Term
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Definition
| constitute about 20% of the pituitary cell population. |
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Term
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Definition
| precursor protein for ACTH that also generates B-lipotropin, B-endorphin, met-enkephalin, MSH, CLIP, corticotropin. gene is on chromosome 2. 3 promotor regions for pituitary and periperal tissue-specific POMC expression. |
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Term
| Hormones under control of CRH |
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Definition
| (corticotropin releasing hormone); ACTH, B-lipoprotein. |
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Term
| Dopamine controlled hormones |
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Definition
| located in intermediate lobe. a-MSH, CLIP, gama-lipotropin, b-endorphin. |
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Term
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Definition
| proopiomelanocortin derivative that has potent anti-inflammatory influences on brain. protects skin from UV. |
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Term
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Definition
| corticotropin like peptide; might be endogenous modulator of pancreatic exocrine function. |
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Term
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Definition
| may act to inhibit the release of substance P, which may account for the sedating effects of endogenous endorphins and narcotics given exogenously, such as heroin and morphin. rise in blood levels of endorphins is measureable after exercise, and sex! |
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Term
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Definition
| neurohormone which promtoes utilization of fat by body and precursor to endorphin, secretion falls with age sharply. |
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Term
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Definition
| pulsatile and exhibits a characteristic circadian rhythm, peaking at 6 a.m.; secretion mediated by CRH stimulating ACTH. Diurnal rhythmicity causes a pick before awakening and a decline as the day progresses. diurnal is reflection of neural control and provokes diurnal secretion of cortisol from adrenal cortex. episodic release independant of cortisol level. |
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Term
| Measurement of ACTH levels |
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Definition
| basal morning concentration is from 9-52pg/ml, short plasma half-life(7-12minutes) |
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Term
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Definition
| GPCR. major function of HPA axis is to maintain metabolic homeostasis and to mediate the neuroendocrine stress response. Peripheral and central afferent signals are integrated by pituitary corticotrope cell stimulate adrenal cortisol secretion, mineralocorticoid, androgenic steroids from cortex. |
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Term
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Definition
| stress, hypoglycemia, pain, trauma, hypoxia, cold exposure, surgery, depression stiumlate ACTH and cortisol secretion. |
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Term
| Two mechanisms of feedback for ACTH |
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Definition
| fast feedback(short), slow feedback(long) |
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Term
| Negative feedback on ACTH |
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Definition
| negative feedback of cortisol/synthetic glucocorticoids on ACTH secretion occurs at the hypothalmo/pituitary levels. (Dexamehtasone) |
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Term
| Pituitary Cushing's syndrome |
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Definition
| hypersecretion of ACTH by the pituitary tumor 60-70% |
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Term
| Adrenal Cushing's syndrome |
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Definition
| hypersecretion of ACTH by a non-pituitary, such as cancer adenoma, hyperplasia 15% |
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Term
| Ectopic Cushing's syndrome |
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Definition
| small cell carcinoma of lung 15% |
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Term
| Secondary Adrenal Insufficiency |
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Definition
| occurs as a result of pituitary ACTH deficiency. |
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Term
| Etiology of ACTH deficiency |
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Definition
| due to suppresion of HPA axis. surgical resection of an ACTH-secreting pituitary adenoma that has suppressed the HPA axis. sellar lesions may lead to ACTH deficiency |
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Term
| Clinical signs and symptoms of ACTH deficiency |
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Definition
| Fatigue, weakness, anorexia, nausea, vomiting, hypoglycemia |
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Term
| Treatment of ACTH Deficiency |
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Definition
| glucocorticoid replacement therapy improves most features of ACTH deficiency. 5mg each morning; 2.5 mg each evening. |
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Term
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Definition
| comprise about 10% of anterior pituitary cells and produce two gonadotropins-LH & FSH |
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Term
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Definition
| 10-amino-acid peptide synthesized in preoptic region regulates synthesis and secretin of LH and FSH. acts through GPCR to stimulate phospholipase C, protein kinase C signalling pathways. |
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Term
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Definition
| regulates ovarian follicle development and stimulates ovarian estrogen production. |
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Term
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Definition
| mediates ovulation and maintenance of the corpus luteum. |
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Term
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Definition
| induces Leydig cell testoserone synthesis and secretion. |
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Term
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Definition
| stimulates seminiferous tubule development that regulates spermatogenesis |
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Term
| Etiology of Gonadotropin Deficiency |
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Definition
| Hypopituitarism, Hyperprolactinemia, Hypothalamic defects associated with GnRH deficiency, Hypogonadotropic hypogonadism (Kallmans syndrome), mutation in DAX1 gene, GnRH receptor mutations. |
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Term
| Signs and Symptoms of Gonadotropin Deficiency (premenopausal woman) |
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Definition
| diminished ovarain function leading to oligomenorrhea or amenorrhea, infertility, decreased vaginal secretions, decreased libido, breast atrophy. |
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Term
| Clinical Signs and Symptoms of Gonadotropin Deficiency (hypogonadal adult males) |
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Definition
| secondary testicular failure is associated with decreased libido and potency, infertility, decreased muscle mass with weakness, reduced beard and body hair growth, soft testes. |
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Term
| Lab investigation of gonadotropin deficiency |
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Definition
| central hypogonadism associated with low or inappropriately low serum gonadotropin levels and low sex hormone concentrates(testosterone male, estradiol female). 3 samples drawn 20 min apart for accurate measurement of LH FSH. |
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Term
| Treatment of Gonadotropin Deficiency |
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Definition
| (Male). testosterone replacement necessary to achieve normal growth and development of external genitalia, secondary sex chara. (Premenopausal woman) cyclical replacement of estrogen and progesterone maintains secondary sex characteristics and GI tract integrity and premature osteoporosis. |
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Term
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Definition
| thyrotrope cells comprise 5% of AP cell population. |
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Term
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Definition
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Term
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Definition
| hypothalamic tripeptide that acts through a G-protein coupled receptor to stimulate phospholipase C, protein kinase C. stimulates TSH synth, secret; and lactotrope cells to secrete PRL. |
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Term
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Definition
| inhibited by thyroid hormones, dopamine, and glucocorticoids. |
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Term
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Definition
| secreted in pulses, TSH does GPCR on thyroid follicular cells to stimulate thyroid hormone synthesis and release. |
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Term
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Definition
| central hypothyroidism. Pituitary hypothyroidism is characterized by low basal TSH levels. Contrasting this hypothalamic origin may have normal or elevated TSH levles. TRH injected causes 2-3fold increase in TSH and PRL in 30 min. |
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Term
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Definition
| TSH-producing macro adenomas. mutation in the thyroid hormone B receptor. |
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Term
| Treatment of TSH-secreting adenomas |
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Definition
| remove the tumor mass surgically, transsphenoidal or sub frontal. Somatostatin analogue treatement effectively normalizes TSH. |
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Term
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Definition
| small located in midline attached to posterior end of roof of third ventricle in the brain. develops during second month of gestation as a diverticulum in diencephalic roof of 3rd ventricle. |
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Term
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Definition
| 95% of cells in pineal gland; large light and round nuclei |
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Term
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Definition
| (glial cells: dark, elongated nuclei) located in pineal gland |
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Term
| Innervation of Pineal Body |
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Definition
| innervated by postganglionic sympathtetic fibers derived from the superior cervical ganglion. |
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Term
| Blood Supply of Pineal Body |
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Definition
| arterial blood supply comes from posterior choroidal artery, small artery that feeds the pineal and other nearby structures that secrete the CSF into the ventricular system./ |
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Term
| Venous Drainage of Pineal body |
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Definition
| internal cerebral veins, network of veins within the brain that drain many regions. |
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Term
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Definition
| synthesis and release of melatonin stimulated by darkness and inhibited by light. |
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Term
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Definition
| causes feeling of sleepiness. can inhibit growth of tumors in animals. Removal increases incidence of cancer. Breast cancer results in lower levels of melatonin. Protects against genetic damage. Stimulates immune system. |
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Term
| Retina effect on melatonin |
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Definition
| light exposure relayed to suprachiasmatic nucleus of hypothalamus, superior cervical ganglia, post-ganglionic neurons ascend to pineal gland. |
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Term
| Synthesis, Secretin and Receptors Melatonin |
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Definition
| precursor is serotonin, derived from tryptophan. serotonin acetylated and methylated to yield melatonin. serum levels low during daylight hours, and increase during dark. |
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