Effects of Muscular Work on Cortisol and Corticosterone Content in the Blood and Adrenals of Guinea Pigs

Abstract

The cortisol and corticosterone content was determined fluorometrically in the blood and in the adrenals of guinea pigs. After three 5-minute\x=req-\ swimming sets the corticoid content increased in the adrenals, but remained unchanged in the blood. After 5-minute-swimming sets repeated until exhaustion, the adrenal corticoid content did not differ from the level of the control group. The blood cortisol content, however, fell significantly. The blood corticosterone content did not change. If before the swimming sets 4 IU of corticotrophin were administered, the cortisol content both in the adrenals and blood at the point of exhaustion was somewhat higher than in the control group. The decrease in blood corticoid concentration during long-lasting muscular work is due to insufficient stimulation of the adrenocortical activity. It has been suggested that the inhibition of the stimulation of the adrenocortical activity is one manifestation of a general defence reaction, against the fatal depletion of the resources of the organism.Determinations of the adrenocortical hormones and their metabolites in urine and blood during muscular exercise have not given constant results. Usually, during long-lasting exercise, a decrease in the excretion (Rivoire et al. 1953;Thorn et al. 1953;Bugard et al. 1961) and in the blood concentration of the corticoids (Stachelin et al. 1955;Cornil et al. 1965) is observed and this is considered to be connected with fatigue. The decreased excretion and corticoids concentration in the plasma is preceded by a period of augmented excretion

Influence of prolonged continuous exercise on hormone responses to subsequent exercise in humans

“…These ®ndings were later con®rmed in other human studies involving prolonged exercise (an initial increase in blood corticosteroid concentration was followed by decreases; Staehelin et al 1955;Viru et al 1973). Animal experiments also demonstrated similar ®ndings; that is, blood concentrations of glucocorticoids increased after short-term and decreased after prolonged exercise lasting several hours (KoÄ rge et al 1974;Viru and A È kke 1969). Interestingly, an administration of corticotropin (ATCH) eliminated the decrease in the activity of the adrenocortical system during the exercise (Viru and A È kke 1969).…”

“…Animal experiments also demonstrated similar ®ndings; that is, blood concentrations of glucocorticoids increased after short-term and decreased after prolonged exercise lasting several hours (KoÄ rge et al 1974;Viru and A È kke 1969). Interestingly, an administration of corticotropin (ATCH) eliminated the decrease in the activity of the adrenocortical system during the exercise (Viru and A È kke 1969). Thus, the reason for the subnormal activity of the adrenocortical system did not appear to be exhaustion of the adrenocortical cells (Viru and A È kke 1969).…”

“…Interestingly, an administration of corticotropin (ATCH) eliminated the decrease in the activity of the adrenocortical system during the exercise (Viru and A È kke 1969). Thus, the reason for the subnormal activity of the adrenocortical system did not appear to be exhaustion of the adrenocortical cells (Viru and A È kke 1969). These above ®ndings were dismissed as primarily aberrations of the less speci®c methods for hormone analysis employed at the time of the studies (i.e.…”

“…These above ®ndings were dismissed as primarily aberrations of the less speci®c methods for hormone analysis employed at the time of the studies (i.e. colorometric and¯uoro-metric assays, KoÄ rge et al 1974;Staehelin et al 1955;Viru and A È kke 1969;Viru et al 1973), especially after the advent of the highly speci®c and precise immunoassay methods.…”

The effects of psychosomatic stress at the end of pregnancy on maternal and fetal plasma cortisol levels and liver glycogen in guinea-pigs

“…In this strain, prepartum labor lasts at least 2 dayt (Dalle, unpublished observations), and it is possible that adrenaline would no longer be secreted, as in the case of recurring and iterative stress (Mikulaj et al, 1974 ;Kvetnansky et al, 1977 ;Burchfield, 1979). The decrease in the intensity of adrenal response to stress at this stage of pregnancy seems logical ; in fact, the efficiency of adrenal response to stress has often been demonstrated to be inversely related to the intensity of the stimulation before stress, as shown in guinea-pig by Viru and Akke (1969).…”