Question

Determine the identity of each of the following six unknown hormones using the autopsy data listed for each (Figures 8 through 13) compared to the controls (in Table 1 and Fig. 4).

Hormone 1 FIG. 8 Autopsy results from rats treated with hormone 1. Hormone 1 Cintact) Pituitary: 10.1 mg Thyroid: 245 mg Thymus: 250 mg Adrenals: 100 mg Seminal vesicles: 490 mg Prostate: 430 mg Testes: 3000 mg Body weight: 2009 Hormone 1 (castrate) Pituitary 10.1 mg Thyroid: 250 mg Thymus: 250 mg Adrenals: 95 mg Seminal vesicles: 410 mg Prostate: 380 mg Body weight: 1959 . What was hormone 1? • Explain your answer: Effects of Hormone 1 on Organ Size(*. - or NC) Intact rat Castrate rat Pituitary Thyroid Thymus Adrenals Seminal vesicles Prostate Testes Body weight Hormone 2 FIG. 9 Autopsy results from rats treated with hormone 2 Hormone 2 (intact) Pituitary: 9.8 mg Thyroid: 250 mg Thymus: 480 mg Adrenals: 40 mg Seminal vesicles: 900 mg Prostate: 800 mg Testes: 5700 mg Body weight: 385 g Hormone 2 castrate Pituitary: 13 mg Thyroid: 250 mg Thymus: 480 mg Adrenals: 42 mg Seminal vesicles: 412 mg Prostate: 375 mg Body weight: 2759 . What was hormone 2? • Explain your answer: Effects of Hormone 2 on Organ Size (t.- Or NC) Intact rat Castrate rat Pituitary Thyroid Thymus Adrenals Seminal vesicles Prostate Testes Body weight

Answer 1

Q.1)
Hormone 1: ACTH
ACTH stimulates the release of cortisol from the
adrenal glands; however, cortisol is only released in
the maximum amount the body can produce (physiological dose).
The increase of cortisol causes the
negative feedback mechanism to inhibit the production of ACTH from the anterior pituitary gland, which
causes a decrease in gland size. The adrenal glands
increased in weight because they were being stimulated, whereas the thymus gland had a reduction in
weight because of cortisol’s immunosuppressive action.
The thymus is the sight of lymphocyte processing and development.

Q.2)
Hormone 2: LH
LH affects the reproductive system. There was a size
increase in the testes, prostate, and seminal vesicles in
the intact rat due to the release of excess testosterone.
An increase in body weight is also seen because of the
physiological effects of testosterone.
In the castrate
rat, there were no testes for LH to stimulate nor
testosterone to be released; therefore, the size of the
prostate and seminal vesicles did not change in the
castrate rat.
The size of the pituitary gland in the intact
rat decreased in size because of the negative feedback
effects of LH.

Q.3)
Hormone 3: Testosterone
When testosterone was added from an external source,
the castrate and intact animals appeared the same.
The large increase in body weight was due to the
pharmacological doses of the androgen, causing an
increase in muscle mass (note that men are generally
bulkier than females). There was a decrease in the
testes mass because testosterone negatively feeds
back to inhibit its own release from the testes.
Similarly, the pituitary gland also decreased in size
because of the negative feedback from the testosterone.
An increase in the mass of the seminal vesicles
and the prostate was seen because testosterone functions to maintain the male reproductive system.

Q.4)
Hormone 4: TRH
The most obvious difference was the increase in
pituitary gland size due to excess stimulation by TRH.
The thyroid increased in size because TRH stimulated
the release of TSH. There was a general wasting effect
on all body organs, because hyperthyroidism causes
an increase in metabolism, thus the decrease in body
weight and organ size.
TSH does not significantly affect the reproductive organs.

Q.5)
Hormone 5: Cortisol
Cortisol causes protein degradation and lipolysis
(breakdown of fats) and, therefore, a general decrease
in body mass.

The pituitary and adrenal glands decrease in size because they are inhibited by the
negative feedback of cortisol.
The pharmacological dose of cortisol caused a large reduction of weight in the thymus gland because of its immunosuppressive action.
Cortisol does not significantly affect the reproductive organs.

Q.6)
Hormone 6: TSH
The size of the pituitary decreased because TSH
negatively feeds back to the pituitary gland and the
hypothalamus.
Only the thyroid glands increase in size with excess stimulation by TSH.
The rest of the body underwent a wasting effect due to the release of excess TH, which raised the BMR, causing the body
weight of the rat to decrease.
TSH does not affect the reproductive organs.