Ecdysteroid synthesis

50) During a stressful interval
A) TSH stimulates the adrenal cortex and medulla to secrete acetylcholine.
B) the alpha cells of islets secrete insulin and simultaneously the beta cells of the islets secrete glucagon.
C) ACTH stimulates the adrenal cortex, and neurons of the sympathetic nervous system stimulate the adrenal medulla.
D) the posterior pituitary gland secretes more growth hormones.
E) the calcium levels in the blood are increased due to actions of two antagonistic hormones, epinephrine and norepinephrine.

In the Drosophila melanogaster cell line Kc-H, ecdysteroid hormone treatment causes increased relative synthesis of three ecdysteroid-inducible polypeptides (EIPs), named according to their molecular weights (in kilodaltons) EIP 40, EIP 29 and EIP 28. Increased synthesis of the EIPs is detectable within 45 min (EIP 28) or 75 min (EIPs 40 and 29), is maximal at 4-8 hr and continues for almost 2 days. During this period no other major changes in protein synthesis are discernible using one-dimensional gels. At maximum, EIP 28 synthesis is elevated at least 10 fold above its basal level, and EIPs 40 and 29 somewhat less. EIP induction is ecdysteroid-specific and is detectable in the presence of 10(-8) M 20-hydroxyecdysone. It does not occur in hormone-resistant cells. Apparently identical polypeptides are inducible in another ecdysteroid-responsive cell line, Schneider's line 3. Because EIP synthesis is an early and substantial response to ecdysteroids, this is a promising system for the study of steroid hormone action.

Ecdysteroid synthesis

ecdysteroid synthesis


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