Monash University Endocrinology Assignment: GnRH and Receptor Analysis

This assignment addresses two short-answer questions related to the field of endocrinology. The first question explores the coordinated pulses of GnRH secretion despite the scattered distribution of GnRH neurons in the hypothalamus, detailing the mechanisms by which this is achieved, including the role of receptors. The second question delves into the unique characteristics of GnRH receptors, describing why they are considered 'weird' due to the absence of a cytoplasmic carboxyl-terminal tail and their functional implications, such as the ability to bind the hormone in the hypothalamus. The answers provided are concise and focus on the core concepts of GnRH signaling and receptor function within the context of the hypothalamic-pituitary-gonadal axis.

Endocrinology 1
Endocrinology
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Endocrinology 2
Question 1 response
GnRH is a ten amino acid peptide which is always synthesized and secreted or produced from
certain neurons called hypothalamic receptors. The hormone, that is GnRH is scattered in the
body though are secreted in clearly coordinated pulses since they are bound together by the
receptors located on gonadotrophs. The gonads secrete two hormones which their main function
is to selectively inhibit and activates the production of follicle-stimulating hormone from the
pituitary gland. The two hormones are identified as the inhibin and the activin.
The main function of the Gonadotropin-releasing hormone is to limit the release or
production of the follicle-stimulating hormone and luteinizing hormone from the anterior
pituitary. The function of the two hormones that are follicle-stimulating hormone and luteinizing
hormone is to initiate and maintain the reproductive function in the ovaries and testes.
To summarize, the secretion or production of Gonadotropin-releasing hormone occurs clearly
in coordinated pulses though they are found scattered in the hypothalamus can be linked by the
availability of the receptors located in the gonadotrophs which bind the scattered hormone for
clear coordination in the body.

Endocrinology 3
Question 2 response
The gonadotropin-releasing hormone receptors are located on the surface of the pituitary
gonadotrope cells and also in the ovary, breast and prostate. The receptors are primarily located
in the pituitary where it elicits the action of gonadotropin-releasing hormone upon its release
from the hypothalamus.
The gonadotropin-releasing hormone can be described as weird since it lacks cytoplasmic
carboxyl-terminal tail but has amino acid sequence motifs which are responsible for eliciting the
actions of the gonadotropin-releasing hormone in the body. The absence of the cytoplasmic
carboxyl-terminal tail in the receptors enables the presence of the membrane-spanning domain
which helps to convey the ligand-binding signal to the cytosolic surface of the receptor for
efficient effective transfer of cellular signals across the membrane. With the help of the
membrane-spanning domain trait possessed by the receptors, the secretion of the gonadotropin-
releasing hormone will be clear due to the binding of the hormones together in the pituitary
gland.
Another reason for gonadotropin-releasing hormone receptors being described as weird is its
ability to bind together the hormone in the hypothalamus for effective production. The receptors
are able to link the hormone in the hypothalamus for a clear production and stimulation of the
two hormones that is FSH and LH due to the absence of a cytoplasmic carboxyl-terminal tail.