Seasonal changes in plasma and adrenal concentrations of cortisol, corticosterone, aldosterone, and electrolytes in the adult male sand rat (Psammomys obesus)

Amirat, Zaïna; Khammar, Farida; Brudieux, R

doi:10.1016/0016-6480(80)90093-3

Cited by 31 publications

(23 citation statements)

References 10 publications

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“…Hormones were separated by paper chromatography (Bush B5 solvent system, no. 2 Whatman paper), as previously described (Amirat et al, 1980). Next, hormones were measured by radioimmunoassay (RIA) using specific antibodies raised in rabbit, kindly provided by Prof. Claustrat (Lyon, France) and by Prof. Oliver (Marseille, France).…”

Section: Cortisol Assaymentioning

confidence: 99%

“…Marple et al, 1972), its activity may be a good index of the intensity of adaptive adjustments. Indeed, we previously described large seasonal changes in HPA axis activity in a wild desert species, the sand rat (Amirat et al, 1980). In order to evaluate the intensity of adaptation processes in the Bedouin buck exposed to extreme environmental conditions around the year in the Sahara desert, we investigated the seasonal changes in circadian plasma cortisol concentrations, rectal temperature, BW and in the reactivity of the adrenal cortex to exogenous ACTH.…”

Section: Introductionmentioning

confidence: 99%

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Seasonal effects on plasma cortisol concentrations in the Bedouin buck: circadian studies and response to ACTH

Chergui¹,

Mormède²,

Foury³

et al. 2017

Animal

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Our work aims at the exploration of cortisol secretion in the Bedouin goat, native to the Algerian Sahara desert, to understand the mechanisms of adaptation to extreme hot climates. In the present study, diurnal and seasonal variations of cortisol concentrations were measured in basal conditions, as well as the response to ACTH stimulation tests across seasons in bucks. The plasma concentrations of cortisol showed no diurnal cycle but a large variation across seasons. The highest levels occurred in summer and winter when the environmental conditions are at their extreme levels. The rectal temperature showed nychthemeral and seasonal variations, and BW was also different across seasons with highest values in summer and lowest in winter. The results obtained after administration of two doses (2 or 10 μg/kg BW) of synthetic ACTH to three different age groups (kids, adults and elderly animals) showed a strong increase in plasma cortisol concentrations under all conditions with maximum levels achieved between 15 and 120 min. The analysis of the area under the cortisol curve showed no significant difference between the responses to the two doses of ACTH and between age groups, but showed seasonal variations with the lowest response in autumn than in other seasons. We conclude that season significantly affects secretion of cortisol in both basal state and under ACTH stimulation. However, the variation of adrenal reactivity to ACTH is not sufficient to explain seasonal differences, and in particular the summer peak in basal circulating cortisol concentrations. Further research should focus on the respective contribution of environmental factors (such as day length, temperature, humidity) and the mechanisms involved in cortisol regulation.

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Section: Cortisol Assaymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Seasonal effects on plasma cortisol concentrations in the Bedouin buck: circadian studies and response to ACTH

Chergui¹,

Mormède²,

Foury³

et al. 2017

Animal

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“…2 paper), by a radioimmunoassay method for aldosterone using the antialdosterone dihcmisuccinate -BSA antiserum, kindly sup plied by the NIADDK (Bethesda, Md., USA) and by a competitive protein binding radioassay for corticosterone, using a 0.2% diluted adrenalcctomized female rat plasma. Details and validity of these methods have been described elsewhere [19].…”

Section: Hormone Assaysmentioning

confidence: 99%

Age-Related Change in Plasma Aldosterone Response to Exogenous Angiotensin II in the Rat

Rakotondrazafy¹,

Brudieux²

1993

Horm Res

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Age-related changes in aldosterone response of the adrenal cortex to exogenous angiotensin II were studied in old compared to adult Long-Evans female rats. All animals were pretreated with dexamethasone and captopril and anesthetized with pentobarbital. Continous infusion of angiotensin II (20 and 300 ng/min per 100 g body weight) for 20 and 30 min markedly enhanced the plasma concentration of aldosterone; however, the plasma aldosterone incremental response was significantly lower (-66.8% after the highest dose of angiotensin II) in old than in adult rats. These results, the first in the rat, suggest that the previously reported diminished aldosterone secretion is, at least in part, due to an impaired aldosterone biosynthesis capacity of the adrenal glomerular cells in response to angiotensin II.

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“…The plasma levels of glucocorticoids in P. obesus vary during the annual cycle, they decrease in summer [36] when b-endorphin expression appears. Since the classic glucocorticoid receptor was expressed in rat Leydig cells [37] and spermatocytes I at zygotene and early pachytene stages [38] it may be also involved in this inhibitory action in P. obesus.…”

Section: Discussionmentioning

confidence: 99%

17β-estradiol effect on testicular β-endorphin expression in Psammomys obesus

Madani¹,

Moudilou²,

Exbrayat³

et al. 2015

Folia Histochem Cytobiol.

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Introduction. Testicular function in the sand rodent Psammomys obesus is subjected to seasonal alternations with a trigger of spermatogenesis in winter and a total quiescence which extends from late spring to summer. The aim of this study was to investigate the distribution of b-endorphin in the testis at the period of winter sexual activity and at its summer regression, and assess the effect of 17b-estradiol treatment on testicular morphology and b-endorphin expression. Material and methods. The adult males were grouped into 4 groups (rest group, sexually active group, rest treated with 17b-estradiol group and controls at sexual rest injected with olive oil, n = 5 in each group). Using anti-serum against b-endorphin, we studied its testicular expression by Western blot and cellular location by immunohistochemical (IHC) method, respectively. Results. We detected by Western blot a peptide of 3.5 kDa molecular weight corresponding to b-endorphin only in sexually resting and control males. The 17b-estradiol treatment induced a clear reduction in the b-endorphin band expression compared with the latter. These results were confirmed by the IHC analysis since b-endorphin was only observed in the testis at sexual rest and in controls, in majority of seminiferous tubules at the level of germ cells. The intensity of IHC labeling was significantly different between spermatogonia and spermatocytes I or round spermatids which revealed the strongest labeling. The intense immunoreactivity was also located in Leydig cells and highly significantly varied compared to the germ cells. The 17b-estradiol treatment decreased significantly the b-endorphin signal in germ cells but not in Leydig cells. Conclusion. The 17b-estradiol treatment induces a repressive effect on seasonal testicular endorphinergic system in P. obesus and this action targets exclusively the germ cells.

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Seasonal changes in plasma and adrenal concentrations of cortisol, corticosterone, aldosterone, and electrolytes in the adult male sand rat (Psammomys obesus)

Cited by 31 publications

References 10 publications

Seasonal effects on plasma cortisol concentrations in the Bedouin buck: circadian studies and response to ACTH

Seasonal effects on plasma cortisol concentrations in the Bedouin buck: circadian studies and response to ACTH

Age-Related Change in Plasma Aldosterone Response to Exogenous Angiotensin II in the Rat

17β-estradiol effect on testicular β-endorphin expression in Psammomys obesus

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