Semester 1

Which of the following is the physiological function of leptin?

Acting in the hypothalamus as a neurotransmitter that regulates water excretion by the kidneys

Acting as a hormonal signal that reports the amount of energy stored in adipose tissue to the brain

Acting as a paracrine signal between cells in the pancreatic islets to regulate insulin secretion

Acting as an autocrine signal promoting the growth of liver cells following hepatic injury

Which of the following is the physiological function of G proteins?

σ� Acting as receptor molecules for water soluble hormones on the surface of target cells

σ� Producing cyclic AMP from ATP

Serving as a molecular signal to adenylate cyclase that a hormone has bound to its receptor

Serving as the final molecule in the protein kinase cascade

Why is the insulin receptor located on the surface membrane of muscle cells?

σ� This location reduces the need for amplification of the insulin signal within the cell

σ� The half-life of insulin is too short for it to enter the cell

σ� Insulin is almost completely bound to a carrier protein in the blood plasma

Insulin is not soluble in the lipid membrane of the cell

Which of the following is the reason why neural communication between cells is much faster than endocrine communication between cells?

The diffusion distance across the synapse is short compared to the transport distance in the circulation

σ� Neurotransmitter molecules are much more potent (stronger) than the molecules that serve as hormones

σ� Neurotransmitters have longer half-lives than hormones

σ� Neurotransmitter molecules are more soluble in water than the molecules that serve as hormones

Which of the following is the reason why the response of a target cell to a steroid hormone is slower than the response to a protein hormone?

Steroid hormones are packaged in secretory vesicles within the tissue of origin

The response to a steroid hormone requires new protein synthesis within the target cell

Steroid hormones are inactivated more rapidly than protein hormones within the target cell

Steroid hormones operate through a longer second messenger cascade than protein hormones

Which of the following hormones is secreted in a circadian pattern?

σ� Gonadotropin-releasing hormone (GnRH

σ� Glucagon

σ� Luteinizing hormone

Testosterone

Which of the following statements is true for hormones that are bound to carrier proteins in the blood plasma?

Only the free (unbound) hormone is biologically active

σ� Estrogen decreases the synthesis of sex hormone binding globulin (SHBG) and thyroxine binding globulin (TBG) by the liver

σ� Only water-soluble hormones require carrier proteins for transport in blood plasma

All of the above

Which of the following is the most reliable way to prove that a gland is secreting an excessive amount (too much) of hormone?

σ� Measure the blood hormone level at the time of day when hormone secretion is expected to be at its highest

σ� Measure the level of the hormone in a random urine sample collected in the physician’s office

Measure the blood hormone level after performing a procedure or giving a drug designed to suppress hormone secretion

Measure a molecule with a short plasma half-life that is related to the hormone

The ACTH stimulation test is most useful to diagnose which of the following conditions:

σ� Pituitary ACTH-dependent cortisol hypersecretion (Cushings disease)

σ� An aldosterone-secreting adrenal adenoma

Primary adrenal insufficiency Acortisol-secreting adrenal adenoma

Which of the following is the reason why luteinizing hormone (LH) secretion by anterior pituitary cells stops when gonadotropinreleasing hormone (GnRH) is administered in a continuous pattern instead of a pulsatile pattern?

Loss of second messenger molecules linking the GnRH receptor to LH secretion

Loss of GnRH receptors from the surface membrane of anterior pituitary cells

Rapid destruction of GnRH molecules after they bind to their receptors

Inactivation of the LH gene in the nucleus of anterior pituitary cells

Which of the following responses to insulin is observed even at the lowest blood insulin concentration in non-diabetic individuals?

σ� Stimulation of muscle glucose uptake

Inhibition of hepatic gluconeogenesis

σ� Stimulation of muscle glycogen synthesis

Inhibition of lipolysis

Individuals with hyperosmolar hyperglycemic state (HHS) may have an acidosis, but it is less severe than the acidosis seen in individuals with diabetic ketoacidosis (DKA). What is the reason for this?

Ketoacidosis does not occur in patients with HHS, but circulatory failure due to extreme dehydration may lead to excessive production of lactic acid

σ� Acidic ketone bodies are excreted more rapidly by the kidneys in patients with HHS than in patients with DKA

σ� Patients with HHS come to medical attention earlier than patients with DKA

σ� Patients with HHS are usually younger than patients with DKA

Which of the following adaptations allows a person to survive a prolonged period of fasting (starvation)?

The liver develops the ability to make glucose from fatty acids

The brain develops the ability to use ketone bodies as an energy source

The rate of fatty acid release from adipose tissue decreases over time

All of the above

All except one of the following is a function of insulin in the fed state. Which one is not a function of insulin?

Inhibition of gluconeogenesis by the liver

Stimulation of glucose uptake by muscle

Stimulation of glucose uptake by the brain

Stimulation of protein synthesis by muscle

Which of the following enzymes is activated by the decrease in the insulin/glucagon ratio as an individual enters the fasted state?

Hormone sensitive lipase

Ketogenic enzymes

Gluconeogenic enzymes

All of the above

Which of the following statements about the pathogenesis and treatment of obesity is true?

Both genetic and environmental factors contribute to the development of obesity

Most obesity is due to deficient leptin secretion

σ� Reducing the consumption of sugar-sweetened beverages has no effect on the development of obesity in a population

Appetite decreases as body fat mass is lost following restriction of food intake

Which of the following is the reason why exercise is useful in the treatment of type 2 diabetes mellitus?

Exercise increases insulin secretion by activating the sympathetic nervous system

Exercise increases insulin secretion by stimulating the paracrine effect of somatostatin on the beta cells of pancreatic islets

Exercise causes muscle cells to synthesize the Glut 2 glucose transporter in addition to the Glut 4 glucose transporter

Exercise causes the Glut 4 glucose transporter to move to the surface membrane of muscle cells even in patients with severe insulin resistance

Which of the following is the best way to prove that a patient with symptoms of hypoglycemia has an insulin-secreting islet cell tumor?

Demonstrate a fasting blood glucose level less than 0.6 g/L using a glucometer that the patient takes home

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