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Few autoantibodies directed against thyroglobulin (TgAbs) have been fully characterized in man. The present study was designed to characterize TgAbs from patients with unusually high titers (> 1: 512) using the tanned red cell hemagglutination technique (TRC). IgG was isolated from the sera of subjects with Hashimoto’s thyroiditis (n = 4), subacute thyroiditis (n = 1) and Graves’ disease (n = 1) using DEAE-Sephacel chromatography. Isolated TgAbs were substituted as first antibody in a double antibody thyroglobulin (Tg) RIA and the Ka’s were determined by Scatchard analysis. Molecular ratios of antibody to antigen, TgAb: Tg, were calculated from quantitative precipitin curves. The clonality of each antibody was determined using agarose isoelectric focusing and131I labeled Tg as an autoradiographic probe. All six TgAbs were polyclonal. The Ka’s were on the order of 109–1010. In two sera TgAb: Tg ratios of 20: 1 and 8: 1 were obtained. These results are significant when compared to previously characterized Tg autoantibodies which have been of low titer, low Ka (105), and have been directed towards a restricted portion of the Tg molecule (TgAb: Tg ratios of 2: 1 to 6:1). In view of their high affinity constants and recognition of a less restricted portion of the Tg molecule, some of the TgAb’s with unusually high titers behave more like Tg heteroantibodies than autoantibodies.

The roles of photoperiod, energy balance, and concentrations of plasma total calcium (CaT) on daily changes in plasma calcitonin (CT) were investigated in broiler breeder hens (84–100 weeks old). In the first study, broiler breeder hens (n=24), reared on 14L:10D, were divided into two groups. One group was transferred from a restricted diet (DR) of 150 g/day toad libitum(AL) for 14 days, while the other group remained on DR. After 2 weeks ofad libitumfeeding, birds from each group (AL and DR) were bled every 2 hr for 24 hr for measurement of plasma CaTand CT. In a second study, the hens (n=20) were transferred to continuous light (LL) for 30 days. After the 30 days, food was removed from one group for 48 hr prior to blood sampling for 24 hr at 3-hr intervals. In a third study, birds were transferred to an ahemeral light cycle (11L:10D) for 28 days. Food was removed from the birds (n=11) for 48 hr prior to blood sampling every 3 hr for 24 hr. Four weeks later the same birds were bled again for 24 hr, but this time the birds were maintained on a restricted feeding schedule. Plasma CT was measured by a specific heterologous electrochemiluminescent (ECL) assay while plasma CaTwas measured by atomic absorption. The results showed that plasma CT concentrations did not correlate with plasma CaTconcentrations. Comparisons made between initial and final CaTand CT concentrations indicated an effect of stress due to repeated handling of the birds. Concentrations of plasma CT were significantly reduced in the fasted animals (P<0.05) compared to diet-restricted controls. There was a significant increase in plasma CT during the dark period of fed animals which was abolished in animals maintained on LL or fasted. In conclusion, a surge in plasma CT requires that the hens be provided food and that they be exposed to a dark cycle.

1. The effect of 100 g rapeseed meal (RSM)/kg diet on the energy metabolism of hybrid laying hens was examined by indirect calorimetry. Thyroid hormone concentrations, thyroid weight, liver weight and body weight, egg production and food intake were also measured.2. Fasting heat production was significantly lower in hens receiving RSM than in controls, but this difference disappeared when the birds were fed.3. Thyroid hormone concentrations decreased, while thyroid and liver weights increased slightly; none of these effects was significant. Body weight, egg production and food intake were unaffected and no liver haemorrhages were noted.4. The maintenance metabolisable energy (ME) requirement of control and treated birds, estimated from short-term energy balance measurements, was 474 kJ/kg0.75 d; net availability of ME in both treatments was 0.85.

The effect of 17β-estradiol (E₂) on Ca-, Mg-, and Ca-Mg-ATPase activity was investigated in the shell gland of 6-week-old chicks. In the first study, each of 42 birds was implanted with three E₂ (Compudose-200) pellets. An additional 6 sham-implanted birds served as controls for measurements of body weight and concentrations of E₂ and Ca in plasma. The activities of Mg-, Ca-, and Ca-Mg-ATPase peaked coincident with maximum plasma E₂ concentrations 8 days after implantation and then progressively declined in concert with the decline in plasma E2. By 29 days after implantation, the ATPase activities were similar to those measured in birds whose E₂ pellets had been removed for 11 days. Concentrations of plasma E₂ dropped from peak values of 1676 ± 317 at Day 8 to 611 ± 180 pg/ml at Day 29. When birds whose E₂ pellets had been removed were reimplanted with three pellets per bird, plasma E₂ again increased to 1637 ± 227 pg/ml. ATPase activity in these reimplanted birds also was greater (P &lt; 0.05) than activities measured in E₂-removed or E₂-maintained birds. In a second study the Ca-ATPase K_m and V_max were determined in E₂-implanted chicks (three pellets per bird) and compared to E₂-withdrawn chicks. Five days after reimplantation of chicks with E₂, there was a significant increase in both V_max (3.38 ± 0.21 vs 2.37 ± 0.28 µg P_i/mg protein/min; P &lt; 0.05) and K_m (0.31 ± 0.02 vs 0.25 ± 0.01 mM Ca; P &lt; .01). These data demonstrate that the Ca-, Mg-, and Ca-Mg-ATPase activities in the shell gland are sensitive to changes in plasma E₂ concentrations. Copyright 1993, 1999 Academic Press

The effects of pinealectomy on the daily rhythms of concentrations of tri-iodothyronine (T3) and thyroxine (T4) were investigated in sexually immature female chickens exposed to 21-, 24- and 27-h cycles of light and darkness, or to extended periods of light or darkness for more than 24 h. In pinealectomized and control birds, rhythms in levels of plasma T3and T4were entrained by all lighting cycles and decreased in amplitude or disappeared in continuous light or darkness. In pinealectomized and control birds held on 21-h (11 h light: 10 h darkness; 11L: 10D) and 24-h (14L: 10D) lighting cycles, the peak of the T4rhythm coincided with, or lagged, the trough in the rhythm of T3while in birds held on a 27-h (14L: 13D) lighting cycle, the peak of the T4rhythm preceded the trough in the rhythm of T3.Pinealectomy resulted in significant effects on the phases or amplitudes of rhythms of T3or T4in all lighting schedules except 4L: 20D. However, these effects were not consistent in direction between experimental groups and were, therefore, of doubtful physiological significance. Pinealectomy increased the mean level of plasma T4in birds exposed to continuous light or darkness or to 4L: 20D. A corresponding reduction in mean levels of plasma T3was seen in birds exposed to continuous light or darkness.It is concluded that under the lighting conditions investigated pinealectomy had no clear effect on the phases or amplitude of daily rhythms of levels of T4or T3. However, after the effects of the feeding pattern on thyroid hormone rhythms imposed by the lighting cycle were removed by placing birds in constant lighting conditions, pinealectomy appeared to exert an inhibitory action on thyroid function.J. Endocr.(1984) 103, 337–345

Changes in concentrations of plasma luteinising hormone (LH), follicle stimulating hormone (FSH), androgen, growth hormone (GH), prolactin (Prl), thyroxine (T4) and triiodothyronine (T3) were measured during growth and sexual maturation in broiler cockerels reared in continuous light to 7 weeks and 14 h light/d thereafter. Concentrations of LH and FSH began to increase between 13 and 15 weeks, while those of androgens increased between 16 and 17 weeks. FSH concentration increased faster than that of LH. Concentrations of GH and Prl were high at 3 weeks; that of GH decreasing progressively between 3 and 14 weeks of age and thereafter remaining low, while that of Prl was low between 5 and 9 weeks, relatively high between 10 and 13 weeks, and then temporarily decreasing before increasing progressively during sexual maturation. Concentrations of T3 and T4 were higher in juvenile than in adult birds.

The deprivation of drinking water for 30 h resulted in increased corticosterone concentrations in the plasma of 8- to 10-week-old chickens. When water-deprived birds were allowed to drink ad libitumthe corticosterone concentration declined within 45 min, to the level in hydrated controls, and remained suppressed thereafter. Similar reductions in the corticosterone concentrations were also observed in water-deprived chicks which were allowed to drink for only 5 min, 1 min or 5 s. The involvement of visual stimuli in mediating this adrenocortical response was demonstrated by a comparable decline in the corticosterone concentration in water-deprived birds which were presented with water but not allowed access to it. Non-visual stimuli also appeared to be causally involved in the adrenocortical suppression after drinking, since the intraperitoneal injection of tap water (40 ml per bird) also resulted in a lowering of the corticosterone level. However, in the absence of appropriate reinforcement from metabolic stimuli, a rebound in the corticosterone concentration was observed in birds prevented from drinking, in birds unable to satiate their thirst and in birds rehydrated (orally or intraperitoneally) without feeding.These results demonstrate adrenocortical suppression in water-deprived chickens after free access to food and water and the involvement of visual and non-visual stimuli in mediating this response. The maintenance of adrenocortical suppression is dependent upon metabolic stimuli associated with food and water intake.J. Endocr.(1985) 104, 225–231

1. The concentrations of plasma luteinising hormone (LH), thyroxine and prolactin were measured in about 200 birds from each of two homogenous strains of White Leghorn hens at 9 weeks of age and related to subsequent egg production.2. Within each strain, no relationships were found in individual birds between the concentrations of the plasma hormones and subsequent egg production after 90, 180 and 270 d of laying.3. Single measurements of plasma LH, thyroxine or prolactin before the onset of lay do not appear to be useful criteria for the selection of egg-laying strains.

The deprivation of food for 48 h markedly increased (P< 0·001) the corticosterone concentration in the plasma of 7- to 8-week-old chickens. When fasted birds were refed for 2 min or 5 s the corticosterone concentration fell to the level in fed birds within 30 min of refeeding. In fasted and refed birds the plasma corticosterone concentration remained lowered for at least 150 min after a 2-min period of refeeding, whereas in birds refed for 5 s the concentration had increased within 120 min to that in fasted birds. When fasted birds were refed 1, 5, 15 or 30 g diet the corticosterone level was again markedly reduced (P< 0·001) within 45 min of refeeding. The magnitude of this post-feeding decline was unrelated to the amount of food eaten, although its duration was; the level in birds refed 1, 5 or 15 g food increasing to that in fasted birds within 90, 135 and 225 min respectively. The corticosterone level in birds refed 30 g diet remained reduced for at least 225 min but increased to that in fasted birds 24 h after refeeding. The initial decline in the corticosterone concentration was unrelated to the consumption of food, since a similar reduction in the corticosterone level was observed in fasted birds which were given the sight of food but prevented from eating it by Perspex lids attached to the food troughs. This initial decline in the corticosterone level was not a result of stress, as it did not occur in fasted control birds. These results suggest that the adrenocortical changes in fasted and refed birds is initially mediated by a conditioned neural stimulus (reinforcement) and is maintained as a result of peripheral metabolic effects of ingested food.In fasted chickens the concentration of plasma tri-iodothyronine (T3) was greatly reduced (P<0·001) in comparison with fed birds. When fasted birds were refed for 2 min or with 5, 15 or 30 g diet, the level of plasma T3was increased (P< 0·05) 90 min after refeeding although not to the level in birds which had free access to food. The magnitude and duration of this increase was related to the amount of food consumed and was not observed in birds refed for 5 s or with 1 g food or in fasted birds given sight of but not access to food.

Immature cockerels (4- to 5-weeks old) were passively immunized, with antiserum raised in sheep, against thyrotrophin-releasing hormone (TRH). The administration of TRH antiserum (anti-TRH) at doses of 0·5, 1·0 or 2·0 ml/kg lowered, within 1 h, the basal concentration of plasma GH for at least 24 h. The administration of normal sheep serum had no significant effect on the GH concentration in control birds. Although the GH response to TRH (1·0 or 10·0 μg/kg) was not impaired in birds treated 1 h previously with anti-TRH, prior incubation (at 39 °C for 1 h) of TRH (20 μg/ml) with an equal volume of anti-TRH completely suppressed the stimulatory effect of TRH (10 pg/kg) on GH secretion in vivo. These results suggest that TRH is physiologically involved in the hypothalamic control of GH secretion in the domestic fowl.J. Endocr.(1985) 105, 351–355

Eight adult Soay rams (four control and four cranially sympathectomized by removal of the superior cervical ganglia) were exposed to alternating 16-week periods of short days of 8 h light: 16 h darkness (8L : 16D) and long days (16L : 8D) for more than 3 years, and the changes in the diameter of the testes were recorded. Once during short days and once during long days blood samples were collected hourly for 28 h, and the concentrations of melatonin, prolactin, FSH, LH, testosterone, tri-iodothyronine (T3), thyroxine (T4) and cortisol were measured by radioimmunoassay.In the control rams the testes were reduced in size during long days compared to short days, and the blood concentrations (24-h mean values) of FSH, LH and testosterone were decreased. The levels of prolactin were much increased, while there was no significant change in the mean levels of melatonin, T3, T4and cortisol. During both photoperiods there was considerable hour-to-hour variation in all eight hormones indicative of episodic secretion, as well as a consistent variation related to the time of day which was most pronounced for melatonin and T3. There was a clear difference in the daily profile of plasma melatonin levels between short and long days.In the superior cervical ganglionectomized rams there were no significant changes in the size of the testes or in the hormone titres between short and long days. Compared to the controls the plasma levels of LH, FSH, testosterone and prolactin were in the intermediate range. Some consistent diurnal variation was evident in the levels of all the hormones measured, with a pattern similar to the controls for a few of the hormones (e.g. T3) but quite different for others (e.g. melatonin).

Seasonal changes in concentrations of plasma LH, prolactin, thyroxine (T4), GH and corticosterone were measured in captive male ring doves exposed to natural lighting at latitude 56 °N. Plasma LH levels decreased steeply in autumn when the daylength fell below about 12·5 h but increased in November as the birds became short-day refractory. In comparison with plasma LH concentrations in a group of short-day refractory birds exposed to 6 h light/day from the winter solstice, plasma LH levels in birds exposed to natural lighting increased further in spring after the natural daylength reached about 12·5 h. There were no seasonal changes in plasma prolactin concentrations and plasma T4concentrations were at their highest during December, January and February, the coldest months of the year. The seasonal fall in plasma LH levels in September was associated with a transitory increase in plasma T4, a transitory decrease in plasma corticosterone and a sustained increase in plasma GH.It is suggested that in the ring dove, short-day refractoriness develops rapidly in November to allow the bird to breed when the opportunity arises, during the winter and early spring. The annual breeding cycle is synchronized by a short-day induced regression of the reproductive system in the autumn, the primary function of which may be to enable the birds to meet the energy requirements for the annual moult. The changes in plasma T4, corticosterone and especially of GH at this time of year are probably concerned with the control of moult or the associated changes in energy requirements.J. Endocr.(1986) 108,385–391

Cells binding anti-bovine TSH ß serum were found exclusively in the rostral lobe of the adenohypophysis of the drake using the peroxidase-antiperoxidase complex unlabelled antibody method. The specificity of the binding of the anti-serum to TSH cells was established by relating the morphology and relative abundance of immunochemically stained cells to the TSH content of the adenohypophysis after experimentally altering the activity of the pituitary-thyroid axis. The TSH activity of the adenohypophysis was assessed indirectly, by the weight of the thyroid glands, and directly, by bioassay. As determined by bioassay, the TSH content of the rostral lobe of the adenohypohysis was much greater than that of the caudal lobe. Compared with control drakes, immunochemically stained cells in birds fed a goitrogen, methimazole, seemed to be enlarged and were closer together, while the stained cells in drakes injected with thyroxine were shrunken and less intensely stained. The TSH content of the adenohypophysis was increased in drakes fed methimazole. Castration did not alter the TSH content of the adenohypophysis or change the morphology of immunochemically stained cells. These observations suggest that in the drake: 1) anti-bovine TSH ß serum binds specifically to TSH cells; 2) the TSH cells occur in the rostral and not in the caudal lobe of the adenohypophysis; and 3) the activity of TSH cells is not inhibited by the feedback effects of gonadal steroids.

The interaction between 17β-estradiol (E₂), vitamin D₃ (D₃), and dietary Ca on the activities of Ca-ATPase and alkaline phosphatase (AP) was determined in the intestine of young female chicks. Chicks (n = 36) were assigned to two groups, one of which was transferred to a low Ca (0.2%) diet and the other maintained on a regular diet. One week later, each group was further divided into three subgroups and given daily injections of 0(oil), 0.25, or 0.5 mg E₂/kg body wt for 14 days. E₂ treatment as well as low dietary Ca significantly increased AP activity (P &lt; 0.05), whereas the highest E₂ dose decreased jejunal Ca-ATPase (P &lt; 0.05). In a separate study, day-old chicks (n = 40) fed a purified diet supplemented with or without D₃ for 24 days were divided into two subgroups and administered daily injections of either 0 or 0.25 mg estrogen 3-benzoate/kg body wt for 5 days. E₂ alone or in combination with D₃ failed to change Ca-ATPase activity in either the duodenum or the jejunum. However, E₂ enhanced the D₃-stimulated AP activity measured in the supernatant of duodenum (D₃, P &lt; 0.001; E₂, P > 0.05; E₂ × D₃, P &lt; 0.05) and jejunum (D₃, P &lt; 0.001; E₂, P > 0.05; E₂ × D₃, P = 0.06). Daily injections of 0.5 mg E₂/kg body wt for 6 days to 6-week-old D₃-adequate chicks (n = 16) significantly increased AP activity in jejunum but not in liver and kidney (P &lt; 0.05). In conclusion, E₂ treatment enhanced the activity of intestinal AP but not Ca-ATPase. This enhancement was independent of dietary Ca, but was D₃-dependent and tissue specific. The results suggest that the pubertal increase in plasma E₂ can affect Ca absorption from the intestine by increasing the activity of AP. Copyright 1993, 1999 Academic Press

Surgical thyroidectomy increases basal and TRH-induced GH concentrations in the peripheral plasma of immature domestic fowl. Replacement therapy with thyroxine (T4; 100 μg/kg per day for 7 days, i.m.) suppressed the GH responses to thyroidectomy. Bolus administration of T4(10 μg/kg, i.m.) to thyroidectomized birds promptly lowered the circulating GH concentrations, which remained suppressed for at least 4 h. Chronic (daily injections for 7 days) or acute (one injection) pretreatment of thyroidectomized birds with iopanoic acid (IOP; 40 mg/bird, i.m.) before the bolus administration of T4attenuated, but did not prevent, inhibition of circulating GH levels by T4. Administration of IOP (40 mg/bird i.m.) 24 h and immediately before the administration of tri-iodothyronine (T3; 3 μg/kg, i.m.) or T4(10 μg/kg, i.m.) also failed to suppress thyroidal inhibition of circulating GH concentrations in thyroidectomized birds. Administration of IOP alone had no effect on GH concentrations. Circulating T3concentrations were not enhanced following the administration of T4to IOP-treated birds, indicating its inhibition of hepatic monodeiodinase activity.The metabolic clearance rate (MCR) of 125I-labelled chicken GH in the plasma of thyroidectomized fowl was less than that in sham-thyroidectomized birds. Following pretreatment with T4(100 μg/kg per day for 7 days) sham-thyroidectomized and thyroidectomized birds did not differ significantly in their MCR. The GH secretion rate in thyroidectomized birds was similar to that in sham-thyroidectomized birds and in both groups was markedly reduced following pretreatment with T4.These results demonstrate thyroidal inhibition of circulating GH concentrations in fowl. Both T3and T4inhibited GH concentrations and the effect of T4was not simply due to its role as a T3prohormone. In the absence of thyroid hormones, the MCR of GH was reduced but its secretion rate was not enhanced. A significant reduction of GH secretion rate occurs in response to exogenous T4, in the absence of any change in GH metabolism.Journal of Endocrinology(1990) 124,215–223

A thyroid tumor cell line has been established from the metastases of a follicular carcinoma in a female patient. Although the primary tumor released thyroglobulin (Tg) into the circulation (> 10000 ng/ml), the uptake of I131was less than 2%. After 37 replications the doubling time was 4 days and confluency was reached after 7 days from inoculation of 3 × 107cells. This human thyroid tumor cell line has now been growing in culture for several years. An aneuploid chromosomal pattern was observed (62–82 chromosomes). A pair of X chromosomes was present but no Y chromosome was found which is compatible with the female origin of the cell line. EM studies revealed the presence of microvilli. Immunoperoxidase staining using specific anti-human Tg antisera indicated the presence of Tg within the cells. Nude mice developed solid-cystic tumors within 6 months after injection of the cells. The basal release of immunodetectable Tg, as measured in a perifusion system, increased in response to thyroid stimulating hormone (TSH) (p< 0.025) or TSH combined with theophylline (p< 0.001). Unusual isoenzyme patterns for galactose-1-phosphate-uridyltransferase (GALT) and phosphoglucomutase1(PGM1) were detected in the tumor, compared with normal human fibroblasts and blood cells and isoenzyme patterns from the patient’s lymphocytes. Because this malignant human thyroid follicular cell line has retained the ability to synthesize Tg it represents a valuable model for the study of human follicular carcinomas.