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.

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

COMPARATIVE ICSH-ESTIMATIONS IN THE SERUM OF GONADECTOMIZED MALE AND FEMALE RATS WITH A TRANSPLANTED OVARY

1965 ◽  
Vol 49 (2) ◽  
pp. 239-247 ◽  
Author(s):  
T. Swelheim
Keyword(s):  
Female Rats ◽  
Ventral Prostate ◽  
High Dose ◽  
Corpora Lutea ◽  
Male And Female ◽  
Single High Dose ◽  
Base Level ◽  
Male And Female Rats ◽  
The Difference ◽  
The Right

ABSTRACT In adult female rats an ICSH-peak in the serum was found in the afternoon of pro-oestrus (preliminary experiments). ICSH was determined by the ventral prostate assay. Comparative ICSH-determinations were carried out in the serum of adult gonadectomized male and female rats with an ovarian transplant. Gonadectomy and transplantation of an ovary into the right hind-leg had been carried out two months previously. Irrespective as to whether there were corpora lutea in the transplants of castrated males, the ICSH-level in the serum of the males did not differ from the base level in the serum of the females. The ICSH-peak in the serum of the females (afternoon of pro-oestrus) exceeded this level. The relation between the ICSH-peak in the serum and ovulation was demonstrated by the fact that there was no ICSH-peak on the day of prooestrus in spayed females with an ovarian transplant, which in previous cycles had passed through a two days' oestrus. It is suggested that the difference in behaviour between ovarian transplants in spayed females and castrated males might be an expression of the same sex difference as that which appears in response to a single high dose of oestrogen.

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.

Change from beta- to alpha-adrenergic glycogenolysis induced by corticosteroids in female rat liver

1997 ◽  
Vol 273 (1) ◽  
pp. R153-R160
Author(s):  
M. Moriyama ◽  
Y. Nakanishi ◽  
S. Tsuyama ◽  
Y. Kannan ◽  
M. Ohta ◽  
...  
Keyword(s):  
Glucose Production ◽  
Plasma Corticosterone ◽  
Mature Female ◽  
Female Rats ◽  
Male Rats ◽  
Female Rat ◽  
Circadian Variations ◽  
Male And Female ◽  
Male And Female Rats ◽  
The Difference

The conversion of beta- to alpha-adrenergic glycogenolysis by corticosteroids was studied in perfused livers of mature female rats. Isoproterenol stimulated glucose production more effectively in female rats than in male rats, but the difference in its stimulatory effect disappeared in adrenalectomized (ADX) rats, whereas it remained in adrenodemedulated rats. When ADX female rats were treated with dexamethasone sulfate, alpha-responses increased and beta-responses decreased, depending on the concentration of dexamethasone sulfate. The treatment of female rats with 1.5 mg/kg dexamethasone sulfate changed the levels of the alpha- and beta-responses to those observed in male rats, and the changes were associated with changes in the number of receptors. Although periodicity of changes in plasma corticosterone levels was observed in both male and female rats, the extent of circadian variations was significantly lower in female rats during the estrous cycle than in male rats. The variations in plasma corticosterone levels and in both alpha- and beta-responses after ovariectomy approached those in male rats. The results suggest that the level of plasma corticosterone might play an important role in the regulation of the relative levels of alpha- and beta-adrenergic responses in female rats.

scholarly journals Sex difference in resting pituitary-adrenal function in the rat

1963 ◽  
Vol 205 (5) ◽  
pp. 807-815 ◽  
Author(s):  
V. Critchlow ◽  
R. A. Liebelt ◽  
M. Bar-Sela ◽  
W. Mountcastle ◽  
H. S. Lipscomb
Keyword(s):  
Sex Difference ◽  
Ovarian Function ◽  
Adrenal Function ◽  
Neural Mechanisms ◽  
Female Rats ◽  
Male And Female ◽  
Male And Female Rats ◽  
Environmental Lighting ◽  
Lighting Regimen

Resting levels of plasma and adrenal corticosteroids, pituitary content of adrenocorticotropin, and circulating leukocytes were determined at intervals during controlled 24-hr light-dark cycles in intact, castrated, sham-castrated adult and prepubertal male and female rats. To study the influence of environmental lighting rhythms, corticosteroid levels were similarly followed in intact and blinded male and female rats and in ovariectomized females following a 9-hr shift in lighting regimen. All groups of animals showed evidence of cyclic pituitary-adrenal function, but the presence of mature ovaries was associated with marked facilitation of the diurnal excursions in corticosteroid levels. Furthermore, the results indicated that the mechanisms responsible for pituitary-adrenal rhythmicity are influenced by cyclic ovarian function, are sensitive to pentobarbital, and are synchronized by environmental lighting rhythms perceived through the eyes. Several of the features of pituitary-adrenal function under resting conditions resemble those associated with cyclic release of gonadotropin leading to ovulation. Similar or overlapping neural mechanisms may be responsible for these endocrine rhythms.

Sex difference in growth hormone feedback in the rat

1990 ◽  
Vol 126 (1) ◽  
pp. 27-35 ◽  
Author(s):  
L. M. S. Carlsson ◽  
R. G. Clark ◽  
I. C. A. F. Robinson
Keyword(s):  
Growth Hormone ◽  
Sex Difference ◽  
Female Rats ◽  
Male Rats ◽  
Constant Infusion ◽  
Physiological Control ◽  
Sampling System ◽  
Male And Female ◽  
Gh Secretion ◽  
Male And Female Rats

ABSTRACT Growth hormone inhibits its own secretion in animals and man but the mechanism for this inhibition is unclear: both stimulation of somatostatin release and inhibition of GH-releasing factor (GRF) release have been implicated. We have now studied the GRF responsiveness of conscious male and female rats under conditions of GH feedback induced by constant infusion of exogenous human GH (hGH). Intravenous infusions of hGH (60 μg/h) were maintained for 3 to 6 h whilst serial injections of GRF(1–29)NH2 (0·2–1 μg) were given at 45-min intervals. The GH responses were studied by assaying blood samples withdrawn at frequent intervals using an automatic blood sampling system. We have confirmed that male and female rats differ in their ability to respond to a series of GRF injections; female rats produced consistent GH responses for up to 13 consecutive GRF injections, whereas male rats showed a 3-hourly pattern of intermittent responsiveness. In female rats, multiple injections of GRF continued to elicit uniform GH responses during hGH infusions, whereas hGH infusions in male rats disturbed their intermittent pattern of responsiveness to GRF, and their regular 3-hourly cycle of refractoriness was prolonged. We suggest that this sex difference in GH feedback may be due to GH altering the pattern of endogenous somatostatin release differentially in male and female rats. Such a mechanism of GH autofeedback could be involved in the physiological control of the sexually differentiated pattern of GH secretion in the rat. Journal of Endocrinology (1990) 126, 27–35

PUBERTAL MANIFESTATION OF SEX DIFFERENCE IN CIRCADIAN RHYTHM OF CORTICOTROPHIN-RELEASING ACTIVITY IN THE RAT HYPOTHALAMUS

1977 ◽  
Vol 86 (2) ◽  
pp. 225-234 ◽  
Author(s):  
Sato Honma ◽  
Tsutomu Hiroshige
Keyword(s):  
Circadian Rhythm ◽  
Sex Difference ◽  
Developmental Change ◽  
Marked Change ◽  
Female Rats ◽  
Male Rats ◽  
Ovarian Activity ◽  
Essential Difference ◽  
Male And Female ◽  
Male And Female Rats

ABSTRACT Post-natal development of the circadian rhythm of hypothalamic content of corticotrophin-releasing factor (CRF) was examined in male and female rats, separately. CRF activity was estimated by the intrapituitary injection technique. The circadian rhythm of the CRF content observed at the third week was without any noticeable sex difference: both male and female rats began their circadian rhythm with higher values in the afternoon than in the morning. Male rats maintained this pattern up to maturity. In contrast, female rats showed a marked change at ages of fifth to sixth week: the CRF rhythm in female rats changed to a female pattern, with higher values in the morning than in the afternoon. During this period, the vaginal opening occurred concurrently with a marked afternoon rise in the plasma corticosterone, characteristic of mature female rats. On the other hand, no essential difference could be observed between male and female rats in the developmental change in the circadian rhythm of locomotor activity. These results indicate that a sex difference in the CRF rhythm is not essentially related to the process of sex differentiation in the central nervous system, but is rather related to changes in ovarian activity following the onset of puberty.

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