Studies on Plasma Corticosteroids in the Rhesus Monkey (Macaca Mulatta)

Abstract

The physiological regulation of the plasma corticosteroid concentration, measured by competitive protein-binding, was studied in female rhesus monkeys (M. mulatta) sedated with phencyclidine hydrochloride. Morning basal levels of plasma corticosteroids were found to be in the range 8\ m=. \ 0\ p=n-\ 25\ m=. \ 2 \g=m\g/100ml, which is lower than that previously reported in this species. A circadian rhythm in plasma cortisol concentration was demonstrated. Prolonged sedation with phencyclidine was associated with a gradual increase in the plasma cortisol concentration. Synthetic \ g=a\ 1\ p=n-\ 24 adrenocorticotrophic hormone given intravenously caused a rapid rise in plasma cortisol, the minimum effective dose was between 1 and 10 ng/kg body weight and the response was maximal after 1000 ng/kg. The administration of lysinevasopressin and the induction of hypoglycaemia by insulin were both followed by an increase in the plasma corticosteroid concentration. Metyrapone caused a decline in plasma 11-hydroxycorticosteroids and a concomitant increase in total corticosteroids measured by competitive protein-binding. It is concluded that the hypothalamic-pituitary-adrenal system in the rhesus monkey functions in a manner which is qualitatively and quantitatively similar to that of man.

Self-administration of fentanyl, cocaine and ketamine: effects on the pituitary?adrenal axis in rhesus monkeys

“…present study). In the study by Setchell et al (1975), a fall in cortisol was measured in all subjects during the first 60 min after phencyclidine injection, which is consistent with the findings of the present study. It is only after a more prolonged period of anesthetization (and additional dosing with phencyclidine) that the cortisol levels began to increase.…”

“…As with fentanyl, the low basal levels of ACTH and cortisol prior to the session may have precluded the measurement of further decreases as intake increased. There are some data in rhesus monkeys (Setchell et al 1975;Elvidge et al 1976) and humans (Adams et al 1992) with which to compare our findings. In these studies, the HPA axis effects of large doses of ketamine or phencyclidine, sufficient to produce anesthetization, were reported.…”

“…NMDA antagonists such as AP5 and MK-801 block the stimulatory effect of NMDA on ACTH in rats (Farah et al 1991;Jezova et al 1991). However, anesthetizing doses of the NMDA antagonists PCP or ketamine produced increases in ACTH and cortisol when administered to rhesus monkeys (Setchell et al 1975;Elvidge et al 1976) or humans (Adams et al 1992). It is possible that the paradoxical effect of NMDA antagonists on HPA axis function in primates may be based on the magnitude of the dose and the duration of its administration.…”

Extremely High Levels of Corticosteroids and Low Levels of Corticosteroid Binding Macromolecule in Plasma of Marmoset Monkeys

“…These samples were used for determining the resting level of plasma corticosteroids. After the blood collection was completed, 50 tig of synthetic /J1-24 ACTH (Cortrosyn®), supraphysiological dose (Setchell et al 1975), was administered intramuscularly to the Japanese monkeys, and 10 fig to the tamarins. One or two hours after ACTH administration, blood was collected and plasma corticosteroid levels were determined.…”

Novel Application of Nonhuman Primate Tethering System for Evaluation of Acute Phase SIVmac251 Infection in Rhesus Macaques (Macaca mulatta)

“…Studies of the stress induced in NHPs during chair restraint have shown increased cardiovascular activity (19), increases in cortisol levels (13), and changes in digestion (50). Likewise, sedation of the animals for sampling also increases cortisol levels (57), profoundly affects the urinary system (15), increases prolactin levels (52), and causes a decrease in daily food intake up to 4 d after sedation (58). Comparisons of restraint and sedation techniques showed no differences in the cortisol levels across techniques (11).…”