Effect of hypophysectomy by partial decapitation and treatment with thiourea on iodine metabolism in the developing chick embryo

1983 ◽  
Vol 98 (1) ◽  
pp. 113-119 ◽  
Author(s):  
Nicole Daugèras-Bernard ◽  
François Lachiver
Keyword(s):  
Thyroid Gland ◽  
Chick Embryo ◽  
Pituitary Gland ◽  
Direct Action ◽  
Thyroid Stimulating Hormone ◽  
Yolk Sac ◽  
Pituitary Hormone ◽  
Iodine Metabolism ◽  
Tsh Secretion ◽  
And Control

The hypothesis of an action of the pituitary gland of the developing chick embryo in the transfer of iodide from the yolk of the egg to the circulation of the embryo, through the yolk sac, was tested. Plasma iodide levels and thyroidal iodine contents were determined in hypophysectomized (by partial decapitation), thiourea-injected and control embryos. From day 11 of incubation these parameters were always lower in the 'hypophysectomized' embryos than in controls, and plasma iodide levels of the thiourea-treated embryos were higher than those of controls. These results indicate a reduced iodide transfer from the yolk to the 'hypophysectomized' embryo, and an increased iodide transfer to the thioureatreated embryo. This occurred in spite of a reduced thyroid hormonal secretion in both series. The pituitary gland could therefore have a direct action (not through the thyroid gland) at the yolk sac level, to augment the transfer of iodide from the yolk in intact embryos from day 11 to the end of incubation. Thyroid-stimulating hormone (TSH) could be the pituitary hormone acting at the yolk sac level, the increased iodide transfer observed in the thiourea-injected embryos being due to a raised TSH secretion responding to the decreased plasma thyroxine levels.

The effects of insulin on TSH secretion and the morphology and physiology of the thyroid in the lizard Podarcis s. sicula

1996 ◽  
Vol 17 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Anna Capaldo ◽  
Vincenza Laforgia ◽  
Rosaria Sciarrillo ◽  
Antimo Cavagnuolo
Keyword(s):  
Thyroid Gland ◽  
Thyroid Hormones ◽  
Plasma Concentrations ◽  
Thyroid Stimulating Hormone ◽  
Lizard Species ◽  
Podarcis Sicula ◽  
Tsh Secretion ◽  
Stimulating Hormone

AbstractInsulin was administered to Podarcis sicula in winter, when the thyroid gland is inhibited. The activity of the thyroid increased, plasma concentrations of thyroid hormones and hepatic 5'-monodeiodinase activity (MDA) increased, and thyroid stimulating hormone (TSH) concentrations fell to undetectable values. This result confirms the influence of insulin on the activity of the thyroid gland in the lizard species studied. The mechanisms are still unclear, although there is evidence which leads us to believe that insulin is directly responsible for thyroid activation.

EFFECTS OF AMIODARONE ON THYROID IODINE METABOLISM IN VITRO1)

1977 ◽  
Vol 85 (4) ◽  
pp. 781-790 ◽  
Author(s):  
Bernardo E. Gluzman ◽  
Aldo H. Coleoni ◽  
Héctor M. Targovnik ◽  
Hugo Niepomniszcze
Keyword(s):  
Thyroid Gland ◽  
Direct Action ◽  
The Other ◽  
Human Thyroid ◽  
Thyroid Peroxidase ◽  
Iodide Transport ◽  
Iodine Metabolism ◽  
Per Se ◽  
Rule Out

ABSTRACT Since alterations of thyroid function have been reported in patients treated with amiodarone, 2-butyl,3-(4-diethylaminoethoxy-3,5- diiodo, benzoyl) benzofuran, the effects of this drug on the active iodide transport, organic iodine formation, thyroid peroxidase and the enzymatic iodotyrosine deiodination, were studied. In pig thyroid slices the iodide transport was affected by amiodarone at concentrations of 10−4 m and 10−5 M, showing a decrease of T/M (tissue/medium) ratios of 20% and 23%, respectively. Lower concentrations produced no significant differences from the controls. Iodotyrosine synthesis was only, but poorly, affected by 10−4 m and 10−5 m amiodarone. Inhibition of the DIT formation was greater than that produced for MIT. Thyroid peroxidase activity, as measured by the tyrosine-iodinase assay, showed a 20% decrease at 10−3 m amiodarone. None of the other concentrations have affected the activity of the enzyme, except for 7% at a concentration of 10−4 m. The iodotyrosine deiodination was affected by amiodarone only at a concentration of 10−3 m and 10−4 m. The inhibitions were of 22.5% and 16.8%, respectively. We have concluded that, under the conditions of our study, amiodarone per se does not affect the intrathyroidal iodine metabolism in concentrations which are usually present in the sera of patients treated with this drug. However, it is not possible to rule out an in vivo direct action, if amiodarone is substantially concentrated in the human thyroid gland.

Endocrine influences on growth and pigmentation of embryonic down feather cells

Development ◽  
1968 ◽  
Vol 20 (3) ◽  
pp. 319-327
Author(s):  
Leland G. Johnson
Keyword(s):  
Chick Embryo ◽  
Pituitary Gland ◽  
Developmental Studies ◽  
Pigment Granules ◽  
And Control ◽  
Feather Development

Rawles (1960) and Hamilton (1952) have outlined the development of the down feather. Details of the development and interaction of the epidermal constituents and melanocytes of the down feather were reported by Watterson (1942) and Goff (1949) described the development of the mesodermal portions of the feather. There have been several reports that normal down feather development is dependent upon undisturbed endocrine balance. One of the techniques for alteration of normal endocrine patterns in the chick embryo is the complete extirpation of the rudiments of the pituitary gland (Fugo, 1940) and many developmental studies have been based upon this method of ‘hypophysectomy’ by partial decapitation (see Hinni & Watterson, 1963). Several of these studies have cited gross effects of this operation on down feather development. Fugo (1940) found pronounced differences between operated and control embryos in length and general pigmentation of down feathers along with a ‘tremendous increase’ in the number of pigment granules in individual barbule cells of decapitated embryos.

SOME EFFECTS OF MAMMALIAN THYROID STIMULATING HORMONE, ELASMOBRANCH PITUITARY GLAND EXTRACTS AND TEMPERATURE ON THYROIDAL ACTIVITY IN NEWLY HATCHED DOGFISH (SCYLIORHINUS CANICULUS)

1961 ◽  
Vol 22 (4) ◽  
pp. 395-NP ◽  
Author(s):  
J. N. DENT ◽  
J. M. DODD
Keyword(s):  
Pituitary Gland ◽  
Low Dose ◽  
Thyroid Stimulating Hormone ◽  
Adult Brain ◽  
Effect Of Temperature ◽  
High Dose ◽  
Aqueous Extracts ◽  
Iodine Metabolism ◽  
Dose Levels ◽  
Stimulating Hormone

SUMMARY 1. Groups of recently hatched dogfish (Scyliorhinus caniculus) were given a series of injections of mammalian thyroid stimulating hormone (TSH) at three dose levels, or of aqueous extracts of each of the three lobes of the adult elasmobranch pituitary gland. Control animals received injections of distilled water or extract of adult brain. The uptake of 131I by the thyroid was measured subsequent to the injections and the histology of the thyroid was studied. The experiments were conducted over a range of temperatures, thus producing data on the effect of temperature variation on thyroidal activity. 2. The uptake of 131I by the thyroid gland is very markedly enhanced by a high dose of mammalian TSH (1·00 i.u.) and is significantly increased by an intermediate dose (0·10 i.u. TSH). Enhancement by a very low dose (0·01 i.u. TSH) is doubtful, the observed increase in uptake of 131I being significant only at the 10% level. The highest dose also accelerated folliculogenesis and induced hyperplastic changes in the thyroid. 3. There were indications that the extract of the ventral lobe of the adult elasmobranch pituitary contains a thyroid-stimulating principle. 4. The rate of iodine metabolism increases directly with the temperature over the range 8·6–13·6° C.

Hyperprolactinemia and hypothyroidism following cytotoxic therapy for central nervous system malignancies.

1987 ◽  
Vol 5 (11) ◽  
pp. 1841-1851 ◽  
Author(s):  
L S Constine ◽  
P Rubin ◽  
P D Woolf ◽  
K Doane ◽  
C M Lush
Keyword(s):  
Thyroid Gland ◽  
Hormone Secretion ◽  
Thyroid Stimulating Hormone ◽  
Gonadal Hormone ◽  
Cancer Center ◽  
Pituitary Hormone ◽  
Adult Males ◽  
Spinal Axis ◽  
Hypothalamic Pituitary Axis ◽  
Males And Females

Endocrinologic dysfunction including hyperprolactinemia and hypothyroidism are recognized complications of irradiation to the hypothalamic-pituitary axis or thyroid gland in the course of treating CNS malignancies. However, the frequency of these adverse effects in both short- and long-term survivors may be underestimated. Sixty-five patients treated in the University of Rochester Cancer Center since 1968 with radiation with or without BCNU chemotherapy for CNS tumors not involving the hypothalamic-pituitary axis were evaluated for thyroid, prolactin, and gonadal disturbances regardless of clinical symptomatology. Prolactin values were elevated in 19 of 47 patients (40%). For males and females treated with greater than 55 Gy, abnormal values were present in nine of 11 (82%) and seven of 14 (50%), respectively. For males and females treated with less than or equal to 55 Gy, two of nine (22%) and one of 13 (8%), respectively, were abnormal (P = .0001). Six of six patients who also received BCNU chemotherapy were hyperprolactinemic, as compared with six of ten (60%) who did not receive BCNU. Seven of eight females with elevated prolactin levels had menstruation abnormalities, and five of seven adult males noted a decrease in libido. Mild abnormalities in testosterone concentration were found in three of nine men evaluated, all of whom had normal gonadotropins. Of 47 patients who did not receive irradiation to the spinal axis (and thus the thyroid gland), ten (21%) had a decreased thyroxin (T4) value. Only one of these patients had an elevated thyroid-stimulating hormone (TSH) value. Of 32 patients who received greater than 55 Gy, ten (31%) had a low T4, compared with zero of 15 who received less than or equal to 55 Gy (P = .0001). Four of eight patients (50%) who also received BCNU had low T4 values, as compared with three of 14 (21%) who did not receive BCNU. Of 15 patients who were treated with 4 to 10 MV photon irradiation to the spinal axis, five patients (33%) had elevated TSH values. The mean spinal axis dose in these patients was 33 Gy. Two euthyroid children in this group manifested the early onset of puberty. The complex of endocrinologic abnormalities observed in several patients receiving only cranial irradiation, that is elevated prolactin, decreased thyroid, and gonadal hormone secretion in the presence of otherwise normal pituitary hormone levels, suggests a radiation-induced insult to the hypothalamic regulation of pituitary function.

scholarly journals DIAGNOSIS OF ENDOCRINE DISEASE: Congenital hypothyroidism: update and perspectives

2018 ◽  
Vol 179 (6) ◽  
pp. R297-R317 ◽  
Author(s):  
C Peters ◽  
A S P van Trotsenburg ◽  
N Schoenmakers
Keyword(s):  
Thyroid Gland ◽  
Congenital Hypothyroidism ◽  
Epidemiological Data ◽  
Developed Countries ◽  
Thyroid Stimulating Hormone ◽  
Pituitary Hormone ◽  
Hormone Production ◽  
Neonatal Hypothyroidism ◽  
Developmental Abnormalities ◽  
Delayed Treatment

Congenital hypothyroidism (CH) may be primary, due to a defect affecting the thyroid gland itself, or central, due to impaired thyroid-stimulating hormone (TSH)-mediated stimulation of the thyroid gland as a result of hypothalamic or pituitary pathology. Primary CH is the most common neonatal endocrine disorder, traditionally subdivided into thyroid dysgenesis (TD), referring to a spectrum of thyroid developmental abnormalities, and dyshormonogenesis, where a defective molecular pathway for thyroid hormonogenesis results in failure of hormone production by a structurally intact gland. Delayed treatment of neonatal hypothyroidism may result in profound neurodevelopmental delay; therefore, CH is screened for in developed countries to facilitate prompt diagnosis. Central congenital hypothyroidism (CCH) is a rarer entity which may occur in isolation, or (more frequently) in association with additional pituitary hormone deficits. CCH is most commonly defined biochemically by failure of appropriate TSH elevation despite subnormal thyroid hormone levels and will therefore evade diagnosis in primary, TSH-based CH-screening programmes. This review will discuss recent genetic aetiological advances in CH and summarize epidemiological data and clinical diagnostic challenges, focussing on primary CH and isolated CCH.

Effects of trifluoperazine on rat prolactin, growth hormone, thyroid stimulating hormone and adrenocorticotrophin secretion in vitro

1983 ◽  
Vol 103 (4) ◽  
pp. 492-496 ◽  
Author(s):  
Ruth C. Powell ◽  
Mark Daniels ◽  
Graham K. Innes ◽  
Michael J. Ashby ◽  
Keith Mashiter
Keyword(s):  
Growth Hormone ◽  
Primary Cultures ◽  
Hormone Secretion ◽  
Thyroid Stimulating Hormone ◽  
Pituitary Hormone ◽  
Gh Secretion ◽  
Tsh Secretion ◽  
Stimulation Of ◽  
Stimulating Hormone

Abstract. We have studied the effects of trifluoperazine, a proposed inhibitor of calmodulin directed cellular function, on adrenocorticotrophic hormone (ACTH), thyroid stimulating hormone (TSH), prolactin (Prl) and growth hormone (GH) secretion from primary cultures of rat adenohypophyseal cells. 5 × 10−6 m and 10−5 m trifluoperazine caused a significant (P < 0.005) reversible dose-related decrease in basal Prl secretion but was less effective on basal GH secretion, significant reversible inhibition (P< 0.005) occurring only with 10−5 m. Trifluoperazine did not consistently alter basal ACTH or TSH secretion but did inhibit 10−2 m theophylline stimulation of ACTH, Prl and GH secretion and 1.5 × 10−7 m TRH stimulation of TSH and Prl secretion. Paradoxically 10−5 m trifluoperazine enhanced theophylline stimulation of TSH secretion. Our results show trifluoperazine to have differential effects on Prl, GH, ACTH and TSH secretion, which are consistent with the known calcium dependence of pituitary hormone secretion and may suggest a role for calmodulin in this process.

scholarly journals Effects of 6-Methoxy-l,2,3,4-tetrahydro-b-carboline and Yohimbine on Hypothalamic Monoamine Status and Pituitary Hormone Release in the Rat

1983 ◽  
Vol 36 (4) ◽  
pp. 379 ◽  
Author(s):  
GA Smythe ◽  
M W Duncan ◽  
JE Bradshaw ◽  
MV Nicholson
Keyword(s):  
Growth Hormone ◽  
Neuronal Activity ◽  
Specific Effect ◽  
Thyroid Stimulating Hormone ◽  
Pituitary Hormone ◽  
Hormone Release ◽  
Tsh Secretion ◽  
Pituitary Prolactin ◽  
Hypothalamic Dopamine ◽  
Acth Release

Shortly after administration of 6-methoxy-1,2,3,4-tetrahydro-ft-carboline (6-MeOTHBC) and yohimbine to normal or hypothyroid rats [the latter exhibiting chronically elevated levels of serotonin (5-HT) neuronal activity in the hypothalamus] there was a highly significant increase in hypothalamic noradrenaline (NA) activity and in ACTH release concomittant with a reduction in hypothalamic 5-HT activity (P< 0'01) and in growth hormone (GH) (P<O'01) and in thyroid stimulating hormone (TSH) (P< 0'01) release from the pituitary. Both compounds caused an increase in hypothalamic dopamine (DA) metabolism and in pituitary prolactin (PRL) release in normal rats (P<0'01) but only yohimbine exerted this action in hypothyroid rats. Lower doses of 6-MeOTHBC exerted a relatively specific effect in hypothyroid rats, reducing (P< 0�01) 5-HT neuronal activity in parallel with pituitary TSH secretion (P<0�05). While gross effects of 6-MeOTHBC and yohimbine were similar with respect to their effects on NA and 5-HT status in the hypothalamus, there were quantitative differences. 6-MeOTHBC always caused a greater decrease in 5-HT turnover and a lesser increase in NA turnover than did yohimbine.

THE EFFECTS OF TREATMENT WITH GONADOTROPHINS OR WITH OESTROGEN ON THE THYROID GLAND OF THE IMMATURE RAT

1966 ◽  
Vol 35 (3) ◽  
pp. 263-270 ◽  
Author(s):  
K. BROWN-GRANT
Keyword(s):  
Thyroid Gland ◽  
Hormone Secretion ◽  
Thyroid Stimulating Hormone ◽  
Female Rats ◽  
Male Rats ◽  
Luteinizing Hormone Secretion ◽  
Immature Female ◽  
Immature Rat ◽  
Tsh Secretion ◽  
Pregnant Mare Serum Gonadotrophin

SUMMARY The uptake of 131I by the thyroid gland increased 72 hr. after the injection of pregnant mare serum gonadotrophin (PMS) into immature female rats whether ovulation occurred or not. PMS failed to produce this effect in male rats but oestrogen administration increased 131I uptake in both male and female immature rats, suggesting that oestrogen was responsible for the effect of PMS in females. Both PMS and oestrogen may increase the uptake of radioactive phosphate by the thyroid of female but not male rats; oestrogen may stimulate thyroid-stimulating hormone (TSH) secretion in immature female rats. These effects of oestrogen in the female made it impossible to determine whether the 'ovulatory surge' in luteinizing hormone secretion in PMS-treated rats was associated with an increased secretion of TSH or not.

The Pituitary Gland: Embryology, Physiology, and Pathophysiology

2000 ◽  
Vol 19 (2) ◽  
pp. 9-17 ◽  
Author(s):  
Angela Dorton
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Pituitary Hormones ◽  
Thyroid Stimulating Hormone ◽  
The Body ◽  
Pars Intermedia ◽  
Pituitary Hormone ◽  
Pars Tuberalis ◽  
Pars Distalis ◽  
Stimulating Hormone

The pituitary gland, the “master gland” of the body, is composed of endocrine cells, which secrete hormones essential for homeostasis. The gland consists of the adenohypophysis (anterior pituitary) and the neurohypophysis (posterior pituitary), two unique structures that differ anatomically and functionally.The neurohypophysis is innervated by nerve cells in the hypothalamus and forms the connection between it and the pituitary gland. The hypothalamus stimulates release and inhibition of pituitary hormones. The neurohypophysis secretes oxytocin and antidiuretic hormone.The adenohypophysis is composed of three structures: the pars distalis, the pars intermedia, and the pars tuberalis. The anterior pituitary (pars distalis) is responsible for the release of hormones that include growth hormone, prolactin, thyroid-stimulating hormone, follicle-stimulating hormone, luteinizing hormone, adrenocorticotropic hormone, and melanocyte-stimulating hormone.Disorders of the pituitary are predominately those of insufficient hormone release and may have profound effects on the neonate. The potential causes of and clinical symptomatology that may accompany pituitary hormone insufficiency in the neonatal period are explored.

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