CIRCADIAN RHYTHMS OF PLASMA CORTICOSTERONE BINDING ACTIVITY IN THE RAT AND THE MOUSE

1979 ◽  
Vol 91 (1) ◽  
pp. 150-157 ◽  
Author(s):  
John E. Ottenweller ◽  
Albert H. Meier ◽  
Albert C. Russo ◽  
Marie E. Frenzke
Keyword(s):  
Locomotor Activity ◽  
Circadian Rhythms ◽  
Protein Binding ◽  
Peak Level ◽  
Plasma Corticosterone ◽  
Binding Activity ◽  
Plasma Samples ◽  
Late Afternoon ◽  
Competitive Protein Binding ◽  
Rats And Mice

ABSTRACT Corticosterone binding activity (CBA) and corticosteroids were measured by competitive protein binding techniques in plasma samples drawn from rats and mice at different times of day. Circadian rhythms of plasma CBA were found in both rats (onset of 14-h daily photoperiod: 0600) and mice (onset of 14-h daily photoperiod: 0700). The plasma CBA rhythm was bimodal in rats with peaks at 1000 and 1800 and unimodal in mice with peak level from 0100 to 0500. Circadian rhythms of plasma corticosteroid concentration with peaks during the late afternoon were confirmed in both rats and mice. The plasma CBA rhythms appear to be related to the circadian rhythms of both locomotor activity and plasma corticosteroid concentration.

Internal synchronization among several circadian rhythms in rats under constant light

1978 ◽  
Vol 235 (5) ◽  
pp. R243-R249 ◽  
Author(s):  
K. I. Honma ◽  
T. Hiroshige
Keyword(s):  
Locomotor Activity ◽  
Body Temperature ◽  
Circadian Rhythms ◽  
Continuous Light ◽  
Biological Rhythms ◽  
Plasma Corticosterone ◽  
Dark Cycle ◽  
Internal Oscillator ◽  
Free Running ◽  
Phase Angles

Three biological rhythms (locomotor activity, body temperature, and plasma corticosterone) were measured simultaneously in individual rats under light-dark cycles and continuous light. Spontaneous locomotor activity was recorded on an Animex and body temperature was telemetrically monitored throughout the experiments. Blood samples were obtained serially at 2-h intervals on the experimental days. Phase angles of these rhythms were calculated by a least-squares spectrum analysis. Under light-dark cycles, the acrophases of locomotor activity, body temperature, and plasma corticosterone were found at 0029, 0106, and 1940 h, respectively. When rats were exposed to 200 lx continuous light, locomotor activity and body temperature showed free-running rhythms with a period of 25.2 h on the average. Plasma corticosterone levels determined at 12 days after exposure to continuous light exhibited a circadian rhythm with the acrophase shifted to 0720. The acrophases of locomotor activity and body temperature, determined simultaneously on the same day, were found to be located at 1303 and 1358 h, respectively. Phase-angle differences among the three rhythms on the 12th day of continuous light were essentially the same with those under the light-dark cycle. These results suggest that circadian rhythms of locomotor activity, body temperature, and plasma corticosterone are most probably coupled to a common internal oscillator in the rat.

scholarly journals Selected Factors that Affect the Measurement of Plasma Progesterone Concentrations in Pregnant Ewes

1974 ◽  
Vol 27 (6) ◽  
pp. 659 ◽  
Author(s):  
AR Gleeson ◽  
GD Thorburn
Keyword(s):  
Protein Binding ◽  
Diurnal Variation ◽  
Significant Positive Correlation ◽  
Plasma Samples ◽  
Elevated Plasma ◽  
Progesterone Concentration ◽  
Plasma Progesterone ◽  
Blood Samples ◽  
Peripheral Plasma ◽  
Competitive Protein Binding

A competitive protein-binding technique was used to measure progesterone concentrations in the peripheral plasma of pregnant ewes. Neither haemolysis of blood nor thawing of plasma samples affected plasma progesterone concentration. Blood samples should be chilled immediately upon collection but subsequent to centrifugation immediate chilling of the plasma samples is not critical. No consistent diurnal variation in progesterone concentrations was evident but there was large apparently random day-to-day variation in progesterone concentrations for any ewe. Although a significant positive correlation was found between endogenous progesterone and corticosteroid concentrations, the present study failed to correlate experimentally elevated plasma corticosteroid concentrations with progesterone concentrations. Progesterone concentrations varied greatly between ewes at the same stage of pregnancy.

Endogenous ultradian rhythms in rats exposed to prolonged continuous light

1978 ◽  
Vol 235 (5) ◽  
pp. R250-R256 ◽  
Author(s):  
K. I. Honma ◽  
T. Hiroshige
Keyword(s):  
Circadian Rhythm ◽  
Locomotor Activity ◽  
Body Temperature ◽  
Circadian Rhythms ◽  
Continuous Light ◽  
Plasma Corticosterone ◽  
Ultradian Rhythm ◽  
Ultradian Rhythms ◽  
Serial Sampling ◽  
Free Running

Circadian rhythms of locomotor activity, body temperature, and plasma corticosterone were determined simultaneously in individual rats that were exposed to 200 lx continuous light for over 3 mo. Free-running circadian rhythms of locomotor activity persisted for about 2 mo under continuous light and then the rhythms gradually decomposed. After 3 mo of exposure, circadian rhythms disappeared and activity bursts of 1- to 2-h duration manifested themselves several times during a 24-h period. Body temperature also exhibited several bursts of fluctuation and these bursts were closely correlated in their temporal sequence with those of locomotor activity. A least-squares spectrum analysis revealed that the burst had regular 4- to 6-h periods. Plasma corticosterone, determined by serial sampling at 2-h intervals from individual rats, also exhibited several secretion episodes in a day. These episodic secretions synchronized with bursts of locomotor activity. These results suggest that the ultradian component, manifested under prolonged continuous light, is a fundamental unit of the circadian rhythm and an oscillator for the ultradian rhythm is common to the three functions examined.

scholarly journals Assessment of a Simple Competitive Protein-Binding Technique for Plasma Cortisol Assay

1975 ◽  
Vol 12 (1-6) ◽  
pp. 66-69 ◽  
Author(s):  
Mary F. Crowley ◽  
Katherine J. T. Garbien ◽  
J. W. Tuttlebee
Keyword(s):  
Protein Binding ◽  
Plasma Cortisol ◽  
Late Pregnancy ◽  
Plasma Samples ◽  
Blood Samples ◽  
Prednisolone Therapy ◽  
Dexamethasone Therapy ◽  
Competitive Protein Binding ◽  
Synthetic Steroids ◽  
Significant Interference

The Cortipac kit for Cortisol assay by a competitive protein-binding technique (CPB) which utilizes 75Se Cortisol has been evaluated. Results obtained by it agree well with those by the Mattingly fluorimetric method. Assays can be carried out on either plasma or serum and haemolysis does not interfere. The specificity of the assay was checked in blood samples from patients receiving synthetic steroids. Prednisone and prednisolone therapy caused significant interference with the assay; fluorocortisol and dexamethasone therapy did not. The increased progesterone in late pregnancy blood samples had only a small effect on the assay. Plasma samples for Cortisol assay could be stored for at least 4 weeks at 4°C and for at least 12 weeks at −20°C.

A COMPARISON OF THE COMPETITIVE PROTEIN-BINDING ASSAY AND RADIOIMMUNOASSAY FOR PLASMA PROGESTERONE DURING THE NORMAL MENSTRUAL CYCLE

1972 ◽  
Vol 54 (3) ◽  
pp. 445-456 ◽  
Author(s):  
CHRISTINE A. MORGAN ◽  
I. D. COOKE
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Protein Binding ◽  
Bovine Serum ◽  
Binding Assay ◽  
Plasma Samples ◽  
Plasma Progesterone ◽  
Protein Binding Assay ◽  
Competitive Protein Binding ◽  
Free Steroid

SUMMARY A protein-binding assay for plasma progesterone using 2% aqueous chick plasma as the binding solution is described. Details of specifications for petroleum spirit to extract the plasma are given, no chromatographic step being employed. Bound and free steroid are separated by Florisil. The system will assay plasma progesterone at a concentration of 2·0 ng/ml; other reliability data are evaluated. One technician can assay 12 duplicate plasma samples per day. The radioimmunoassay method has utilized two antisera, the first, antiprogesterone-20-0-carboxymethyl-oxime—bovine serum albumin at a dilution of 1 in 3000, the second, anti-progesterone-11-succinyl—bovine serum albumin at a dilution of 1 in 10000. Bound and free steroid are separated by dextran—charcoal suspension. The system will assay plasma progesterone at a concentration of 1·0 ng/ml. One technician can assay 24 duplicate plasma samples per day. There is a good correlation between results obtained by both competitive protein-binding (CPB) and radioimmunoassay (RIA) methods. Both methods have a place in estimating the large numbers of serial samples required in the study of physiological situations, although the RIA method will probably supersede the CPB because of its robustness and greater output.

A SIMPLE COMPETITIVE PROTEIN-BINDING ASSAY FOR ADENOSINE-3′,5′-MONOPHOSPHATE IN PLASMA AND URINE

1976 ◽  
Vol 81 (1) ◽  
pp. 208-214 ◽  
Author(s):  
S. Nistrup Madsen ◽  
I. Badawi ◽  
L. Skovsted
Keyword(s):  
Protein Binding ◽  
Binding Assay ◽  
Plasma Samples ◽  
Protein Binding Assay ◽  
Urinary Content ◽  
Competitive Protein Binding Assay ◽  
Competitive Protein Binding ◽  
The Mean

ABSTRACT A modified competitive protein-binding assay for the measurement of adenosine-3′,5′-monophosphate is desribed. The procedure allows measurement of adenosine-3′,5′-monophosphate in unextracted plasma samples. The mean plasma values in 25 normal, fasting and ambulatory subjects were 22.7 ± 4.7 pmol/ml (mean ± sd) (range 13–31 pmol/ml. The mean urinary content was 3.2 ± 1.0 μmol per g creatinine (mean ± sd) (n=24).

Evaluation of a Serum/Plasma Separator: Suitability of Samples for Radioimmunoassay and Competitive Protein Binding Techniques

1976 ◽  
Vol 13 (1-6) ◽  
pp. 449-451
Author(s):  
Katherine J. T. Garbien ◽  
J. W. Tuttlebee ◽  
Mary F. Crowley
Keyword(s):  
Growth Hormone ◽  
Protein Binding ◽  
Whole Blood ◽  
New Method ◽  
Plasma Samples ◽  
Competitive Protein Binding

A new method of separating serum or plasma from whole blood (Sure-Sep, W. R. Warner) has been evaluated with particular regard to the suitability of the serum/plasma samples for radioimmunoassay (R.I.A.) and competitive protein binding (C.P.B.) techniques. Sure-Sep did not affect the results obtained for the following assays: cortisol, thyroxine, triidothyronine, insulin, and growth hormone. In addition it was also found that contact of the serum or plasma samples with Sure-Sep for 24 hours at 4°C was without effect on the results obtained.

BOVINE PLASMA OESTROGENS, PROGESTERONE AND GLUCOCORTICOIDS DURING DEXAMETHASONE INDUCED PARTURITION

1976 ◽  
Vol 81 (2) ◽  
pp. 385-397 ◽  
Author(s):  
L. E. Evans ◽  
W. C. Wagner
Keyword(s):  
Protein Binding ◽  
Plasma Samples ◽  
Plasma Progesterone ◽  
Peripheral Plasma ◽  
Progesterone Production ◽  
Bovine Plasma ◽  
Competitive Protein Binding ◽  
Pre Treatment

ABSTRACT Plasma samples were collected from jugular, uterine and utero-ovarian veins during glucocorticoid induced parturition. Plasma oestrogens, corticosteroids and progesterone were determined by competitive protein binding methods. Corticosteroids and progesterone began to decline within 8 to 10 h following DXMS treatment. Corticoids were only temporarily suppressed, while progesterone fell to minimum levels and remained low through calving. At this stage of gestation (270 days) peripheral plasma progesterone was primarily of ovarian origin. Pre-treatment with HCG appeared to support progesterone production by the CL despite DXMS treatment in 2 of 6 cows. These 2 cows failed to calve within the expected 96 h after DXMS. Plasma oestrogens did not show significant increases until 24 h after DXMS treatment. Cows which responded to DXMS treatment (calved) had significantly higher oestrogen levels than those which did not respond. It was concluded that oestrogens probably play a permissive rather than an initiating role in parturition.

EVALUATION OF A SIMPLIFIED METHOD FOR DETERMINING SERUM THYROXINE BY COMPETITIVE PROTEIN BINDING ANALYSIS

1970 ◽  
Vol 64 (4) ◽  
pp. 630-636 ◽  
Author(s):  
Stephen C. Thorson ◽  
Ronald Tsujikawa ◽  
James L. Brown ◽  
Robert T. Morrison ◽  
Hamish W. McIntosh
Keyword(s):  
Protein Binding ◽  
Clinical Application ◽  
Thyroid Status ◽  
Serum Thyroxine ◽  
Binding Analysis ◽  
Simplified Method ◽  
Competitive Protein Binding ◽  
Hypothyroid Patients

ABSTRACT Serum thyroxine concentrations were determined in 66 euthyroid, 30 hyperthyroid and 13 hypothyroid patients using both the established Murphy method and a simplified method of competitive protein binding analysis. A diagnosis compatibility of 96% was found with both methods indicating that the simplified method has comparable clinical application as an initial screen of thyroid status.

Sign in / Sign up

Export Citation Format

Share Document