also indicate that the sex hormones play an important role in the development and maintenance of normal levels of the enzyme system involved in the degradation of malathion in the livers of rats.

THE ROLE OF THE ADRENAL GLAND IN THE CONTROL OF AMINO ACID INCORPORATION INTO PROTEIN OF ISOLATED RAT LIVER MICROSOMES

1960 ◽  
Vol 21 (2) ◽  
pp. 177-189 ◽  
Author(s):  
A. KORNER
Keyword(s):  
Amino Acid ◽  
Rat Liver ◽  
Liver Microsomes ◽  
Female Rats ◽  
Male Rats ◽  
Rat Liver Microsomes ◽  
Hypophysectomized Rats ◽  
Normal Rat ◽  
Secondary Result

SUMMARY 1. Microsomes, isolated from rat liver a day after adrenalectomy, incorporate more radioactive amino acid into their protein in vitro than microsomes from normal rat liver. This enhanced rate of incorporation progressively declines with time after adrenalectomy until it reaches a plateau level which is below the normal rate of incorporation. 2. Following adrenalectomy microsomes isolated from liver of male rats show a greater rise in incorporating ability than those from liver of female rats, and maintain it longer. 3. Most of the increased incorporation observed in the in vitro system soon after adrenalectomy of the rat, and most of the decreased incorporation observed in rats adrenalectomized for some time, results from alterations in the microsomes which change their ability to incorporate activated amino acids into proteins. 4. Treatment of rats with cortisol acetate results in an increase in the ability of liver microsomes to incorporate amino acid into protein. This heightened incorporating ability is probably a secondary result of the breakdown of extrahepatic tissue protein which is stimulated by cortisol. 5. Somewhat similar responses to acute adrenalectomy and to treatment with cortisol were found in hypophysectomized rats. 6. The protein anabolic response of adrenalectomized rats to treatment with insulin, and of adrenalectomized-hypophysectomized rats to treatment with insulin or growth hormone, is greater than that shown by rats which possess adrenal glands.

Involvement of cGMP in LHRH-stimulated gonadotropin release.

1978 ◽  
Vol 235 (6) ◽  
pp. E586 ◽  
Author(s):  
Z Naor ◽  
C P Fawcett ◽  
S M McCann
Keyword(s):  
Mechanism Of Action ◽  
Female Rats ◽  
Male Rats ◽  
Camp Content ◽  
Luteinizing Hormone Releasing Hormone ◽  
Gonadotropin Release ◽  
Male And Female Rats ◽  
The Relationship ◽  
Stimulation Of

Anterior pituitary content of cyclic AMP (cAMP) and cyclic GMP (cGMP) has been measured during stimulation of gonadotropin release by luteinizing-hormone-releasing hormone (LHRH) in vitro to gain more information concerning the relationship between the mechanism of action of LHRH and cyclic nucleotides. During the increased gonadotropin release obtained by incubation by hemipituitaries with LHRH (0.25--25 X 10(-9) M) for 180 min, the glands taken from both male and female rats exhibited increased cGMP content, whereas cAMP content rose only in those taken from male rats. The increase in cGMP content was observed after only 2 min in the presence of LHRH (5 X 10(-9) M) and prior to augmented gonadotropin release. The increase in cAMP content in the male glands was detectable only after 60 min of incubation. These results suggest that cGMP might be involved in the mechanism of action of LHRH.

Vasopressin responses and receptors in the mesenteric vasculature of estrogen-treated rats

1986 ◽  
Vol 251 (5) ◽  
pp. H885-H889 ◽  
Author(s):  
J. St-Louis ◽  
A. Parent ◽  
R. Lariviere ◽  
E. L. Schiffrin
Keyword(s):  
Binding Sites ◽  
Pressor Response ◽  
Female Rats ◽  
Maximum Response ◽  
Male Rats ◽  
Ovariectomized Rats ◽  
Binding Characteristics ◽  
Vascular Bed ◽  
Mesenteric Vascular Bed

The effect of treatment with estrogens on the biological activity of arginine8 vasopressin (AVP) in the in vitro perfused mesenteric vascular bed and on the binding characteristics of [3H]AVP on membranes prepared from the same vascular bed was studied. Female rats treated with estradiol (400 micrograms/24 h sc), compared with ovariectomized rats, had an increase in the maximum response to AVP (from 128 +/- 3 to 153 +/- 3 mmHg) in the perfused preparation and an increase in the density of AVP binding sites (from 402 to 732 fmol/mg protein) in the membrane preparation. In male rats, the injection of estradiol increased the maximum response to AVP (from 109 +/- 4 to 137 +/- 3 mmHg) and the density of AVP binding sites (from 289 to 519 fmol/mg protein). The effective concentration producing 50% of maximum response of AVP in the perfused preparation was higher in male than in female rats, while the Kd in the binding experiments was similar in the four experimental groups. Our results show that estrogens upregulate the number of AVP binding sites, leading to an increase in the pressor response to AVP in the rat mesenteric vascular bed.

Role of estrogens and age in flow-mediated outward remodeling of rat mesenteric resistance arteries

2014 ◽  
Vol 307 (4) ◽  
pp. H504-H514 ◽  
Author(s):  
K. Tarhouni ◽  
M. L. Freidja ◽  
A. L. Guihot ◽  
E. Vessieres ◽  
L. Grimaud ◽  
...  
Keyword(s):  
Blood Flow ◽  
Female Rats ◽  
Male Rats ◽  
Resistance Arteries ◽  
Cross Sectional ◽  
Male And Female ◽  
Male And Female Rats ◽  
Arterial Contractility

In resistance arteries, a chronic increase in blood flow induces hypertrophic outward remodeling. This flow-mediated remodeling (FMR) is absent in male rats aged 10 mo and more. As FMR depends on estrogens in 3-mo-old female rats, we hypothesized that it might be preserved in 12-mo-old female rats. Blood flow was increased in vivo in mesenteric resistance arteries after ligation of the side arteries in 3- and 12-mo-old male and female rats. After 2 wk, high-flow (HF) and normal-flow (NF) arteries were isolated for in vitro analysis. Arterial diameter and cross-sectional area increased in HF arteries compared with NF arteries in 3-mo-old male and female rats. In 12-mo-old rats, diameter increased only in female rats. Endothelial nitric oxide synthase expression and endothelium-mediated relaxation were higher in HF arteries than in NF arteries in all groups. ERK1/2 phosphorylation, NADPH oxidase subunit expression levels, and arterial contractility to KCl and to phenylephrine were greater in HF vessels than in NF vessels in 12-mo-old male rats only. Ovariectomy in 12-mo-old female rats induced a similar pattern with an increased contractility without diameter increase in HF arteries. Treatment of 12-mo-old male rats and ovariectomized female rats with hydralazine, the antioxidant tempol, or the angiotensin II type 1 receptor blocker candesartan restored HF remodeling and normalized arterial contractility in HF vessels. Thus, we found that FMR of resistance arteries remains efficient in 12-mo-old female rats compared with age-matched male rats. A balance between estrogens and vascular contractility might preserve FMR in mature female rats.

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