CHANGES IN CORTISOL BINDING AND METABOLISM DURING NEONATAL DEVELOPMENT IN THE GUINEA-PIG

1980 ◽  
Vol 85 (2) ◽  
pp. 219-227 ◽  
Author(s):  
M. DALLE ◽  
A. EL HANI ◽  
P. DELOST
Keyword(s):  
Guinea Pig ◽  
Clearance Rate ◽  
Guinea Pigs ◽  
Surgical Stress ◽  
Binding Capacity ◽  
Post Partum ◽  
Metabolic Clearance ◽  
Metabolic Clearance Rate ◽  
Male And Female ◽  
Free Cortisol

The metabolic clearance rate and the binding of cortisol in plasma of male and female guinea-pigs were estimated at five stages between birth and weaning. The metabolic clearance rate for cortisol remained low in both sexes until day 10 post partum but increased to adult values by day 20. The level of free cortisol in plasma and the cortisol binding capacity of the plasma were higher at birth than on day 10 post partum; the values found on day 20 were similar to those of the adult guinea-pig. Surgical stress increased levels of cortisol in plasma on day 20 but not at birth.

CHANGES IN THE METABOLIC CLEARANCE RATE OF PROGESTERONE IN THE GUINEA-PIG

1970 ◽  
Vol 48 (3) ◽  
pp. 409-417 ◽  
Author(s):  
DOREEN V. ILLINGWORTH ◽  
R. B. HEAP ◽  
J. S. PERRY
Keyword(s):  
Plasma Concentration ◽  
Guinea Pig ◽  
Clearance Rate ◽  
Post Partum ◽  
Sharp Decrease ◽  
Metabolic Clearance ◽  
Metabolic Clearance Rate ◽  
High Affinity ◽  
Exogenous Oestrogen ◽  
In Pregnancy

SUMMARY The metabolic clearance rate (MCR) of progesterone was measured by continuous infusion of the tritium-labelled steroid in guinea-pigs under light sodium pentobarbitone anaesthesia. In normal animals during the oestrous cycle, the MCR was 112·8 ± 7·0 (s.e.) 1 plasma/day/kg. In pregnant animals there was a sharp decrease in MCR between days 15 and 20, to 8·3 ± 0·8 1/day/kg. This low clearance rate was observed throughout the remainder of gestation. After parturition MCR returned slowly to non-pregnant levels, reaching 85 1/day/kg by day 12 post partum. The decrease in metabolic clearance rate occurred at the same time as the increase in plasma concentration of progesterone. This may be related to an increase in binding proteins with a high affinity for progesterone. The stimulus for the decrease in MCR in pregnancy is obscure but appears to depend on the presence of a viable conceptus. In the non-pregnant guinea-pig the MCR is not reduced by exogenous oestrogen, hysterectomy or hypophysectomy.

CHANGES IN THE CONCENTRATIONS OF CORTISOL AND CORTICOSTERONE IN THE PLASMA AND ADRENAL GLANDS OF THE GUINEA-PIG FROM BIRTH TO WEANING

1974 ◽  
Vol 63 (3) ◽  
pp. 483-488 ◽  
Author(s):  
M. DALLE ◽  
P. DELOST
Keyword(s):  
Adrenal Gland ◽  
Guinea Pig ◽  
Guinea Pigs ◽  
Plasma Cortisol ◽  
Adrenal Glands ◽  
Post Partum ◽  
Cortisol Secretion ◽  
Male And Female ◽  
Steady Level ◽  
Very High

SUMMARY Concentrations of cortisol and corticosterone in the plasma and adrenal glands of male and female guinea-pigs were estimated throughout the first postnatal day and thereafter at intervals up to 3 weeks of age. In the guinea-pig, the basal level of cortisol secretion is established more slowly than in other species. The concentration of plasma cortisol is very high at birth, with a marked fall between days 1 and 10 post partum and then a steady level from day 10 to 20, the time of weaning. At day 10 the values for plasma cortisol and corticosterone approach the lower ones found in the adult. There were peaks in the amounts of corticosteroids found in the adrenal gland at 50 h, 4 and 7 days and these may have been due to increased hormonal synthesis between days 2 and 8.

FOETAL-MATERNAL PRODUCTION AND TRANSFER OF CORTISOL DURING THE LAST DAYS OF GESTATION IN THE GUINEA-PIG

1979 ◽  
Vol 82 (1) ◽  
pp. 43-51 ◽  
Author(s):  
M. DALLE ◽  
P. DELOST
Keyword(s):  
Guinea Pig ◽  
Clearance Rate ◽  
Transfer Rate ◽  
Plasma Cortisol ◽  
Removal Rate ◽  
The Other ◽  
Metabolic Clearance ◽  
Maternal Origin ◽  
Metabolic Clearance Rate ◽  
Secretory Rate

SUMMARY The metabolism and the rate of transfer of cortisol across the placenta in pregnant guinea-pigs and foetuses were studied by constant intravenous infusions of tritium-labelled cortisol. Estimates of endogenous and radioactive plasma cortisol levels were used to calculate the following parameters at four stages before parturition (days 62, 64, 66 and 67; parturition occurring at day 68): metabolic clearance rate; production rate; adrenal secretory rate; transfer rate from mother to foetus and from foetus to mother; irreversible removal rate; the fraction of cortisol derived from the other in the foetal and maternal vascular compartments; the fraction of secreted and recycled cortisol involved in the transfer. The metabolic clearance rate and the rates of production and secretion of cortisol were higher in the mother than in the foetus between days 62 and 67 of gestation. About 90% of the foetal cortisol was of maternal origin. The fraction of maternal cortisol of foetal origin increased in the last days of gestation.

EFFECTS OF ACUTE NEUROTROPHIC STRESS ON PERIPHERAL METABOLISM OF CORTISOL IN CONSCIOUS MALE GUINEA-PIGS

1981 ◽  
Vol 89 (3) ◽  
pp. 443-449 ◽  
Author(s):  
M. MANIN ◽  
P. DELOST
Keyword(s):  
Adult Male ◽  
Guinea Pigs ◽  
Binding Capacity ◽  
Apparent Volume ◽  
Volume Of Distribution ◽  
Metabolic Clearance ◽  
Control Value ◽  
Cortisol Metabolism ◽  
Free Cortisol ◽  
The Mean

Cortisol metabolism was studied in conscious adult male guinea-pigs subjected to a neurotrophic stress (immobilization and stimulation by light for 3 h). The disappearance curves of tracer quantities of [3H]cortisol were represented by a two-pool model. In stressed animals, there was a marked increase in the mean plasma level of cortisol (184% of control value; P <0·001) and in the metabolic clearance rate (MCR; 17% of control value; 0·001 <P <0·01). This rise in the MCR of plasma cortisol resulted from an increase in the mean total apparent volume of distribution (49%, P < 0·001). The lack of significant differences in the slopes of the second exponential phase of the disappearance curves indicated that the stress did not significantly increase the half-life of cortisol. The mean binding capacity of transcortin for cortisol (ST) was significantly higher in the animals which had been subjected to the neurotrophic stress than in the control guinea-pigs (0·02 < P <0·05). However, ST values remained very low and accounted for the very high levels of free cortisol found after the stress. The results suggest that the raised concentrations of unbound cortisol found in the plasma of conscious adult male guinea-pigs in response to neurotrophic stress reflect a hypersecretion of corticosteroid.

Fetal and maternal production and metabolism of gastrin in sheep

1982 ◽  
Vol 94 (2) ◽  
pp. 183-189 ◽  
Author(s):  
Arthur Shulkes ◽  
Patricia Chick ◽  
K. J. Hardy
Keyword(s):  
Clearance Rate ◽  
Plasma Levels ◽  
Placental Transfer ◽  
Umbilical Vein ◽  
Post Partum ◽  
Metabolic Clearance ◽  
Metabolic Clearance Rate ◽  
Fetal Plasma ◽  
Pregnant Ewe ◽  
Sheep Fetus

In the sheep fetus, plasma levels of gastrin are raised above adult levels from 2 weeks before birth. This observation initiated the present study on the maternal and fetal secretion rate, metabolism and placental transfer of gastrin. The experiments were performed on conscious pregnant ewes with chronically cannulated fetuses and on newborn lambs. Metabolic clearance rate (MCR), production rate (PR) and placental transfer of gastrin were measured by alternate steady-state infusion of gastrin into the mother and fetus. Plasma levels of gastrin were measured by radioimmunoassay. Metabolic clearance rate was similar in the pregnant and non-pregnant ewe (8·4± 1·1 (s.e.m.) and 9·0±1·4 ml/min per kg) respectively. However, fetal MCR was significantly increased. Term was 145 days. Metabolic clearance rate was 15·5 ± 1·7 at 110–125 days of gestation, 25·6 ± 2·9 at 126–135 days, 29·7 ± 4·9 at 136–145 days and remained raised in the first 2 weeks post partum. Gastrin did not cross the placenta in either direction. Placental destruction of gastrin was not responsible for the increased fetal MCR as umbilical artery and umbilical vein levels were not significantly different during fetal gastrin infusion. Furthermore, MCR remained raised in the newborn lambs. Gastrin PR was significantly increased at all ages. The results showed that the previously reported fetal hypergastrinaemia is from fetal sources and is not a result of immaturity of clearance mechanisms. In fact, fetal MCR was significantly increased. The increased fetal plasma gastrin levels are due to an increased rate of production from the fetus.

ROLE OF TESTOSTERONE IN THE SEXUAL DIMORPHISM OF ADRENAL ACTIVITY AT PUBERTY IN THE GUINEA-PIG

1980 ◽  
Vol 87 (3) ◽  
pp. 455-461 ◽  
Author(s):  
A. EL HANI ◽  
M. DALLE ◽  
P. DELOST
Keyword(s):  
Sexual Dimorphism ◽  
Guinea Pig ◽  
Guinea Pigs ◽  
Plasma Cortisol ◽  
Binding Capacity ◽  
Metabolic Clearance ◽  
Response To Stress ◽  
Adrenal Response ◽  
Cortisol Levels

Sexual dimorphism in adrenal activity appeared during the pubertal period of the guinea-pig with plasma levels and binding of cortisol lower in male guinea-pigs compared with female, and metabolic clearance rate (MCR) of cortisol higher in male than in female animals. Gonadectomy of female guinea-pigs did not change the values of the parameters regulating adrenal activity. Castration of male guinea-pigs caused a rise in plasma cortisol levels by increasing the binding capacity of transcortin for cortisol and by decreasing cortisol MCR. Treatment of females with testosterone from day 24 produced a drop on day 50 in plasma cortisol levels following a decreased binding capacity of transcortin for cortisol and at the same time as cortisol MCR increased. Furthermore, the adrenal response to stress was higher in castrated than in control males and lower in testosterone-treated females compared with control females. Testosterone appeared to be the hormone responsible for sexual dimorphism in adrenal activity in the pubertal guinea-pig.

The Metabolic Clearance Rate of and Pressor Responses to Vasopressin in Male and Female Rats*

Endocrinology ◽  
1986 ◽  
Vol 118 (5) ◽  
pp. 1777-1781 ◽  
Author(s):  
JOAN T. CROFTON ◽  
DAVID L. RATLIFF ◽  
DAVID P. BROOKS ◽  
LEONARD SHARE
Keyword(s):  
Clearance Rate ◽  
Female Rats ◽  
Metabolic Clearance ◽  
Metabolic Clearance Rate ◽  
Male And Female ◽  
Male And Female Rats ◽  
Pressor Responses

Effect of Sexual Maturation and Gonadectomy at Sexual Maturity on Cortisol Secretion Rate in Sockeye Salmon (Oncorhynchus nerka)

1970 ◽  
Vol 27 (12) ◽  
pp. 2287-2296 ◽  
Author(s):  
Edward M. Donaldson ◽  
Ulf H. M. Fagerlund
Keyword(s):  
Sexual Maturation ◽  
Clearance Rate ◽  
Sexual Maturity ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Secretion Rate ◽  
Metabolic Clearance ◽  
Cortisol Secretion ◽  
Metabolic Clearance Rate ◽  
Male And Female

Changes in cortisol dynamics in male and female sockeye salmon (Oncorhynchus nerka) have been investigated at various stages during sexual maturation, after spawning, and after gonadectomy just prior to their reaching sexual maturity. The metabolic clearance rate of cortisol was determined by the single injection technique and calculated using the formula for a two-pool system. The volume of distribution of cortisol in the inner pool and the outer pool, metabolic clearance rate, and cortisol secretion rate increased in both male and female salmon during sexual maturation. These changes were reversed in fish that were gonadectomized just before reaching functional maturity and allowed to recuperate for 2 or 8 weeks.There was a decrease in the amount of red carotenoid pigment in the flesh of salmon held in the laboratory during sexual maturation. This loss of pigment was reversed in salmon that were gonadectomized and fed marine zooplankton for 8 weeks.

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