PITUITARY–ADRENAL FUNCTION IN THYROPARATHYROIDECTOMIZED MALE AND FEMALE RATS

1976 ◽  
Vol 71 (1) ◽  
pp. 47-50 ◽  
Author(s):  
J. D. DUNN ◽  
M. E. HESS
Keyword(s):  
Stress Response ◽  
Peak Plasma ◽  
Plasma Corticosterone ◽  
Adrenal Function ◽  
Female Rats ◽  
Adrenocortical Function ◽  
Dark Phase ◽  
Intact Control ◽  
Male And Female ◽  
Male And Female Rats

SUMMARY The influence of thyroid hormones on pituitary–adrenal function was assessed by studying several aspects of adrenocortical function approximately 30 days after thyroparathyroidectomy (TPTx). Both male and female rats showed evidence of rhythmic adrenocortical activity; peak plasma corticosterone levels occurred just before the dark phase of the lighting schedule. Only the amplitude of the rhythm appeared altered by TPTx. Peak plasma corticosterone levels in TPTx male and female animals were less (P < 0·05) than corresponding levels in intact control rats. Both sexes showed significant responses to stress, but the morning stress response in TPTx females was less (P < 0·01) than the stress response in intact controls. Concomitant with the reduced stress response, the adrenocortical response to exogenous ACTH was reduced in TPTx female rats.

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.

scholarly journals Brief anesthesia by isoflurane alters plasma corticosterone levels distinctly in male and female rats: Implications for tissue collection methods

2016 ◽  
Vol 305 ◽  
pp. 122-125 ◽  
Author(s):  
Mandakh Bekhbat ◽  
Liana Merrill ◽  
Sean D. Kelly ◽  
Vanessa K. Lee ◽  
Gretchen N. Neigh
Keyword(s):  
Plasma Corticosterone ◽  
Female Rats ◽  
Male And Female ◽  
Male And Female Rats ◽  
Collection Methods

scholarly journals Adolescence and the ontogeny of the hormonal stress response in male and female rats and mice

2016 ◽  
Vol 70 ◽  
pp. 206-216 ◽  
Author(s):  
Russell D. Romeo ◽  
Ravenna Patel ◽  
Laurie Pham ◽  
Veronica M. So
Keyword(s):  
Stress Response ◽  
Female Rats ◽  
Male And Female ◽  
Male And Female Rats ◽  
Rats And Mice

CYCLICAL CHANGES IN CONCENTRATIONS OF α-MELANOTROPHIN IN THE PLASMA OF MALE AND FEMALE RATS

1979 ◽  
Vol 82 (3) ◽  
pp. 361-366 ◽  
Author(s):  
J. F. WILSON ◽  
MERRILL A. MORGAN
Keyword(s):  
Time Series ◽  
Time Series Analysis ◽  
Diurnal Rhythm ◽  
Dark Period ◽  
Light Period ◽  
Female Rats ◽  
Male Rats ◽  
Dark Phase ◽  
Male And Female ◽  
Male And Female Rats

Radioimmunoassay measurements of α-melanotrophin in plasma have identified a diurnal rhythm in male rats. Animals maintained on a 12 h light: 12 h darkness photoperiod had raised levels of plasma α-melanotrophin during the dark phase. Time-series analysis gave a fitted mean level of α-melanotrophin of 52·4 pmol/l, an amplitude of 12·1 pmol/l and peak levels 2·2 h before dawn. Measurements throughout the oestrous cycle in female rats showed that similar variations between the dark and light phases occurred on the 2 days of dioestrus. The raised levels during the dark period were, however, absent on the nights of pro-oestrus and oestrus. During this pro-oestrous/oestrous period, plasma α-melanotrophin levels were below average but higher than the normal minimum levels found during the light period.

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.

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