MECHANISMS OF HORMONE ACTION

Mechanisms of hormone action.

Circulating hormones play an important role in regulating the flux through metabolic pathways. In general, hormones regulate either the activity of key enzymes of metabolism or the activity of protein transport systems such as those found in the plasma membrane and in the inner mitochondrial membrane. Little is known about the mechanism of action of hormones on transport systems, so the discuss...

Mechanisms of Hormone Action

3.1. How Hormones Change Their Target Cells Hormones are chemical messengers that invoke profound changes within target cells. There are two fundamental mechanisms by which such changes occur: • Activation of enzymes and other dynamic molecules: Most enzymes shuttle between conformational states that are catalytically active versus inactive, on versus off. Many hormones affect their target cell...

Mechanisms of thyroid hormone action.

Our understanding of thyroid hormone action has been substantially altered by recent clinical observations of thyroid signaling defects in syndromes of hormone resistance and in a broad range of conditions, including profound mental retardation, obesity, metabolic disorders, and a number of cancers. The mechanism of thyroid hormone action has been informed by these clinical observations as well...

Molecular mechanisms of steroid hormone action.

Mechanism of Action of the Thyroid Hormone on the Heart

SUMMARY  The foliowing cardiac effects may be at­tributed to thyroxin:  1-Thyroxin augments all anaerobic pro­cesses in the body includ::ng the heart, and decreases the glycogen content of the heart ( 1, 2, 5, 27). The resistance of the heart to anoxia is increased in hyperthyroidism ( 25). 2- Thyroxin influences the cardiac weight and prevents cardiac atrophy (3, 8, 10, 11, 19, 20, 21, 30...