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PubMed1992

Seminal plasma transferrin concentration: relationship with seminal parameters and plasma hormone levels.

Seminal plasma transferrin concentrations were determined in 155 infertile male patients and in 15 pregnancy-proven fertile males (control group); then the relationship between these concentrations and seminal parameters and plasma hormone levels was investigated. The concentrations of seminal plasma transferrin in patients with a sperm concentration below 20 x 10(6)/ml were significantly lower than those in the control group (p < 0.01). There was no significant difference in seminal plasma transferrin concentration between patients with a sperm concentration of 40 x 10(6)/ml or more and the control patients. A positive correlation was observed between sperm concentration and seminal transferrin content (r = 0.56; p < 0.05). However, correlations between seminal transferrin concentration and sperm motility and between seminal plasma transferrin content and sperm morphology did not show any significance, nor did the seminal transferrin content correlate with plasma LH, FSH, prolactin or testosterone levels. It, therefore, seems that while transferrin is indicative of certain physiopathological conditions in the germ cells, this protein is not a distinctive marker of the fertility potential of an individual.

Adult↗
PubMed2000

Plasma levels of extracellular superoxide dismutase in an Australian population: genetic contribution to normal variation and correlations with plasma nitric oxide and apolipoprotein A-I levels.

Extracellular superoxide dismutase (EC-SOD) is a major superoxide scavenger and may be important to normal vascular function and cardiovascular health. We analyzed family data from 610 healthy Australians to detect and quantify the effects of genes on normal variation in plasma levels of EC-SOD and to test for pleiotropy with plasma nitric oxide (NO) and apolipoprotein A-I (apoA-I). Using maximum-likelihood-based variance decomposition methods, we determined that sex, age, and plasma levels of HDL cholesterol, apoA-I, and creatinine accounted for 38.6% of the variance in plasma EC-SOD levels and that additive genes accounted for 35% (P<0.00002). Multivariate analyses of plasma levels of EC-SOD, NO(x) (a measure of basal NO production), and apoA-I detected significant genetic correlations, indicating pleiotropy between EC-SOD and apoA-I (genetic correlation [rho(G)]=-0.45) and between NO(x) and apoA-I (rho(G)=0.58) but not between EC-SOD and NO(x). Genes shared by EC-SOD and apoA-I account for 20% of the genetic variance and, respectively, 7% and 9% of the phenotypic variance in both traits. Shared genes also account for >33% of the genetic variance and 5% and 15% of the respective phenotypic variance in NO(x) and apoA-I. In healthy individuals, over a third of the variance in EC-SOD plasma levels is due to the additive effects of genes. Some genes influence EC-SOD and apoA-I levels. The same is true of NO(x) and apoA-I but not of EC-SOD and NO(x). These patterns of pleiotropy can guide subsequent attempts to identify the genes and physiological mechanisms underlying them.

Adult↗
PubMed1990

Postprandial plasma retinyl ester response is greater in older subjects compared with younger subjects. Evidence for delayed plasma clearance of intestinal lipoproteins.

Postprandial vitamin A and intestinal lipoprotein metabolism was studied in 86 healthy men and women, aged 19-76 yr. Three independent experiments were carried out. In the first experiment, a supplement dose of vitamin A (3,000 retinol equivalents [RE]) was given without a meal to 59 subjects, aged 22-76 yr. In the second experiment, 20 RE/kg body wt was given with a fat-rich meal (1 g fat/kg body wt) to seven younger subjects (aged less than 50 yr) and seven older subjects (aged greater than or equal to 50 yr). In both experiments, postprandial plasma retinyl ester response increased significantly with advancing age (P less than 0.05). In the third experiment, retinyl ester-rich plasma was infused intravenously into nine young adult subjects (aged 18-30 yr) and nine elderly subjects (aged greater than or equal to 60 yr), and the rate of retinyl ester disappearance from plasma during the subsequent 3 h was determined. Mean (+/- SE) plasma retinyl ester residence time was 31 +/- 4 min in the young adult subjects vs. 57 +/- 8 min in the elderly subjects (P less than 0.05). These data are consistent with the concept that increased postprandial plasma retinyl ester concentrations in older subjects are due to delayed plasma clearance of retinyl esters in triglyceride-rich lipoproteins of intestinal origin.

Adult↗
PubMed1999

Daily melatonin administration at middle age suppresses male rat visceral fat, plasma leptin, and plasma insulin to youthful levels.

Human and rat pineal melatonin secretion decline with aging, whereas visceral fat and plasma insulin levels increase. Melatonin modulates fat metabolism in some mammalian species, so these aging-associated melatonin, fat and insulin changes could be functionally related. Accordingly, we investigated the effects of daily melatonin supplementation to male Sprague-Dawley rats, starting at middle age (10 months) and continuing into old age (22 months). Melatonin was added to the drinking water (92% of which was consumed at night) at a dosage (4 microg/ml) previously reported to attenuate the aging-associated decrease in survival rate in male rats, as well as at a 10-fold lower dosage. The higher dosage produced nocturnal plasma melatonin levels in middle-aged rats which were 15-fold higher than in young (4 months) rats; nocturnal plasma melatonin levels in middle-aged rats receiving the lower dosage were not significantly different from young or middle-aged controls. Relative (% of body wt) retroperitoneal and epididymal fat, as well as plasma insulin and leptin levels, were all significantly increased at middle age when compared to young rats. All were restored within 10 weeks to youthful (4 month) levels in response to both dosages of melatonin. Continued treatment until old age maintained suppression of visceral (retroperitoneal + epididymal) fat levels. Plasma corticosterone and total thyroxine (T4) levels were not significantly altered by aging or melatonin treatment. Plasma testosterone, insulin-like growth factor I (IGF-I) and total triiodothyronine (T3) decreased by middle age; these aging-associated decreases were not significantly altered by melatonin treatment. Thus, visceral fat, insulin and leptin responses to melatonin administration may be independent of marked changes in gonadal, thyroid, adrenal or somatotropin regulation. Since increased visceral fat is associated with increased insulin resistance, diabetes, and cardiovascular disease, these results suggest that appropriate melatonin supplementation may potentially provide prophylaxis or therapy for some prominent pathologies associated with aging.

Adipose Tissue↗
PubMed2001

Elevated plasma level of lipotropin revealing an occult carcinoid tumor with normal plasma adrenocorticotropin.

The increases in the level of plasma lipotropin (LPH) and in the LPH/ACTH ratio are considered diagnostic tools in ectopic ACTH syndrome. However, plasma ACTH is also elevated in this syndrome. We report a case of a small carcinoid tumor with an increase in both ACTH and LPH in plasma before surgery. Eight months after the tumoral resection, plasma LPH alone was increased again, whereas plasma ACTH and plasma and urinary cortisol remained normal in this apparently cured patient. This repeated abnormality was the only available feature that allowed successful removal of the occult tumoral residue.

Adrenocorticotropic Hormone↗
PubMed1996

Destabilization of plasma membrane structure by prevention of actin polymerization. Microtubule-dependent tubulation of the plasma membrane.

Electron microscopy of thick (0.2-1.0 micron) sections of cytochalasin D-treated cells fixed in the presence of Ruthenium red revealed an extensive, surface-connected tubular compartment in HEp-2 cells. The tubules measured 120-220 nm in diameter and at least up to 6 microns in length. Morphometric analysis showed that in control cells about 0.2% of the total plasma membrane area (defined as all Ruthenium red-labeled membrane) appeared as vesicular or tubular profiles beneath the cell surface. However, after 15-30 minutes of cytochalasin D incubation about 4% of the total plasma membrane area is tubulated, and after 60-105 minutes as much as about 15% of the total plasma membrane appears as tubules. Clathrin-coated pits and caveolae-like structures were occasionally associated with the tubular membrane. Moreover, immunogold labeling showed that the tubular membrane contained transferrin receptors at about the same density as the nontubulated plasma membrane. Examination of cells in which endosomes and lysosomes were labeled with horseradish peroxidase before or after exposure to cytochalasin D showed that these organelles remained spherical, and that no horseradish peroxidase was present in the tubules. Moreover, the surface to volume ratio remained constant with increasing time of cytochalasin D incubation. Accordingly, the surface-connected tubules were not derived from endocytic structures but were formed by invagination of the plasma membrane. The tubule formation is reversible. When microtubules are depolymerized by nocodazole or colchicine treatment before the cells are exposed to cytochalasine D, tubule formation is strongly inhibited. Hence, the cytochalasin D-induced plasma membrane tubulation depends on intact microtubules.

Actins↗
PubMed1996

A new drug delivery system using plasma-irradiated pharmaceutical aids. VII. Control release of theophylline from plasma-irradiated polymer-coated granules.

With a view to expanding the application of a drug delivery system (DDS) preparation using plasma-irradiated pharmaceutical aids for various dosage forms, we studied the theophylline release property from plasma-irradiate polymer-coated granules, the polymers of which differ in the plasma irradiation effect. We used a new type of rotational plasma-irradiation reactor to perform plasma-irradiation uniformly on the surface of polymer-coated granules based on scanning electron microscope (SEM) observation. It was shown that an increase in theophylline release rate with an increase in plasma duration was observed in all polymer-coated granules, although the factors of such release properties vary with the polymers, as evidenced by the SEM observations. Such results provided the criteria for selecting polymer structures for granule coating. Thus, the present method for the control of drug release is considered principally applicable not only to polymer-coated granules but also to various drug forms under consideration of the above criteria.

Delayed-Action Preparations↗
PubMed2005

Clinical characteristics of heart disease patients with a good prognosis in spite of markedly increased plasma levels of type-B natriuretic peptide (BNP): anomalous behavior of plasma BNP in hypertrophic cardiomyopathy.

BACKGROUND: Although it is not rare to encounter patients with plasma B-type natriuretic peptide (BNP) levels unequivalent to the severity of heart failure (HF), there has been little investigation to clarify the causative background of this phenomenon. METHODS AND RESULTS: Among the 1,838 outpatients whose plasma BNP was measured, persistently increased levels of BNP above 500 pg/ml was observed for more than 6 months in 14 subjects with few HF symptoms. Among these, all of 4 patients without any following cardiac events (E-/high) for 12 months showed hypertrophic nonobstructive cardiomyopathy (HNCM). When we compared the clinical parameters of these patients with those of 22 HNCM patients without any following cardiac events whose plasma BNP levels were less than 200 pg/ml, there were only 2 clinical characteristics to be distinguished: (i) plasma renin activity (PRA) and norepinephrine (NE) levels were low in spite of markedly increased levels of plasma BNP in E-/high HNCM; and (ii) echocardiographic investigation revealed that only global left atrial fractional shortening was significantly lower in E-/high HNCM. CONCLUSIONS: Plasma BNP levels do not always reflect the severity of HF in HNCM. It might be considered to utilize other clinical parameters such as NE and PRA to recognize HF severity in such patients.

Aged↗
PubMed2003

Chronic daily ethanol and withdrawal: 4. Long-term changes in plasma testosterone regulation, but no effect on GnRH gene expression or plasma LH concentrations.

Although ethanol has been repeatedly demonstrated to inhibit the hypothalamo-pituitary-testes axis by multiple mechanisms, plasma testosterone levels can be normal in alcoholics who do not exhibit severely compromised liver function and even increased in some abstinent alcoholics, suggesting that adaptive changes to chronic alcohol abuse may alter these regulatory mechanisms. To address this variability, we have investigated the effects of chronic ethanol and withdrawal on rat testosterone regulation using a well-characterized liquid diet model that we have previously demonstrated to (1) provide daily oral ethanol consumption that produces behaviorally relevant plasma ethanol levels during the active (awake) stage of the photoperiod; (2) establish physical dependence on ethanol; and (3) produce not only hypothalamo-pituitary-adrenal axis, but also behavioral (anxiety-like behavior, response to novelty, sucrose preference) changes consistent with those of actively drinking and subsequently abstinent alcoholics. The results demonstrate that chronic daily episodes of ethanol consumption and withdrawal by male Sprague-Dawley rats decreased (p < 0.01) plasma testosterone levels late in the afternoon (by 70% relative to ad libitum-fed controls and 63% relative to pair-fed controls), but not in the morning. During gradual cessation of daily ethanol consumption, morning plasma testosterone levels increased, and this 90-115% (p < 0.05) increase was maintained for 3 d after complete cessation of ethanol consumption. Three weeks after cessation of ethanol consumption, plasma testosterone levels were again increased by approx 100% (p < 0.01). Plasma luteinizing hormone (LH) concentrations and anterior hypothalamus/preoptic area gonadotropin-releasing hormone (GnRH) mRNA levels were not altered at any of these time points. Thus, chronic daily ethanol consumption and daily withdrawal induced changes in circulating testosterone regulation that (a) were time of day dependent and (b) included adaptive changes persisting long after consumption of ethanol ceased. Accordingly, resolution of changes in testosterone regulation and their potential roles in alcohol abuse and relapse will require evaluating changes throughout the circadian cycle during, shortly after, and long after active alcohol abuse.

Animals↗
PubMed1978

Human plasma kallikrein: purification, enzyme characterization and quantitative determination in plasma.

Human plasma kallikrein was isolated from a plasma fraction related to Cohn fraction IV4 by affinity- and Sephadex G-150 chromotography yielding a material with 17.3 TAME-U/A280 unit. The preparation was characterized by immunological and enzymatic methods. Complex formation with alpha2-macroglobulin, C1-inactivator and aprotinin was demonstrated by immunoelectrophoresis. The bradykinin release from high-molecular weight kininogen and its inhibition by antibodies to kallikrein, AT III and AT III-heparin complex were measured using a biological test system (rat uterus). Time dependent inactivation of kallikrein by AT III, and AT III-heparin complex was shown by means of a synthetic kallikrein substrate: Bz-Pro-Phe-Arg-pNan. The same substrate was used to measure the activation of prekallikrein in plasma by kaolin and F XII a. Antibodies raised against kallikrein were shown to inhibit the reaction specifically. A quantitative determination of plasma prekallikrein by electroimmunodiffusion according to Laurell was developed: the plasma concentration in normal individuals was found to be 1.8 - 2.2 TAME-U/ml related to kallikrein activity; this corresponds approximately to 9 - 11 mg antigen/100 ml plasma.

Animals↗
PubMed1980

Radioenzymatic determination of epinephrine, norepinephrine and dopamine in 0.1 ml plasma samples: plasma catecholamine response to submaximal and near maximal exercise.

A sensitive enzymatic isotope derivative method for simultaneous determination of epinephrine, norepinephrine, and dopamine in 0.1 ml plasma samples is described. The assay consists basically of 1. conversion of epinephrine, norepinephrine, and dopamine into their respective methyl-derivates in the presence of catechol-O-methyltransferase and S-adenosylmethionine-[3H]methyl, 2. extraction of the methylated 3H labelled amines with diethyl ether, 3. separation by thin-layer chromatography, 4. measurement in a beta radiation scintillation counter. The effect of standing upright and of submaximal and near-maximal steady state exercise on plasma epinephrine, norepinephrine, dopamine and plasma renin was studied in 16 young adults aged 22 to 34 years and 9 physically well trained boys 16-17 years old. Standing upright for 2 min did not results in significant changes in either epinephrine, norepinephrine, dopamine or plasma renin activity compared with supine (basal) values. During exercise, epinephrine, norepinephrine, dopamine and plasma renin activity increased exponentially with the work load, peak values being attained at the highest load or immediately after cessation of exercise. The respective maximal values for plasma renin activity and epinephrine and norepinephrine levels were approximately 3, 6 and 10 fold higher than basal values in the adults, and rose as high as 4, 10 and 20 fold in the boys. Peak dopamine values were only 2-3 times higher than the basal values in both adults and boys. It is concluded that the method described provides a suitable tool for a quantitative assessment of adreno-sympathetic tone during physiological and pathophysiological conditions.

Adolescent↗
PubMed1978

The effect of urinary glucose excretion on the plasma glucose clearances and plasma insulin responses to intravenous glucose loads in unanaesthesized dogs.

The effect of urinary glucose excretion on the plasma glucose clearance and insulin response to varying sizes of glucose loads was studied in normal unanaesthesized dogs. Glucose loads ranging from 0.15 to 1.25 g/kg b.w. were infused intravenously in a standard time period of 30 seconds. Plasma glucose and plasma immunoreactive insulin (IRI) concentrations were determined during one-hour after infusion. All urine excreted during the one-hour was collected by a catheterization and bladder wash-out procedure. The urinary glucose excretion was expressed as the percent of the glucose load. The urinary glucose excretion varied directly with the size of the glucose load and ranged from minimal to 12%. This would indicate that urinary losses play a considerable role proportionate to the degree of hyperglycaemia above the renal threshold. Thus, urinary loss of glucose must be recognized as an important factor infuencing the plasma glucose clearance and hence the plasma IRI response. A glucose load of 0.5 g/kg b.w. given in 30 seconds with the k-value calculated between 15-45 min would minimize the influence of urinary loss and provide more accurate plasma clearance values.

Animals↗
PubMed1982

Relationships between fat and plasma androstenone and plasma testosterone in fatty and lean young boars following castration.

The effect of weight of fatty tissue on fat and plasma androstenone and on plasma testosterone relationships was studied in the young boar following castration. For this purpose, 9 boars were castrated at 175 days of age, plasma steroid levels were determined daily up to 10 days after orchidectomy and fat androstenone concentration was measured 1, 3, 6, 10 and 15 days after castration. The results show that the apparent half-life of stored androstenone is very variable between boars (range: 4 to 14 days) and do not depend on the weight of fatty tissue. The rate of elimination of plasma androstenone is also very variable between boars. The rate of disappearance of fat androstenone following castration does not depend on the rate of androstenone release from fatty tissue to peripheral plasma but is more likely dependent on the intensity of plasma androstenone catabolism and elimination. Therefore, fat androstenone concentration in the intact boar is almost only depending on the equilibrium between the respective rates of testicular production and elimination.

Adipose Tissue↗
PubMed2003

Acute plasma glucose increase, but not early insulin response, regulates plasma ghrelin.

OBJECTIVE: The independent role of glucose and insulin in ghrelin regulation is still controversial; this is also because in healthy subjects it is difficult to isolate the increase of glucose from that of insulin. The aim of this study was to discriminate the effect of glucose increase alone and early insulin response on plasma ghrelin, comparing ghrelin variation after i.v. glucose between healthy subjects and type 2 diabetic (T2DM) subjects, in whom the early insulin response to i.v. glucose is abolished. METHODS: Plasma glucose, insulin and ghrelin levels were measured 0, 3, 5, 10, 30, 45 and 60 min after a 5 g glucose i.v. bolus in seven healthy control subjects and eight T2DM subjects. RESULTS: There were no significant differences in body mass index, basal insulin and basal ghrelin between T2DM and healthy subjects. Basal glucose levels were higher in T2DM subjects than in controls. After i.v. glucose administration, plasma glucose increased significantly in both groups and the glucose peak was higher in T2DM subjects than in controls (9.67+/-1.25 (s.d.) vs 6.88+/-1.00 mmol/l, P<0.01). Insulin increased rapidly in controls, while in T2DM subjects, plasma insulin did not rise in the first 10 min. After the glucose bolus, plasma ghrelin showed a significant reduction both in controls and in T2DM subjects after 5 min. CONCLUSION: These findings indicate that a low-dose i.v. glucose bolus reduces ghrelin both in controls and in T2DM subjects and therefore that early insulin response does not affect plasma ghrelin.

Adult↗
PubMed2004

Plasma adiponectin and serum advanced glycated end-products increase and plasma lipid concentrations decrease with increasing duration of type 2 diabetes.

OBJECTIVE: To prospectively follow the concentrations of plasma adiponectin (p-adiponectin) and serum advanced glycation end-products (s-AGE) in relation to plasma lipids and retinopathy over 3 years in type 2 diabetic patients. DESIGN AND METHODS: P-adiponectin, s-AGE, plasma lipids and diabetic retinopathy were prospectively evaluated in 61 type 2 diabetic patients at baseline and at follow up 3 years later. RESULTS: Mean p-adiponectin (from 8.84+/-5.14 to 11.05+/-6.16 microg/ml; P=0.006) and s-AGE (from 637+/-242 to 781+/-173 ng/ml; P<0.0001) concentrations had increased at follow up. In addition, HbA1c (7.7+/-1.7 to 7.4+/-1.4%; P=0.0045) and fasting C-peptide (1.00+/-0.38 to 0.81+/-0.35 nM; P=0.019) had decreased and all lipid variables had significantly improved at follow up. P-adiponectin correlated inversely with fasting C-peptide (r(s)=-0.273; P=0.045) and low-density lipoprotein (LDL)/high-density lipoprotein (HDL) ratio (r(s)=-0.362; P=0.011), and directly with plasma HDL cholesterol (r(s)=0.381; P=0.005) at follow up. Analysis of variance with adiponectin and s-AGE as dependent variables and fasting C-peptide, plasma HDL and plasma LDL cholesterol as covariates demonstrated that the increase in s-AGE was independent (P=0.001) and the increase in p-adiponectin dependent on covariate changes (P=0.862). There was a slight correlation between s-AGE at baseline versus the degree of retinopathy at follow up (r(s)=0.281; P=0.0499). CONCLUSION: Both p-adiponectin and s-AGE increased during the 3 years. The increase in p-adiponectin was explained by improvements in insulin sensitivity and dyslipidaemia, whereas the increase in s-AGE was independent of changes in metabolic covariates. s-AGE increase when the duration of type 2 diabetes increases.

Adiponectin↗
PubMed1976

Concentrations of fat and plasma 5alpha-androstenone and plasma testosterone in boars selected for rate of body weight gain and thickness of back fat during growth, sexual maturation and after mating.

The levels of 5alpha-androstenone and testosterone in peripheral plasma and 5alpha-androstenone in fat collected from 18 boars selected according to thickness of back fat and rate of gain were evaluated. Sampling was started when the animals were about 100 days of age and samples were collected every 14 days until the boars were about 240 days old. The steroid profiles varied considerably between boars, although an increase in steroid levels was found in most animals with the onset of adolescence. The regression line for the level of 5alpha-androstenone in fat and the age of the animals in days was found to be y = 0.02x-1-31. High coefficients of correlation were found between the concentration of 5alpha-androstenone in peripheral plasma and fat (r = 0-78) and between levels of 5alpha-androstenone and testosterone in peripheral plasma (r = 0-64). Levels of 5alpha-androstenone in peripheral plasma above about 15 ng/ml were usually accompanied by a heavy accumulation of 5alpha-androstenone in adipose tissue. The use of four of the boars for mating resulted in increased steroid levels in peripheral plasma and fat. Significantly higher levels of 5alpha-androstenone and testosterone were found in the peripheral plasma of boars selected for fatness and a low rate of gain than in boars selected for low back-fat thickness and a high rate of gain.

Adipose Tissue↗
PubMed1986

Suppression of ovine plasma FSH by bovine follicular fluid: neutralization by plasma from ewes immunized against an inhibin-enriched preparation from bovine follicular fluid.

Adult Merino ewes were immunized against an inhibin-enriched preparation (bFFI) obtained by affinity chromatography of bovine follicular fluid (bFF). Plasma was obtained in early luteal phase from these ewes and from control ewes immunized against bovine serum albumin. Ten months after ovariectomy the plasma concentration of FSH, but not LH, in control ewes was decreased by four s.c. injections of 8 ml bFFI (17,500 units inhibin/injection). There was no decrease in plasma concentrations of FSH or LH in immunized ewes with the same dose of bFFI. In a second study with long-term ovariectomized ewes, four injections of 20 ml plasma from the immunized ewes significantly reduced the decrease in FSH concentration caused by four injections of steroid-free bFF (2500 units inhibin/injection) in comparison with similar ewes injected with plasma from control ewes. These results show that the plasma of ewes immunized against bFFI contains substances, presumably antibodies, which neutralize the FSH-suppressive effects of bFF and bFFI in ovariectomized ewes.

Animals↗
PubMed1988

The transport of plasma thyroxine in white storks (Ciconia ciconia) and the association of high levels of plasma transthyretin (thyroxine-binding prealbumin) with moult.

Antisera raised against domestic fowl transthyretin (thyroxine-binding prealbumin) and quail albumin were used to identify thyroxine-binding proteins in the plasma of White storks (Ciconia ciconia) and to measure seasonal changes in these proteins. Three plasma proteins were shown to bind thyroxine (T4). They were albumin, transthyretin and a protein with an electrophoretic mobility on non-denaturing polyacrylamide gel electrophoresis intermediate between albumin and transthyretin. There was no thyroxine-binding globulin. The plasma concentrations of transthyretin and albumin were measured in male and female storks exposed to the photoperiodic and climatic conditions experienced during an annual cycle at 46 degrees N, 11 degrees E. The storks were in four age groups, fledglings and 1-, 2- and 3-year-old birds. A strong correlation (P less than 0.001) was found between daylength and the concentration of transthyretin during the period from February to August in the 1-, 2- and 3-year-old male and female storks, with peak values of 150-210 mg/l in May, June and July coinciding with the annual moult. Between September and January the concentration of plasma transthyretin was low, ranging between 80 and 100 mg/l. The concentration of plasma albumin was not correlated with seasonal changes in daylength and did not change during moult. It is suggested that seasonally high concentrations of plasma transthyretin may have a physiological role in moult.

Animals↗