PMCOL 343- Glucocorticoids I
Study Set Exam
What does the HPA axis regulate - Answer Metabolism, immune responses, and the ANS
What are the three components of the HPA axis - Answer Hypothalamus, pituitary, and
adrenal gland
What is the HPA hormone released by the hypothalamus - Answer Corticotrophin
releasing hormone
What is the stimulus for CRH release - Answer Physical, psychological, and
environmental stressors
What type of hormone is CRH - Answer A neuropeptide hormone
What does CRH trigger the release of - Answer Adrenocorticotropic hormone
How does CRH trigger the release of ACTH - Answer Activates GPCRs in the anterior
pituitary, inducing release of ACTH
What is ACTH synthesized from - Answer Propriomelanocortin (POMC)
What cells make ACTH - Answer Corticotrophs
Describe the role AVP plays in the HPA axis - Answer AVP / vasopressin by itself does
not increase ACTH synthesis, but potentiates the effects of CRH, increasing ACTH
synthesis
The adrenal gland is separated into the adrenal medulla (inner) and adrenal cortex
(outer); list the layers of the adrenal cortex from top to bottom - Answer Top layer = zona
glomerulosa
Middle layer = zona fasciculata
Bottom layer = zona reticularis
What hormones do the respective layers of the cortex make - Answer Zona glomerulosa
= aldosterone
Zona fasciculata = cortisol
Zona reticularis = androstenedione
What is the precursor molecule for aldosterone, cortisol / corticosterone, and
androstenedione - Answer Cholesterol
, What are the three main enzymes expressed in the zona fasciculata - Answer
17-alpha-hydroxylase
21-beta-hydroxylase
11-beta-hydroxylase
What are the two main enzymes expressed in the zona glomerulosa - Answer
21-beta-hydroxylase
11-beta-hydroxylase
What is the main enzyme expressed in the zona reticularis - Answer
17-alpha-hydroxylase
What is the difference between cortisol and corticosterone - Answer Corticosterone is
the inactive form of cortisol
What zones of the adrenal cortex are sensitive to ACTH stimulation; which are not -
Answer Zona fasciculata and reticularis are sensitive
Zona glomerulosa is not
What happens to the two zonas in the absence of ACTH - Answer Cells undergo atrophy;
impaired levels of GCs and androgens
What happens to the two zonas in the presence of elevated ACTH - Answer Hypertrophy
and hyperplasia of cells; overproduction of GCs and androgens
GCs are the primary stress hormone; what is the main endogenous GC in humans -
Answer Cortisol
Describe what synthetic GCs are used for - Answer Their anti-inflammatory and
immunosuppressive properties
Range of cortisol secretion is determined by fluctuations in ACTH release; what are the
three modes of HPA regulation - Answer 1. Diurnal rhythm regulation
2. Negative feedback regulation
3. Changes in steroidogenesis in response to stress
What are ultradian rhythms - Answer Shorter cycles that occur multiple times within a
day
How long is the ultradian rhythm for the HPA axis - Answer Around 90 minutes
Describe the peaks of both cortisol and ACTH in the ultradian rhythm - Answer ACTH
peaks, resulting in a spike of cortisol, which results in suppression of ACTH release,
resulting in a decrease in cortisol release
Study Set Exam
What does the HPA axis regulate - Answer Metabolism, immune responses, and the ANS
What are the three components of the HPA axis - Answer Hypothalamus, pituitary, and
adrenal gland
What is the HPA hormone released by the hypothalamus - Answer Corticotrophin
releasing hormone
What is the stimulus for CRH release - Answer Physical, psychological, and
environmental stressors
What type of hormone is CRH - Answer A neuropeptide hormone
What does CRH trigger the release of - Answer Adrenocorticotropic hormone
How does CRH trigger the release of ACTH - Answer Activates GPCRs in the anterior
pituitary, inducing release of ACTH
What is ACTH synthesized from - Answer Propriomelanocortin (POMC)
What cells make ACTH - Answer Corticotrophs
Describe the role AVP plays in the HPA axis - Answer AVP / vasopressin by itself does
not increase ACTH synthesis, but potentiates the effects of CRH, increasing ACTH
synthesis
The adrenal gland is separated into the adrenal medulla (inner) and adrenal cortex
(outer); list the layers of the adrenal cortex from top to bottom - Answer Top layer = zona
glomerulosa
Middle layer = zona fasciculata
Bottom layer = zona reticularis
What hormones do the respective layers of the cortex make - Answer Zona glomerulosa
= aldosterone
Zona fasciculata = cortisol
Zona reticularis = androstenedione
What is the precursor molecule for aldosterone, cortisol / corticosterone, and
androstenedione - Answer Cholesterol
, What are the three main enzymes expressed in the zona fasciculata - Answer
17-alpha-hydroxylase
21-beta-hydroxylase
11-beta-hydroxylase
What are the two main enzymes expressed in the zona glomerulosa - Answer
21-beta-hydroxylase
11-beta-hydroxylase
What is the main enzyme expressed in the zona reticularis - Answer
17-alpha-hydroxylase
What is the difference between cortisol and corticosterone - Answer Corticosterone is
the inactive form of cortisol
What zones of the adrenal cortex are sensitive to ACTH stimulation; which are not -
Answer Zona fasciculata and reticularis are sensitive
Zona glomerulosa is not
What happens to the two zonas in the absence of ACTH - Answer Cells undergo atrophy;
impaired levels of GCs and androgens
What happens to the two zonas in the presence of elevated ACTH - Answer Hypertrophy
and hyperplasia of cells; overproduction of GCs and androgens
GCs are the primary stress hormone; what is the main endogenous GC in humans -
Answer Cortisol
Describe what synthetic GCs are used for - Answer Their anti-inflammatory and
immunosuppressive properties
Range of cortisol secretion is determined by fluctuations in ACTH release; what are the
three modes of HPA regulation - Answer 1. Diurnal rhythm regulation
2. Negative feedback regulation
3. Changes in steroidogenesis in response to stress
What are ultradian rhythms - Answer Shorter cycles that occur multiple times within a
day
How long is the ultradian rhythm for the HPA axis - Answer Around 90 minutes
Describe the peaks of both cortisol and ACTH in the ultradian rhythm - Answer ACTH
peaks, resulting in a spike of cortisol, which results in suppression of ACTH release,
resulting in a decrease in cortisol release
