Question

1)when exposed to restraint stress as adults, prenatal stress exposed offspring demonstrate:

a) attenuated prolactin response

b) decreased corticosterone response compared to those with adrenalectomized mothers

c) elevated corticosterone response compared to those with adrenalectomized mothers

d) a and c

e) none of the answers are correct

2) Which of the following act as negative feedback elements in a cells circadian loop?

a) CLOCK-BMALI1

B) CRY-PER

C) CK1-BMAL

D) CLOCK-PER

3) Which issue is generally not associated with anabolic steroid abuse?

a) Sterility

B) Improved spatial ability

C) Acne

d) Immunosuppression

4) There appears to be an ideal range of corticosterone conc., cprresponding to inverted U-shaped curve, above or below which hippocampal-dependent spatial learning is imparied

a) true

b) false

Answer 1

1)when exposed to restraint stress as adults, prenatal stress exposed offspring demonstrate:

a) attenuated prolactin response

b) decreased corticosterone response compared to those with adrenalectomized mothers

c) elevated corticosterone response compared to those with adrenalectomized mothers

d) a and c

e) none of the answers are correct

1) a) attenuated prolactin response

In rats, it has been demonstrated that the effect of a prenatal stressor causes that adult levels of prolactine are significantly lower, whereas corticosterone levels were only marginally affected (neither decreased nor elevated). (Politch et al., 1978).

2) Which of the following act as negative feedback elements in a cells circadian loop?

a) CLOCK-BMALI1

B) CRY-PER This is correct.

C) CK1-BMAL

D) CLOCK-PER

CLOCK is a transcription factor with a helix-loop-helix motif capable of joining with the BMAL-1 protein, and this dimer can activate the expression of the Period and Timeless genes in Drosophila. These genes codify proteins that regulate circadian rhythm.

CRY-PER complex causes a transcription-translation negative feedback loop.

In Drosophila, PER (Period) dimerizes with TIM (Timeles) and this complex goes into the nucleus and inhibits the transcription factor of both genes (CLOCK/CYCLE). So, inhibition of CLOCK/CYCLE lowers PER and TIM mRNA levels, and so the proteins. CRY (cryptochrome) is a light sensitive protein which inhibits TIM in the presence of light.

In mammals, there is an analogous mechanism. PER proteins dimerizes with CRY1 or CRY2, and this PER/CRY complex inhibits CLOCK/BMAL1, which, as we said in previous question, activate the expression of PER and TIM.

CK1-BMAL dimer has a role in positive feedback (not negative). The transcription factor BMAL1 is a CK1 substrate, and increased CK1 activity has been shown to positively regulate transcription of genes under the influence of BMAL1-dependent circadian gene promoters.

3) Which issue is generally not associated with anabolic steroid abuse?

a) Sterility

B) Improved spatial ability

C) Acne

d) Immunosuppression

A misuse of anabolic steroids can cause decreased sperm production, shrinking of the testicles, testicle cancer, all of this associated to sterility. It also can cause severe acne and cyst.

Androgens affect spatial ability. Findings indicate that early androgens influence spatial and mechanical abilities, and that androgen effects on abilities may occur in part through effects on sex-typed activity interests.

Some studies have observed that the administration of Nandrolone (10 mg / Kg) to rats inhibits the in vitro activity of lymphocytes, especially of cells derived from the thymus, concluding that the administration of supra-pharmacological doses of steroids for prolonged periods damages the functionality of the thymus lymphocytes and the marrow 17. Taking this results, anabolic steroids would cause immunosuppression. But, some studies have not observed differences between the T lymphocyte populations of bodybuilders taking steroids and those of those who did not take them.

4) There appears to be an ideal range of corticosterone conc., corresponding to inverted U-shaped curve, above or below which hippocampal-dependent spatial learning is impaired.

a) true

b) false

Some early studies demonstrate that performance declines in challenging tasks when arousal falls along the extremes of being too low or high. In healthy young adults, many studies show that the HPA axis has a non-linear relationship with hippocampal-dependent spatial learning, with very low or high corticosterone levels impairing spatial learning and moderate corticosterone levels being optimal.