Steroid hormoneIn general, the steroid hormones act by affecting the rate of protein synthesis. In general, steroid hormones take a rather long time hours to produce an insuljn. Cortisol has primarily A. None of the above is true. Which one of the following statements BEST describes the action of the parathyroid hormone?
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In general, the steroid hormones act by affecting the rate of protein synthesis. In general, steroid hormones take a rather long time hours to produce an effect. Cortisol has primarily A. None of the above is true. Which one of the following statements BEST describes the action of the parathyroid hormone? Of the following statements concerning human hormones, which one, if any, is true? Hormones do not enter the blood but act locally on surrounding cells.
Initially, all hormones are synthesized in the cell as a prohormone. None of the above. Pregnanediol is a metabolite of A. Specificity in the action of a peptide hormone is determined at the level of A.
The insulin-receptor has in common with other growth-factor receptors such as epidermal growth factor A. Androgens can be converted to estrogens in adipose tissue. NADPH and oxygen are required. The conversion of androgens to estrogens involves the aromatization of the "A" ring and the loss of two methyl groups. Testosterone can be a precursor of estrogens.
The placenta can convert DHEA-sulfate into estrogens. In normal animals and an, the rate-limiting step in the biosynthesis of the catecholamine neurotransmitters dopamine and norepinephrine is A.
The catabolism and excretion of steroid hormones A. Which of the following occurs subsequent to administration of parathyroid hormone? The active receptor is made up of 1 alpha chain and 1 beta chain. The alpha chain spans the membrane while the beta chain binds the insulin molecule. In addition to activating the intrinsic tyrosine kinase of the receptor, insulin binding also activates a phospholipase c and induces production of the phosphatidylinositol second messengers.
A and C only. The thyroid hormone found in highest concentration in blood is A. The signaling mechanism whereby glucagon results in an increased breakdown of triacylglycerol in adipose tissue involves all of the following EXCEPT A. Which vitamin is a secosteroid and acts through a steroid receptor? Which of the following enzymes is involved in the metabolism breakdown of epinephrine? Phenylethanol amine-N-methyl transferase B. Which of the following best describes the mechanism by which steroid hormones increase the relative abundance of specific proteins?
Which one of the following statements does not describe a characteristic of hormones? It functions as an anchor for the receptor B. It contains a regulatory sequence which produces a low affinity ligand binding site. It controls negative feedback upon ligand binding.
It has some intrinsic catalytic kinase activity. A and B only. Estrogen is thought be exert its metabolic effects by which one of the following? Decreasing the production of cyclic AMP. Increasing the permeability of cell membranes to molecules such as glucose and amino acids. Reaction with a specific receptor protein which in turn affects DNA metabolism.
Alteration of the phosphorylation of histones. Specificity in the action of steroid hormones is determined at the level of A. Thyroid hormone is produced in the thyroid gland A. Which of the following hormone combinations is NOT regulated by a negative feedback loop? LH - androgen B.
TSH - thyroid hormone C. ACTH - glucocorticoid D. Biological conversion of testosterone A. Which statement BEST describes the regulatory action of steroid hormones on cellular metabolic events? All of the other s are correct. The estradiol receptor Erb can inhibit the activity of ERA. What is the mechanism of this inhibition?
Blockage of transport of ERa into the nucleus B. Dissociation of the ligand from ERa C. ERb binds the ERa ligand D. Formation of heterodimers of the two receptors E. Inhibition of synthesis of ERa.
Which of the following statements is false? Phosphorylation plays an important role in many hormonal effects. In humans, there exists known protein kinases that phosphorylate proteins on serine.
In humans, there exists known protein kinases that phosphorylate proteins on methionine. In humans, there exists known protein kinases that phosphorylate proteins on tyrosine.
Aldosterone is only produced in which portion s of the adrenal gland? Zona glomerulosa of the cortex B. The glucocorticoid hormones act A. Which one of the following is a pro-vitamin D? Which of the following enzymes catalyzes the rate controlling step in cortisol biosynthesis? The identification of zinc finger domains in the structure of a hormone receptor would predict A.
Glucagon is made by the pancreatic alpha cells and stimulates liver glycogenolysis, gluconeogenesis and ketogenesis and stimulates lipolysis in adipocytes. In the adrenal medulla, DOPA decarboxylase requires pyridoxal phosphate as a cofactor.
In the adrenal medulla, epinephrine is broken down by two enzymes, monoamine oxidase and catechol O-methyl transferase. Which of the following steroids serves as the immediate precursor for the synthesis of estradiol? The major actions of parathyroid hormone are A. A and C above E. B and C above. The insulin receptor A. Which of the following is a major mineralocorticoid in man? Thyroid hormone receptors A.
The insulin receptor is regulated by auto phosphorylation of one or more residues. Parathyroid hormone is produced by the parathyroid glands located within the thyroid gland and calcitonin is produced by the clear cells within the thyroid gland.
The main targets for Parathyroid hormone are the kidney and bone while the main target for calcitonin is the bone osteoclasts. The main actions of parathyroid hormone are to raise plasma calcium and lower plasma phosphate levels while the main action of calcitonin is to lower the plasma calcium level.
A, B and C. In eukaryotic cells, adrenal corticosteroids regulate gene expression by binding to A. Down-regulation of insulin receptors is due to A. TRH thyrotropin releasing hormone B. GnRH gonadotropin releasing hormone C. CRH corticotrophin releasing hormone. CLIP corticotropin-like intermediate lobe peptide B. Catabolism of steroids involves reduction, conjugations and a final breakdown of the steroid nucleus to acetoacetate. The main organ of steroid catabolism is the adrenal gland.
The major precursor of urinary ketosteroids is cortisol. All of the above. O-Hydroxylation of progesterone gives rise to A. Regarding the endocrine system and hormone feedback, which of the following statements is false? The feedback of thyroid hormone is an example of a short-loop feedback system.
The feedback of insulin is an example of a long-loop feedback system. For the most part, the hormones of the endocrine system utilize positive feedback.
Tight control of hormone levels and their actions is important in normal human homeostasis.