Sex difference in histamine metabolism in rats

1959 ◽  
Vol 197 (6) ◽  
pp. 1258-1260 ◽  
Author(s):  
K. S. Kim
Keyword(s):  
Sex Difference ◽  
Testosterone Propionate ◽  
Female Rats ◽  
Free Form ◽  
Total Output ◽  
Normal Female ◽  
Histamine Metabolism ◽  
Endogenous Histamine ◽  
Male And Female Rats ◽  
The Difference

The pattern of endogenous histamine excretion in the urine of male and female rats has been studied. The major sex difference is that females put out approximately 25 times more free histamine than males. This difference in free histamine output accounts for the difference in total output. Castration increased free histamine output in males, but ovariectomy or combined ovariectomy and hysterectomy have no effect on output in females. The castration effect appears in 2–5 weeks. One milligram of testosterone propionate when injected subcutaneously suppresses the output of free histamine in castrated rats, but not in normal female rats. There are also sex differences in the handling of exogenous histamine. Castrated and female rats excrete a larger proportion of exogenous histamine in the free form. This indicates that a difference in handling rather than in rate of production may account wholly or partly for the observed sex difference in endogenous histamine output.

Effect of the anterior pituitary gland and gonads on enzyme components of the hepatic microsomal cytochrome P-450 system of male and female rats

1983 ◽  
Vol 96 (2) ◽  
pp. 259-267 ◽  
Author(s):  
B. Gillham ◽  
J. S. M. Hutchinson ◽  
M. B. Thorn
Keyword(s):  
Sex Difference ◽  
Anterior Pituitary ◽  
Testosterone Propionate ◽  
Specific Activity ◽  
Female Rats ◽  
Intact Male ◽  
Adult Rats ◽  
Microsomal Cytochrome ◽  
Male And Female Rats ◽  
Cytochrome P 450

The concentration of cytochrome P-450 in microsomes prepared from the livers of mature female Wistar-derived rats was significantly lower than in mature males. This sex difference was abolished after hypophysectomy, when the concentration of the cytochrome in males and females was not significantly different from that in the intact male. A concentration of cytochrome P-450 characteristic of females was restored by two anterior pituitary transplants under the kidney capsule of hypophysectomized females; a partial 'feminization' occurred in similarly treated hypophysectomized males. A partial 'feminization' was also achieved by the administration of rat or sheep prolactin to hypophysectomized females. Unexpectedly, the administration of l-dihydroxyphenylalanine to normal females was without effect on cytochrome P-450, whereas in intact males 'feminization' resulted. Castration of adult rats resulted in the 'feminization' of cytochrome P-450, whereas ovariectomy was without effect. Administration of testosterone propionate for 10 days, either immediately after the operation or 14 weeks later to rats castrated when adult failed, however, to reverse the fall in cytochrome P-450. The establishment of a higher concentration of cytochrome P-450 in the liver of female rats could not be brought about by the administration of testosterone propionate, whether given as a single dose on the second day after birth or as a 10-day course of treatment after puberty or both. It is concluded that the sex difference in hepatic microsomal cytochrome P-450 is maintained by the release in the female of an anterior pituitary factor(s) that serves to depress its concentration. The factor(s) shows some of the characteristics of prolactin but the findings are not consistent with that hormone being responsible for all of the effects observed. The release of the factor(s) in the male may be inhibited by a compound of gonadal origin other than testosterone. A sex difference could not be 'imprinted' in the female by either neonatal and/or postpubertal testosterone treatment. The concentration of hepatic microsomal cytochrome b5 and the specific activity of NADPH-cytochrome c reductase were found not to be sex-dependent in the rats used. However, anterior pituitary factor(s) other than prolactin and growth hormone act to suppress partially the concentration of the former and to promote the specific activity of the latter in the endoplasmic reticulum of rat hepatocytes.

A SEX DIFFERENCE IN THE TEMPERATURE RESPONSE OF RATS TO EXERCISE

1965 ◽  
Vol 43 (3) ◽  
pp. 437-443 ◽  
Author(s):  
G. E. Thompson ◽  
J. A. F. Stevenson
Keyword(s):  
Sex Difference ◽  
Core Temperature ◽  
Temperature Response ◽  
Female Rats ◽  
Male And Female ◽  
Male And Female Rats ◽  
The Difference ◽  
Colonic Temperature ◽  
Response To Exercise ◽  
Skin Temperatures

The changes of colonic and tail skin temperatures were measured in male and female rats exercised on a motor-driven treadmill at a speed of 4.6 m/minute. The pattern of changes in these temperatures was the same in the two sexes except that the females tolerated a significantly higher colonic temperature than the males before beginning to vasodilate in the tail, and, perhaps as a result, the females regulated core temperature at a significantly higher level as exercise continued. Ovariectomy or prolonged (7–14 days) treatment with progesterone (12 mg/day) resulted in the temperature response to exercise of the female approaching that of the male, but not entirely eliminating the difference.

GONADOTROPHIN PATTERNS IN MALE AND FEMALE RATS:

1968 ◽  
Vol 58 (4) ◽  
pp. 600-612 ◽  
Author(s):  
Robert Boyd ◽  
Donald C. Johnson
Keyword(s):  
Ascorbic Acid ◽  
Testosterone Propionate ◽  
Female Rats ◽  
Female Rat ◽  
Feedback Effects ◽  
Male And Female ◽  
Prostate Weight ◽  
Male And Female Rats ◽  
Males And Females ◽  
Normal Males

ABSTRACT The effects of various doses of testosterone propionate (TP) upon the release of luteinizing hormone (LH or ICSH) from the hypophysis of a gonadectomized male or female rat were compared. Prostate weight in hypophysectomized male parabiotic partners was used to evaluate the quantity of circulating LH. Hypophyseal LH was measured by the ovarian ascorbic acid depletion method. Males castrated when 45 days old secreted significantly more LH and had three times the amount of pituitary LH as ovariectomized females. Administration of 25 μg TP daily reduced the amount of LH in the plasma, and increased the amount in the pituitary gland, in both sexes. Treatment with 50 μg caused a further reduction in plasma LH in males, but not in females, while pituitary levels in both were equal to that of their respective controls. LH fell to the same low level in partners of males or females receiving 100 μg TP. When gonadectomized at 39 days, males and females had the same amount of plasma LH, but males had more stored hormone. Pituitary levels were unchanged from controls following treatment with 12.5, 25 or 50 μg TP daily, but plasma values dropped an equal amount in both sexes with the latter two doses. Androgenized males or females, gonadectomized when 39 days old, were very sensitive to the effects of TP and plasma LH was significantly reduced with 12.5 μg daily. Pituitary LH in androgenized males was higher than that of normal males but was reduced to normal by small amounts of TP. The amount of stored LH in androgenized females was not different from that of normal females and it was unchanged by any dose of TP tested. Results are consistent with the conclusion that the male hypothalamic-hypophyseal axis is at least as sensitive as the female axis to the negative feedback effects of TP. Androgenization increases the sensitivity to TP in both males and females.

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.

INHIBITION OF SEXUAL DEVELOPMENT IN MALE AND FEMALE RATS TREATED WITH VARIOUS STEROIDS AT THE AGE OF FIVE DAYS

1965 ◽  
Vol 49 (2) ◽  
pp. 193-206 ◽  
Author(s):  
Fred A. Kind ◽  
A. Folch Pi ◽  
M. Maqueo ◽  
L. Herrera Lasso ◽  
A. Oriol ◽  
...  
Keyword(s):  
Sexual Development ◽  
Testosterone Propionate ◽  
Female Rats ◽  
Male And Female ◽  
Male And Female Rats

ABSTRACT The effect of various steroids injected into 5 day old male and female rats was evaluated at the age of 45 days. In the males the degree in which testes and accessory sex tissues were atrophied, and in the females the degree of inhibition of luteinization were the indices. Various synthetic oestrogens were potent inhibitors of sexual development in both sexes while androgens were less active. The activity of several oestrogens in this test does not correlate with oestrogenic potency as measured in the uterotrophic test. Testosterone propionate produced moderate atrophy of testes and accessory sex tissue but spermatogenesis was not impaired.

Sex Difference and Postnatal Change of Maternal Behavioral Patterns in Juvenile Male and Female Rats

2005 ◽  
Vol 22 (6) ◽  
pp. 695-699
Author(s):  
Satoshi Shima ◽  
Aya Urano ◽  
Lajos Korányi ◽  
Korehito Yamanouchi
Keyword(s):  
Sex Difference ◽  
Female Rats ◽  
Behavioral Patterns ◽  
Juvenile Male ◽  
Male And Female ◽  
Male And Female Rats ◽  
Postnatal Change

PREVENTION OF CENTRAL DEFEMINIZATION BUT NOT MASCULINIZATION IN MALE RATS BY INHIBITION NEONATALLY OF OESTROGEN BIOSYNTHESIS

1977 ◽  
Vol 74 (3) ◽  
pp. 375-382 ◽  
Author(s):  
J. T. M. VREEBURG ◽  
PAULA D. M. VAN DER VAART ◽  
P. VAN DER SCHOOT
Keyword(s):  
Sexual Function ◽  
Ovarian Function ◽  
Testosterone Propionate ◽  
Neonatal Period ◽  
Female Rats ◽  
Male Rats ◽  
Normal Male ◽  
Male And Female ◽  
Male And Female Rats ◽  
Copulatory Behaviour

SUMMARY An inhibitor of aromatization, androsta-1,4,6-triene-3,17-dione (ATD), was administered to newborn male and female rats and various parameters of gonadal and sexual function were examined in adulthood. Males injected with 1 mg ATD on the day of birth (day 1) and on days 3, 5, 10 and 15 postnatally, subsequently (day 55) showed normal male and female copulatory behaviour, but were not able to maintain cyclicity in ovarian transplants. When the ATD was administered by Silastic implants, however, cyclicity in ovarian transplants did occur. Neither form of treatment brought about significant changes in neonatal plasma or testicular testosterone concentrations. Female rats implanted on day 3 of life with Silastic capsules containing ATD and then given an injection of 0·25 mg testosterone propionate on day 5 subsequently showed normal ovarian function, whereas the controls receiving only testosterone propionate showed persistent vaginal cornification, anovulation and polyfollicular ovaries. The results support the view that the central conversion of testicular androgens to oestrogens during the neonatal period is necessary to abolish cyclic gonadotrophin release and to suppress female copulatory behaviour.

THE EFFECT OF HEPATECTOMY AND SEX HORMONES ON THE PSEUDOCHOLINESTERASE ACTIVITY IN LIVER AND SERUM OF THE RAT

1970 ◽  
Vol 65 (1) ◽  
pp. 184-192 ◽  
Author(s):  
R. S. Leeuwin ◽  
E. Th. Groenewoud
Keyword(s):  
Sex Hormones ◽  
Testosterone Propionate ◽  
Marked Decrease ◽  
Normal Values ◽  
Female Rats ◽  
Slow Increase ◽  
Male And Female Rats ◽  
Oestradiol Benzoate ◽  
Synthetic Capacity ◽  
Low Activity

ABSTRACT A study was made of the combined effects of hepatectomy, castration and treatment with sex hormones on the pseudocholinesterase activity in liver and serum of male and female rats. Hepatectomy in normal rats results in a sharp decline of the pseudocholinesterase activity, subsequently followed in females by a rapid increase to normal values and in males by a very slow increase. Hepatectomy in castrated rats also causes a marked decrease of the pseudocholinesterase activity, but the pseudocholinesterase activity remains at a relatively low level, in both castrated females and castrated males. Daily treatment of castrated-hepatectomized females with oestradiol-benzoate, either immediately or nine days after hepatectomy induces a gradual restoration of the enzyme activity to and above the normal castrate level. When castrated-hepatectomized males are treated daily with testosterone-propionate the extremely low activity may even be depressed further. These experiments once again stress the important role played by the liver and by sex hormones in the synthesis of the enzyme pseudocholinesterase. There was no evidence from our experiments that the steroid hormones affect the speed of regeneration of the liver as a whole. From this it must be decided that they only affect the restoration of the synthetic capacity for pseudocholinesterase. In all experiments the changes in liver pseudocholinesterase activity were reflected in the serum activity.

scholarly journals Stimulation of the corpora lutea of the rat by means of progesterone and testosterone

1937 ◽  
Vol 124 (836) ◽  
pp. 362-368 ◽  
Keyword(s):  
Guinea Pigs ◽  
Rhesus Monkeys ◽  
Testosterone Propionate ◽  
Female Rats ◽  
Corpora Lutea ◽  
Normal Female ◽  
Once Daily ◽  
Black And White ◽  
White Rats ◽  
Stimulation Of

The administration of progestin or progesterone inhibits oestrus in normal female experimental animals and leads to the cessation of follicular growth (Papanicolaou 1926, working on guinea-pigs; Gley 1928, on rats; Corner 1935, on monkeys). Active testicular extracts or testosterone have a similar effect (Ihrke and D’Amour 1931; Lendle 1931; and Robson 1936, working on rats; Zuckerman 1937, on rhesus monkeys). There is evidence that a phase of luteal activity occurs whenever the ripening of follicles is inhibited (see Evans 1928; Weichert 1930, amongst others), and it was therefore of interest to enquire whether or not luteinization of the ovaries is also an effect of the administration of progesterone and testosterone to normally cyclic female rats. Previous reports on this question are negative. Papanicolaou (1926) observed degenerative changes in the ovaries of guinea-pigs in which several successive oestrous cycles had been suppressed by means of progestin. Selye, Browne and Collip (1936) injected six rats with 4 mg. of progesterone for 12 days, and at the close of the experiment found that neither recent corpora lutea nor mature follicles were present in the ovaries. Albino and black and white rats were used. All injections were given once daily and subcutaneously. Oestrone was administered in aqueous solution, and both progesterone and testosterone propionate in oil. At the end of each experiment the uterus and one of the ovaries were fixed in Bouin’s fluid, and after sectioning, stained with haematoxylin and eosin, the ovary being sectioned serially. The second ovary of each animal was fixed in Flemming’s chrome-osmium fluid with acetic acid, and prepared to show osmicated fats according to the technique described by Deanesly (1930). In certain cases, noted below, the uterus was traumatized by the method of Shelesnyak (1933α) (a modification of that of Long and Evans), in order to produce deciduomata.

Sex Difference In Platelet Response To Aspirin Treatment

1981 ◽  
Author(s):  
N S Nicholson ◽  
S L Smith ◽  
R N Saunders
Keyword(s):  
Arachidonic Acid ◽  
Sex Difference ◽  
In Vitro Study ◽  
Female Rats ◽  
Platelet Response ◽  
Male And Female Rats ◽  
Males And Females ◽  
Spontaneous Aggregation

This study was done to determine if a sex difference in response to aspirin similar to that seen in the clinic could be demonstrated in an animal model with hyperactive platelets. The platelet hyperactivity which results in the spontaneous formation of platelet aggregates in retired breeder rats was reduced in both male and female rats by sulfinpyrazone, dipyridamole and indomethacin administered at 20 mg/kg. Aspirin blocked spontaneous aggregation in the male, but had no effect in the female even at doses of 100 mg/kg. Because aspirin is known to be an inhibitor of cyclooxygenase, the metabolism of arachidonic acid was studied in these rats. Arachidonic acid at 20 mg/kg was active in reducing spontaneous aggregation in the male, but had no effect in the female. However, in an in vitro study of the metabolism of arachidonic acid, no significant differences were seen between males and females in the conversion of arachidonic acid to PGF2α, PGE2, TXB2 or HHT. Aspirin was equally effective in both males and females in blocking the in vitro conversion of arachidonic acid via the cyclooxygenase pathway. The retired breeder rat provides a system for meaningful investigations toward understanding the human sex-related differences in platelet sensitivity with aspirin, although the mechanisms of the in vivo male/female platelet sensitivity have not been explained by in vitro studies thus far.

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