3-Dimensional anatomic relationship of serotonergic and muscarinic receptor binding in the pontine reticular formation of the human infant brainstem

The present trial deals with the effects of birth stress on the thyreoidea respectively on the thyroxine- and triiodthyronine-concentration as well as on their unbound fraction (FT4 and FT3) of suckler calves and the evolution of those parameters in the first three months of life. T4- and T3 concentrations in blood serum of calves were beyond maternal levels increasing significantly in the first 24 hours with strong individual specificity and reaching levels of adult animals at the end of the three-month-period. The different increasing rates of the four parameters show a stimulation of the thyreoideal activity and of the monodejodinase-system as well and they show also a greater decomposition rate of the binding proteins. An influence of the course of parturition on the T3 level p.n. and the T4/T3 ratio in the first 24 hours could be disclosed. The hormone concentrations p.n. showed correlations to the pH and pCO2 of the neonatal calves. For T4 and T3 a strong influence of maternal levels on the hormone levels of the calves p.n. could be ascertained. Effects of breed, surrounding temperatures and type of husbandry on the investigated parameters could be established.     

Thyroid hormones in dairy calves after birth and in the first days of life. Amplitude of variation, maternal-fetal relationships and reaction patterns specific to the individual

Dairy calves and their dams from the dairy herd of the institute were used for this investigation. Calvings were watch carefully and jugular venous blood samples taken immediately after delivery from the cow and the calf and in the calf at 24 hours and at 48 hours of postnatal age as well were analyzed for T4, FT4, T3 and FT3 by luminescence enzyme immunoassay (LEIA). Higher thyroid values in calves than in their dams could be found increasing short after birth and reaching their highest level within 24 hours of postnatal life. The individual thyroid hormone values at birth and at 24 hours and at 48 hours of age are well correlated meaning the changes during the first days are specific for each calf. Strong correlation between the thyroid hormone values of the cows and those of the calves could be found. Mean values of thyroid hormones were significantly higher in female than in male calves all time but not different in the dams of these calves.     

Effects of cortisol administration on development of the thyroid and adrenal axes in rats

Intraperitoneal (IP) injections of cortisol were administered to neonatal male rats on postnatal days 1 to 4. Plasma triiodothyronine (T3), thyroxine (T4) and corticosteroids were determined on days 5, 10, 13, 16, 20, 30 and 60 of age, and all animals were weighed weekly. Neonatal cortisol treatment resulted in depressed body weight gain and transient depression in plasma T4. These results indicate that while body weight is significantly affected by cortisol treatment ontogenic patterns of plasma T3, T4 and corticosteroids develop normally.     

Effects on cattle of transport by road for up to 15 hours

Twenty-four castrated male cattle aged between 12 and 18 months were transported by road for five, 10 or 15 hours, over distances of 286, 536 and 738 km. Half the animals were of Hereford x Friesian breeding and half of 'continental' type. The animals transported for five hours lost 4.6 per cent of their bodyweight, those transported for 10 hours lost 6.5 per cent and those transported for 15 hours lost 7.0 per cent; recovery to pre-transport values took five days. There was little evidence from changes in blood composition that a 15-hour journey was more stressful than a 10-hour journey. The cortisol concentrations were increased by the stresses of loading and the first part of the journey but then recovered as the journey continued. Creatine phosphokinase (CPK) activities increased progressively with the longer journeys and CPK, urea, albumin and osmolality levels recovered more slowly after the longer journeys. Increases in free fatty acids, beta-hydroxybutyrate and urea concentrations and the continued increase in urea levels after the end of the journeys suggested that the animals' normal pattern of feeding was disrupted. Increases in albumin, total plasma protein and osmolality indicated slight dehydration during transit which was quickly rectified by access to water. The two breed types responded similarly to transport, except that the increases in CPK were greater in the continental breeds, possibly as a result of their greater muscularity or greater sensitivity to stress. Based on the physiological measurements made and the subjective observations of behaviour a 15-hour transport period under good conditions is not unacceptable from the viewpoint of animal welfare.     

The kinetics in vivo of the synthesis of albumin-like protein and albumin in rats

The incorporation of radioactivity into total protein, albumin-like protein and albumin in liver and into total protein and albumin in blood plasma, was studied for a time period of 2 h after intraportal injection of L-[1-14C]leucine. 1. In the liver, radioactivity began to increase in albumin-like protein before 2.5 min and in albumin at about 10 min after injection. In the plasma, radioactive albumin appeared at about 15 min. No albumin-like protein could be detected in the plasma. 2. Maximum radioactivity was reached first in albumin-like protein, then in hepatic albumin and finally in albumin in the blood-stream. The maximum specific radioactivity of albumin-like protein was 15 times higher than that of extravascular hepatic albumin which, in turn, was 6 times higher than that of plasma albumin. 3. The increase of radioactivity in albumin in the blood corresponded almost quantitatively to the decrease of radioactivity in albumin-like protein. 4. It is concluded that the albumin-like protein is the precursor of albumin in vivo. It is converted into albumin 5-6 min before the appearance of newly synthesized albumin in the blood-stream.     

Identifying hospitalized older patients at varying risk for physical performance decline: a new approach

It is not known how immaturity and disease influence postnatal thyroid function in infants <30 wk of gestational age. We performed serial measurements of plasma thyroxine (T4), free T4 (FT4), triiodothyronine (T3), reverse T3 (rT3), TSH, and T4-binding globulin (TBG) in 100 infants of <30 wk of gestation, during the first 8 postnatal weeks, to investigate the influences of disease and gestational age on the time course of thyroid hormones. One hundred infants were divided twice into two groups: 1) in a group of 25-28 and of 28-30 wk of gestation; and 2) in a sick and a healthy group, with similar gestational ages. The time course of T4, FT4, T3, TSH, and TBG, but not rT3 differed significantly (p < 0.005) between the gestational age groups. T4 and FT4 decreased to levels below the cord blood value with a deeper FT4 nadir on d 7 in the youngest group. Disease decreased T4, FT4, T3, TSH, and TBG concentrations especially during the 1st wk after birth (p < 0.005). However, the FT4 nadir on d 7 was similar in sick and healthy infants. After 3 wk, T4, FT4, T3, and TBG were higher in the sick group compared with the healthy group. rT3 levels were not increased in sick infants. We conclude that the extent of the FT4 decrease after birth in infants of <30 wk gestation is mainly influenced by gestational age and probably reflects a transient depletion of thyroidal hormone reserves. rT3 cannot be used as a marker of nonthyroidal illness in very preterm infants.     

The influence of transportation stress on selected nutritional parameters to establish the necessary minimum period for adaptation in rat feeding studies

The optimal length of the adaptation period after transportation of rats, to be used in nutritional studies, was investigated in this study. After intracontinental transportation of rats by car and by air to and from the laboratory for a total period of 15 h, measurements were carried out for a period of 3 weeks after transport. Control and transported animals were housed in the same laboratory before and after transportation. During transport the animals had access to food and water. As blood collection could also cause stress, a factorial design was carried out with transport and blood collection as main factors. Transport or blood collection did not cause significant effects on the following parameters: body weight, growth, clinical observation, and blood enzyme activities of LDH and ASAT. Water intake was significantly increased after transport. Food intake did not show consistent effects after transport or blood collection. Unexpectedly, blood corticosterone levels were significantly lower in the transported animals at day 1 after transport. After 3 days these levels were back to normal. Blood glucose, blood free fatty acids and blood urea nitrogen concentrations were incidentally decreased, whereas total cholesterol levels showed an incidental rise in the transported rats. The open-field behaviour test revealed no clear-cut results concerning the effects of transport or blood collection on faeces production, rearing and ambulation. Our results indicate that after intracontinental transport, an adaptation period of 3 days appears to be sufficient for rats to be used in nutritional studies.     

Composition of peripheral blood progenitor cell components collected from healthy donors

OBJECTIVES: The purpose of this study was to test the hypothesis that low circulating thyroxine concentrations characteristic of very low birth weight (VLBW) neonates (< 1500 g) are the result of decreased protein binding of thyroid hormones and to elucidate the mechanism(s) responsible and possible significance thereof. DESIGN: Cross-sectional comparison of thyroid related measurements in cord blood specimens from VLBW infants and from full term infants. Longitudinal comparison in cord and 2- and 4-week blood specimens from VLBW infants. PATIENTS: Cord blood specimens were analysed from 47 VLBW and 45 full term infants weighing > or = 2500 g. Repeat analyses in venous bloods from 32 of the VLBW infants were analysed at 2 weeks of age and again at 4 weeks in 23. The first cohort of patients was studied in 1994 and comprised 28 VLBW and 24 full term infants (Cohort A). The studies were repeated in 1995-96 in 19 VLBW infants and 21 full term infants (Cohort B). MEASUREMENTS: T4, free T4 (FT4), T3, thyroxine binding globulin (TBG), and TSH were measured in cord blood and 2- and 4-week venous specimens from VLBW infants and in cord blood specimens of full term infants. Molar ratios of T4/TBG were calculated. RESULTS: (1) Cord blood TBG, T4 and T3 concentrations of VLBW infants were each 60% of those of term infants. TBG concentrations were 397 +/- 111 vs 680 +/- 172 nmol/l (P < 0.0005). T4 concentrations were 76 +/- 22 vs 139 +/- 26 nmol/l (P < 0.0005). FT4 concentrations were in the normal adult range in both neonatal groups. T4/TBG ratios did not differ between the neonatal groups but were significantly less than that of adults (P < 0.001). (2) TSH concentrations in VLBW infants at 2 and 4 weeks were less than 50% of cord blood values. At 2 weeks, TBG concentrations of VLBW infants were unchanged from cord blood concentrations but mean T4 concentration fell by 18% and T4/TBG ratios by 21% (P < 0.005). Mean FT4 rose by 78% (P < 0.02). The changes in mean T4 and FT4 were due largely to FT4 concentrations of 37-113 pmol/l and T4 concentrations of 13-48 nmol/l in 5 infants. These infants also had lower T4/TBG ratios and were smaller and more ill than the remainder of the cohort. The changes disappeared by 4 weeks in 3 of the 4 infants tested. CONCLUSIONS: Cord T4/TBG ratios are the same in very low birth weight and term infants and are significantly lower than in adult blood. These are more than compensated for in term infants by a 236% increase in thyroxine binding globulin concentrations. The lower thyroxine binding globulin concentrations in very low birth weight infants explain their much lower T4 concentrations. Cord FT4 concentrations of full term and very low birth weight infants are in the normal adult range. T4 concentrations are further depressed and free T4 concentrations elevated in the most ill very low birth weight infants at 2 weeks of age in a manner analogous to that of the 'sick euthyroid syndrome'.     

Late outcome of amputees with premature atherosclerosis

Plasma free T4 (FT4) concentrations could be increased during hemodialysis in patients with chronic renal failure (CRF) because an increase in non-esterified fatty acids (NEFA) could interfere with the binding of T4 to thyroxine-binding globulin. To evaluate the effect of hemodialysis on the FT4 concentration in patients with CRF, we measured the FT4 in 39 patients with CRF by four assay methods including equilibrium dialysis, the 125I-T4 analog method and enzyme immunoassay. The addition of the fatty acid sodium oleate to normal pooled sera led to a marked increase in FT4 as measured by equilibrium dialysis (Model FT4). A moderate increase in the serum FT4 concentration also was observed with an IMX enzyme immunoassay kit, whereas the Coat-A-Count analog method demonstrated no interference by sodium oleate. The mean serum FT4 prior to hemodialysis measured by equilibrium dialysis did not differ significantly from that in the normal control, although those measured by analog methods (Coat-A-Count and Amerlex) and IMX were subnormal. The FT4 by IMX were albumin-dependent, and the values decreased as the samples were serially diluted, but Model FT4 was not affected by the albumin level or the serial dilution. FT4 by Model FT4 showed a marked increase beginning 10 min after the start of dialysis, and it correlated well with the plasma concentration of NEFA and the NEFA/albumin molar ratio. The other three assay methods, including one which is not affected by NEFA, did not show a change in FT4 at 10 min, but a significant increase of 11 to 17% was observed by the end of dialysis. The TSH concentration decreased significantly during hemodialysis. These data suggest that (1) the low serum FT4 in hemodialysis patients measured by some immunoassay methods may be an underestimation due to the low albumin level; (2) FT4 actually increases during hemodialysis due to the actual increase in NEFA, although the marked increase in FT4 during hemodialysis as measured by equilibrium dialysis is an overestimation due to the in vitro generation of NEFA; and (3) one should beware of aberrations in thyroid hormone parameters during hemodialysis and potential complications.     

Genetic variation within the Hereford breed of cattle

Genetic differentiation among Hereford populations from Britain, Ireland, Sweden, Canada and New Zealand together with six other beef breeds was assessed using blood type polymorphisms. Changes in the genetic structure of the British Hereford population over time were also examined. Loci surveyed were seven red cell antigen systems (A, B, C, F, L, S, Z), and two serum protein loci (transferrin and albumin). Within group variation was measured by the average expected heterozygosity, and between group relationships by genetic distance. There was significant genetic differentiation among Hereford populations from different countries. Differences between Hereford groups, however, were not as large as differences between breeds. There were also significance differences among British herds. The proportion of Canadian genes in the British 'hybrid' population was estimated to have increased from 0.42 (+/- 0.34) in the 1970s to 0.98 (+/- 0.11) in the 1990s. Canadian Hereford groups were found to be less heterozygous than other groups, and replacement of the British population with Canadian animals may lead to loss of variation. Breeding strategies that preserve original native genes in British Hereford populations should be considered by commercial breeders, in order to prevent the long-term loss of genetic variation within the breed.     

A further investigation of basal HPT axis function in unipolar depression: effects of diagnosis, hospitalization, and dexamethasone administration

Hypothalamic-pituitary-thyroid (HPT) axis function was assessed in depressed subjects 1 and 8 days after hospital admission, and after the administration of 1 mg of dexamethasone. Plasma levels of thyroid stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) were measured by ultrasensitive assays in 16 patients with minor depression, 15 patients with simple major depression, and 13 patients with melancholia. The postdexamethasone adrenocorticotropic hormone (ACTH) (intact 1-39 molecule) and cortisol values were determined. Basal TSH values were significantly lower in melancholic patients than in patients with minor and simple major depression on the day after admission and 1 week later. Basal TSH values determined 1 week after admission were significantly and negatively related to FT4 values and severity of depression. There were no significant differences in basal TSH, FT3, and FT4 values obtained on day 1 and day 8 after hospital admission. Dexamethasone administration had a significant suppressant effect on basal TSH and FT3 values. Patients who failed to suppress cortisol after the dexamethasone suppression test (DST) exhibited significantly less suppression of basal TSH values than did DST cortisol suppressors.     

Effects of the Iditarod Sled Dog Race on serum thyroid hormones and body composition

Cold exposure, activity and energy deficit have been associated with changes in body composition and/or changes in serum thyroid hormones. Because these conditions are present during the Iditarod Sled Dog Race, 10 volunteer participants were studied before and after the race. Body composition, total thyroxine (TT4), free thyroxine (FT4), total triiodothyronine (TT3), and free triiodothyronine (FT) levels were determined. There was a significant decrease in body weight (p < 0.05) and a decrease in body fat (p < 0.01). There were no significant changes in TT4, FT4, TT3 or FT3. On the basis of this study, it can be concluded that the strenuous activity of the Iditarod mitigates against the classic perturbation in thyroid axis brought on by the hypocaloric state.     

Time course of changes in free thyroid indices, rT3, TSH, cortisol and ACTH following exposure to sulfur mustard

In order to evaluate the time course of changes in serum concentration of thyroid hormones, cortisol and ACTH in patients exposed to chemical weapons containing sulfur mustard, we measured serum concentrations of hormones on the first, third and fifth week following injury in 13 soldiers and compared them to the results obtained from 34 control men. Free T4 and T3 indices were decreased and rT3, cortisol and ACTH were increased in the first week following exposure. There was a subnormal TSH response to TRH in 2 of 3 men tested. Except for an increase in FT4I and a decrease in TSH by the third week, and a steady decline in serum cortisol, serum hormone concentrations were unchanged until the fifth week after injury. The decline in serum cortisol occurred despite a constant increase in serum ACTH. By the fifth week only 1 of 13 men had serum cortisol levels > 10 micrograms/dl. We conclude that exposure to chemical weapons containing sulfur mustard results in alterations in serum concentrations of thyroid and adrenal hormones and ACTH, resembling changes seen in burn trauma. Some evidence of direct effects of mustard on endocrine glands exist.     

Opioid requirements and responses in Asians

BACKGROUND: There is a relationship between stressful situations and the susceptibility towards certain diseases, probably mediated by immune system modifications. AIM: To study T lymphocyte proliferation in medical students during periods of differing academic stress. SUBJECTS AND METHODS: Blood samples were obtained from 42 medical students during a period of moderate academic stress, immediately before a final examination and after their summer vacations. T lymphocyte proliferation in response to 5, 10 and 20 mg/ml phytohemagglutinin was measured by the incorporation of 3H-thymidine, and plasma cortisol was measured by RIA. RESULTS: T lymphocyte stimulation index in response to all phytohemagglutinin concentrations was significatively lower in the period before examination than in the other two periods. There were no differences in the index between the period of moderate stress and after summer vacations. Plasma cortisol levels were 15.6 +/- 4.3, 18.6 +/- 5.8 and 16.7 +/- 5.1 mg/dl during the periods of moderate stress, before the examination and after vacations, respectively (p < 0.05 for the difference between examination and the other two periods). CONCLUSIONS: There is a decrease in lymphocyte proliferation and an increase in cortisol levels during a period of acute academic stress in medical students, suggesting that, the exposure of the healthy subjects to common stressful stimuli, may affect their immunocompetance.     

Claw lesions in dairy cattle: development of sole and white line haemorrhages during the first lactation

To assess the role of genetic changes in sensitivity to leptin hormone in contributing to responses to long-term selection for fatness, leptin was administered to a long-term fat selected (F) and a control line (C) of mice. These lines differ almost three fold in their percentage of fat (fat%) at about 15 weeks of age. Treated (T) animals received twice-daily intraperitoneal injections of 5mg/kg leptin from 91 to 105 days of age; untreated (U) animals received equivolume injections of phosphate-buffered saline. Treated compared with untreated animals in both lines had significantly (P < 0.05) lower mean body weight, food intake and fatness at the end of test (fat%: CT 3%, CU 7.4%, FT 14.9%, FU 21.1%). The differences in response between the lines [(CT-CU)-(FT-FU)] were all non-significant (P > 0.05), however. There was a very wide range of fatness (estimated from dry matter content) among FT animals (3-29%), much higher than in FU (15-31%), CT (0.7-6.4%) and CU (2-15%) animals. While sensitivity to leptin remains in the fat line, response appears to vary among animals at the dose level used.     

Effects of oral administration of anti-inflammatory doses of prednisone on thyroid hormone response to thyrotropin-releasing hormone and thyrotropin in clinically normal dogs

Prednisone was given orally to 12 dogs daily for 35 days at an anti-inflammatory dosage (1.1 mg/kg of body weight in divided dose, q 12 h) to study its effect on thyroxine (T4) and triiodothyronine (T3) metabolism. Six of these dogs were surgically thyroidectomized (THX-Pred) and maintained in euthyroid status by daily SC injections of T4 to study peripheral metabolism while receiving prednisone; 6 dogs with intact thyroid gland (Pred) were given prednisone; and 6 additional dogs were given gelatin capsule vehicle as a control group (Ctrl). Baseline T4 concentration after 4 weeks of treatment was not significantly different in dogs of the THX-Pred or Pred group (mean +/- SEM, 2.58 +/- 0.28 or 3.38 +/- 0.58 micrograms/dl, respectively) vs dogs of the Ctrl group (2.12 +/- 0.30 micrograms/dl). A supranormal response of T4 to thyrotropin was observed in dogs of the Pred group, but the T4 response to thyrotropin-releasing hormone was normal. Baseline T3 concentration in dogs of both steroid-treated groups was significantly (P < 0.05) lower after 2 and 4 weeks of prednisone administration vs pretreatment values, but normalized 2 weeks after prednisone was stopped. Free T3 (FT3) and T4 (FT4) fractions and absolute FT3 and FT4 concentrations were not altered by prednisone administration. Reverse T3 (rT3) concentration in vehicle-treated Ctrl dogs (26.6 +/- 3.5 ng/dl) was not different from rT3 concentration in dogs of the THX-Pred (25.7 +/- 4.3 ng/dl) and Pred (28.9 +/- 3.8 ng/dl) groups after 4 weeks of medication.(ABSTRACT TRUNCATED AT 250 WORDS)     

Thyroid hormone changes in a cold air environment after local cold acclimation

Serum thyroid hormones (TH) and internal temperatures were investigated in 8 euthyroid men during a general standard cold air test (SCAT) (dry bulb temperature = 1 degree C, 2 h, nude, at rest) performed both before and after a local cold acclimation. Serum total thyroxin (TT4), total triiodothyronine (TT3), free thyroxin (FT4), free triiodothyronine (FT3), and thyrotropin (TSH) were studied during the SCT. The TH values were corrected following the plasmatic volume reduction (delta PV) calculated with Dill and Costill's formula. During SCAT, delta PV reached -9 to -11% (P < 0.05) without any effect of local cold acclimation. Slight TH changes were observed according to delta PV: TT4, TT3, and TSH increased during SCAT (P < 0.05) only before correction. FT4 and FT3 did not vary before correction but increased after correction (P < 0.05). After acclimation, a slightly decreased TT3 was observed both before and after correction (-18% and -11.7%, respectively; P < 0.05). Decreased internal temperatures after local cold acclimation suggested a hypothermic general cold adaptation. It was concluded that TH changes during SCAT differed if correction due to delta PV was applied and that the slight decrease in TT3 observed after local cold acclimation could suggest the presence of a "T3 polar syndrome."     

Adrenal responses of Angus x Hereford cattle to the stress of weaning

To test adrenal responsiveness of beef cattle to stress, plasma norepinephrine, epinephrine, and cortisol responses of Angus x Hereford cattle to weaning were measured in blood samples taken from 1) eight cows and their 4- to 6-mo-old calves before and after separation and, the following day, before and after being reunited and 2) an equal number of control animals. After separation and before they were reunited, dams were returned to their original pen and calves to an adjacent pen. Experimental trials were conducted every 2 wk and included two cow/calf pairs per trial. Norepinephrine concentrations tended to increase in calves after separation, were increased (+82 pg/mL, P < .01) on the 2nd d before animals were reunited, and decreased (-88 pg/mL, P < .01) after animals were reunited. Epinephrine concentrations tended to increase in calves after separation, were increased in calves (+128 pg/mL, P < .001) and dams (+104 pg/mL, P < .001) on the 2nd d before animals were reunited, and decreased after calves (-162 pg/mL, P < .001) and dams (-101 pg/ml, P < .001) were reunited. There were no significant effects of time on catecholamine concentrations for control animals. Cortisol concentrations for treated and control animals tended to increase in sequential samples each day; however, the increases were small (approximately 1 ng/mL) and concentrations remained low (> 5 ng/mL). In conclusion, peripheral catecholamine concentrations in beef calves and epinephrine concentrations in dams increased in response to stress associated with weaning and separation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hypothalamic-pituitary-adrenal function one week after a short burst of steroid therapy

"Steroid burst therapy" is commonly used for various acute medical conditions, but its suppressive effect on hypothalamic-pituitary-adrenocortical (HPA) function and the time period for recovery of HPA function is not fully known. We therefore evaluated the HPA function in 10 normal adults before and after a short burst of Prednisone (40 mg/three times daily for 3 days, then tapered over the next 4 days). HPA function was evaluated by iv administration of 100 micrograms of ovine CRH (oCRH) and blood samples for ACTH and cortisol assay were obtained at -30,0,10,15,30,60,90, and 120 min. On another day, 250 micrograms synthetic ACTH (Cosyntropin) were given iv and blood samples for cortisol were obtained at 0,30,60, and 90 min. Basal and peak levels of ACTH and cortisol before and 1,2, and 3 weeks after discontinuation of prednisone in response to oCRH iv are shown below (see Table 1). All values are mean (SEM). Peak levels of cortisol after iv administration of Cosyntropin at week 0 were 922(56.8), week 1 899(63.7), week 2 861(70.9), and week 3 855(53.0). There was no significant difference noted in the levels of ACTH and cortisol in response to oCRH before and after prednisone treatment. Pre- and posttreatment responses of cortisol to Cosyntropin administration were also similar. In addition, cumulative responses (area under the curve) and the change from baseline (delta) before and after administration of prednisone were similar for ACTH and cortisol. We conclude that HPA function is normal 1 week after discontinuation of a short burst of prednisone. These findings suggest that administration of additional steroids may not be required during periods of "stress" for those patients who have previously received similar steroid burst therapy, if at least 1 week has elapsed after such treatment was given.     

Serum concentrations of thyroid hormones during egg laying in two types of Japanese quail (Coturnix coturnix japonica)

In the present investigation a lighter white egg-type (L) and a heavier wild meat-type (M) of female Japanese quails were compared with respect to egg production, body growth, abdominal fat pad, serum thyroxine (T4) and triiodothyronine (T3) concentrations, TRH sensitivity and T4 5'-monodeiodinase activity in liver homogenates. During the investigation period L type layed considerably more eggs and M type was heavier in body weight. Abdominal fat pad in L type quails was significantly higher than in M type ones. L type quails had lower serum T4 and T3 concentrations than M type ones and the liver T4 5'-monodeiodinase activity was higher in M type than in L type quails. Following TRH administration serum T4 and T3 concentrations increase was higher in L type quails than in M type ones. Our results suggest that lower T4 and T3 observed in L type quails reflect a possible metabolic adaptation to egg production. Different activities of 5'-monodeiodinase and of response to TRH may be inherent to these two types of quail.