Exam 2 Flashcards
Under high levels of ______ and low levels of ________ Krebs cycle will be inhibited
NADH; ATP
Surgical methods, specifically surgical ablation, is a technique that affects hormone levels.
Provide an example of surgical ablation and its effect on hormone levels while including the concept of compensatory hypertrophy.
How would you confirm your example of surgical ablation.
- Surgical ablation if the removal of an organ. For example, orchidectomy is the removal of the male gonads. When one testes is removed, at first, there will not be a large negative feedback on the anterior pituitary and hypothalamus. They will continue to stimulate the production of testosterone until the one testis becomes enlarged and reaches homeostasis.
- Monitor changes in testosterone level within the blood
Alloxan, also known as Streptozotocin (STZ), destroys ______ of pancreatic islets while cobalt chloride destroys _____ of pancreatic islets.
Beta
Alpha
If action of a hormone is inhibited by actinomycin D, it can be implied that this hormone works through ______ process.
a transcriptional RNA synthesis - this hormone uses genomic effects via changing gene expression to carry out its function - most likely a steroid hormone or thyroid hormone
actinomycin D inhibits RNA production
If action of a hormone is inhibited by puromycin and cycloheximide, it can be implied that this hormone works through _____ process.
a translational protein synthesis - this hormone uses genomic effects via changing protein synthesis to carry out its function - most likely a steroid hormone or thyroid hormone
puromycin and cycloheximide inhibit protein synthesis `
Some drugs interfere with cell transport mechanism, thus inhibit protein hormone secretion. For example, colchicine destroys _______ and cytochalasin B destroys ___________.
Microtubles
Microfiliments
In genetic engineering, the leptin receptors in POMC neurons can be excised using Cre-mediated tissue-specific knockout. Describe how Cre recombinase and Lox P are used to excise the leptin receptors.
Lox P sites flank the leptin receptor gene. In order to remove the leptin receptor gene only in the POMC neurons, the Cre gene will only be expressed in POMC neurons. When Cre recombinase is expressed in POMC neurons, it lines up with lox P sites and excises DNA sequence between two loxP sequences. As a result, the leptin receptors are not able to be made in POMC neurons only. Leptin receptors are normal in all other cells and tissues.
A hormone uses cAMP as a second messenger as signal transduction mechanism to induce cellular responses.
Which enzyme is activated to produce cAMP? Briefly describe how you measure activity of this enzyme?
Adenylyl cyclase. Use enzyme assay, label ATP with radioisotope tritium [3H], trace label to cAMP to quantitate conversion of ATP to cAMP. If radioisotope labeled cAMP level is high, adenylyl cyclase enzyme activity is high.
Can you measure cAMP level to indicate the activity of this enzyme? Why or why not?
No. Because cAMP level is also altered by phosphodiesterase activity, which is unrelated to cyclase activity and cAMP formation
When discussing exogenous hormone production, specifically replacement, what are things that should be taken into consideration?
Not very specific or sophisticated - not replaced to specific cells or tissues or organs because the replaced hormone would reach all cells/tissues/organs.
Effect of hormone will regulate complete suite of hormone-dependent traits in vivo
Treatment with “standard” amount of hormone could have very different effects in different individuals
Need to manipulate animals within normal physiological range not to produce pharmacological (e.g. toxic) effects
____________ is the increase in size of a cell, while _______ is the decrease in the size of a cell
Hypertrophic
Hypotrophic/ atrophic
___________ is the increase in the number of cells present in the sample, while ___________ is the decrease in the number of cells present in the sample.
Hyperplasia
Hypoplasia
Double-labeling immunohistochemistry is a type of Immunohistochemistry (IHC) in which two specific antibodies can detect and label two different receptors in one tissue.
Provide an example of a double-labeling immunohistochemistry experiment.
- describe the procedure
.
Two specific primary antibodies to detect and label estrogen receptor and progesterone receptor in one tissue.
-
Tissue to be examined is treated with a fixative, sectioned into thin slices. Primary antibody for estrogen receptor is added to the tissue; Excess primary antibody for estrogen receptor is rinsed from the tissue. Secondary antibody (for estrogen receptor’s primary antibody) conjugated to an enzyme or a fluorescent dye. Then, primary antibody for progesterone receptor is added to the tissue; Excess primary antibody for progesterone receptor is rinsed from the tissue. Secondary antibody (for progesterone receptor’s primary antibody) conjugated to another enzyme or another fluorescent dye.
____________ method labels cells expressing mRNA of nucleic acid sequence.
In Situ Hybridization (ISH)
Immunoblot/Western Blotting allows researchers to analyze the amount of ______.
protein
A sample was injected with the radioisotope tritium [3H]-labeled thymidine (autoradiographic method) into the anterior pituitary of rats that had one testicle removed. Describe what the researchers should have observed.
In rats with a testicle removed, the autoradiographic results would have shown a silver color/grains showing mitotic division in the anterior pituitary gonadotrophs, due to reduced long-loop negative feedback → increased gonadotroph activity to synthesize and secrete gonadotropins, which leads to compensatory hypertrophy of the remaining testis.
_____ measure levels of a hormone based on biological activity.
bioassay
In radioimmunoassays (RIA), which is a type of ____________ inhibition assay, the ____________ hormone (Unknown - what you will measure) competes with ____________ hormone (*Hormone) for binding to antibody. The amount of each of these hormones is ________ proportional to each other.
Competitive
Unlabeled
Radiolabeled
Inversely
Enzyme linked immunosorbent assays (ELISA) measures the amount of hormones _______ and also measures ________, not radioisotopes.
Directly
Absorbance
You will compare insulin receptor number and affinity between a healthy person and a type 2 diabetic patient.
- Which assay would you use?
- What is your possible result? Explain your results
- Use radioreceptor assays (aka radioligand binding assay)
It tests the physiological regulation of hormone receptor number or affinity. - Chronic hyperinsulinemia: Chronic hyperinsulinemia as seen in type 2 diabetes mellitus patients reduce plasma membrane insulin receptor number (due to internalization and degradation of receptors in target cells) and reduce insulin receptor binding, therefore reduce responsiveness of target tissues to insulin.
decrease number of insulin receptor – as condition 2 in (a)
reduce insulin receptor binding affinity – as condition 1 in (b)
Neurons that produce hormones are _______ cells. Whereas, hormones released by neurons are _______.
Neuroendocrine
Neurohormones
Magnocellular neurons within the hypothalamus consist of cell bodies in ________ and ________. These neurons project into the _______ pituitary to release the neurohormones, _______ and _______, into the blood.
supraoptic nucleus (SON)
paraventricular nucleus (PVH)
Posterior
Vasopressin (AVP) or Antidiuretic Hormone (ADH)
Oxytocin (OXY)
Parvicellular neurons within the hypothalamus have cell bodies located in the ________, _________, and ________ regions. These neurons release neuropeptides (releasing factors) into pituitary portal vessel to ________ pituitary.
periventricular (PeVH)
paraventricular nucleus (PVH)
arcuate nucleus (Arc)
anterior
Hypothalamic projection neurons within the hypothalamus have cell bodies located in the ________, __________, and _________ regions. These neurons terminate at synapses on other neurons.
paraventricular nucleus (PVH)
arcuate nucleus (Arc)
lateral hypothalamic area (LHA)
Innervation by __________nervous system stimulates pancreatic beta cells to _______ insulin before, during, and after a meal.
cholinergic/ parasympathetic
release
Innervation by __________nervous system to the pancreatic beta cells _______ insulin secretion as well as prevent glucose uptake by non-muscle cells.
Sympathetic
Inhibits
Provide an example of how the nervous system controls or modifies the function of endocrine glands?
- Three types of neural cells of the central nervous system regulate neurosecretion of tropic hormones or neurohormones.
a. Neural cells at PVN and SON in the hypothalamus regulate posterior pituitary hormone release.
b. tropic hormones (hormones 1 and 2 regulate endocrine gland secretion). - Sensory and autonomic nervous system of the peripheral nervous system regulate endocrine glands.
c. Adrenal gland, pancreas, pineal glands (and many others) are regulated through direct innervation (noradrenergic and cholinergic neurotransmission) from autonomic (sympathetic and parasympathetic) nervous system.
The pituitary gland gland is often referred to as the ______ ______, and it is located just below the _______. These two structures are connected by the _______ which contains nerve fibers and blood vessels (hypothalamic-pituitary portal system). Together, they make up the ________ unit.
Master gland
Hypothalamus
Infundibulum
Hypothalamic-pituitary
When describing the composition of the Hypothalamic-pituitary unit, the _______ lobe consists of Pars Distalis and Pars Tuberalis, the ______ lobe consists of the Pars Intermedia, and the _______ lobe consists of the Pars Nervosa.
Anterior
Intermediate
Posterior
The posterior pituitary is an outgrowth of the hypothalamus which is derived from the ________ ________, whereas the anterior pituitary is derived from the _________ _________.
Neural ectoderm
Oral ectoderm
Hormones released from anterior pituitary are _________ unless directed to be released by the hypothalamus via ________ ________.
Dormant
Releasing factors
What is the main function of the Hypothalamic-pituitary unit?
Secretes a number of hormones
Most of the hormones are released from the anterior pituitary
Two protein hormones (oxytocin & vasopressin) are released from posterior pituitary
What are the 6 major hormones released by the anterior pituitary?
FSH - follicle stimulating hormone
LH - Luteinizing hormone
TSH - Thyroid stimulating hormone
ACTH - Adrenal corticotrophic hormone
GH - Growth hormone
PRL - prolactin
Do hormone isoforms exists? If so, why?
Yes, this is due to differential splicing of mRNA, post-transcriptional, or post-translational modifications. Multiple hormones can be produced from one gene transcript.
