TSH Releasing hormones

The response of prolactin (PRL) to the hypothalamic TSH-releasing hormone (TRH) and to insulin hypoglycemia is reduced in long-term Li+-treated patients, as is the response of growth hormone to insulin hypoglycemia however the concentration of growth hormone is also reported to be elevated during Li+ treatment [170]. 

DeVito WJ, Allen E, Wu CF, Alex S, Emerson CH (1989) Thyrotropin (TSH)-releasing hormone-stimulated TSH release and TSH concentration in the guinea pig pituitary, as determined by a heterologous radioimmunoassay. Endocrinology 124 1190-7... 

Release of labelled iodine may be stimulated by injection of TRH (TSH releasing hormone, protirelin). 

Dieguez C, Foord SM, Peters JR, Hall R, Scanlon MF (1984) Interactions among epinephrine, thryotropin (TSH)-releasing hormone, dopamine, and somatostatin in the control of TSH secretion in vitro. Endocrinology 774 957-961. 

Thyrotropic hormone Hormon (TSH) polypeptide, a-chain, 92 aa, P-chain, 112 aa TSH-Releasing-Hormon peptide 3 aa... 

CLP1 Glucagon-like peptide 1 (TSH)-releasing hormone... 

Figure 1 A schematic diagram of the endocrine system of fish. TRH = thyrotrophin releasing hormone GnRH = gonadotrophin releasing hormone CRH = corticotrophin releasing hormone TSH = thyroid stimulating hormone GtH = gonadotrophins I and II ...

Otfier fiormones accelerate tfie release of free fatty acids from adipose tissue and raise tfie plasma free fatty acid concentration by increasing the rate of lipolysis of the triacylglycerol stores (Figure 25—8). These include epinephrine, norepinephrine, glucagon, adrenocorticotropic hormone (ACTH), a- and P-melanocyte-stimulat-ing hormones (MSH), thyroid-stimulating hormone (TSH), growth hormone (GH), and vasopressin. Many of these activate the hormone-sensitive hpase. For an optimal effect, most of these lipolytic processes require the presence of glucocorticoids and thyroid hormones. These hormones act in a facilitatory or permissive capacity with respect to other lipolytic endocrine factors. 

Reports of the effects of Li+ upon the thyroid gland and its associated hormones are the most abundant of those concerned with the endocrine system. Li+ inhibits thyroid hormone release, leading to reduced levels of circulating hormone, in both psychiatric patients and healthy controls [178]. In consequence of this, a negative feedback mechanism increases the production of pituitary TSH. Li+ also causes an increase in hypothalamic thyroid-releasing hormone (TRH), probably by inhibiting its re-... 

Thyroid hormone production is regulated by TSH secreted by the anterior pituitary, which in turn is under negative feedback control by the circulating level of free thyroid hormone and the positive influence of hypothalamic thyrotropin-releasing hormone. Thyroid hormone production is also regulated by extrathyroidal deiodination of T4 to T3, which can be affected by nutrition, nonthyroidal hormones, drugs, and illness. 

TSH-secreting pituitary adenomas are diagnosed by demonstrating lack of TSH response to thyrotropin-releasing hormone stimulation, inappropriate TSH levels, elevated TSH a-subunit levels, and radiologic imaging. 

Anterior part produces its own hormones in response to hypothalamic releasing hormones, e.g., adrenocorticotropic hormone ACTH, luteinizing hormone LH, follicle-stimulating hormone FSH, prolactin, growth hormone, thyroid-stimulating hormone TSH Thyroid Regulation of metabolism, development, and maturation... 

Thyroliberin (thyrotropin-releasing hormone, TRH) is one of the neurohormones of the hypothalamus (see p. 330). It stimulates pituitary gland cells to secrete thyrotropin (TSH). TRH consists of three amino acids, which are modified in characteristic ways (see p. 353). 

The secretion of anterior pituitary hormones is controlled in part by hypothalamic regulatory factors that are stored in the hypothalamus and are released into the adenohypophyseal portal vasculature. Hypothalamic regulatory factors so far identified are peptides with the exception of dopamine. Secretion of anterior pituitary hormones is also controlled by factors produced more distally that circulate in the blood. Predominant control of hormone production may be relatively simple, as with thyroid-stimulating hormone (TSH), the production of which is primarily stimulated by thyrotropin-releasing hormone (TRH) and inhibited by thyroid hormones, or it may be complex, as with prolactin, the production of which is affected by many neurotransmitters and hormones. 

Secondary hypothyroidism, or pituitary hypothyroidism, is the consequence of impaired thyroid-stimulating hormone (TSH) secretion and is less common than primary hypothyroidism. It may result from any of the causes of hypopituitarism (e.g., pituitary tumor, postpartum pituitary necrosis, trauma). Patients with secondary hypothyroidism exhibit undetectable or inappropriately low serum TSH concentrations. In secondary hypothyroidism, a normal thyroid gland lacks the normal level of TSH stimulation necessary to synthesize and secrete thyroid hormones. Such patients usually also have impaired secretion of TSH in response to exogenous thyrotropin-releasing hormone (TRH) administration. 

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