According to a research by scientists at the University of Bristol and the National Cancer Institute (NCI), USA, intermittent signaling by steroid hormones can affect expression of genes in rodents. This study is considered to bring considerable implications when it comes to understanding as to how steroids work besides opening up novel avenues for new therapies.
The findings of this study are published online and expected to appear in the September 2009 issue of Nature Cell Biology.
From News-Medical.Net:
Glucocorticoid hormones, which were investigated in this study, are steroid hormones secreted by the adrenal glands that are involved in a large variety of animal and human physiological responses.
Glucocorticoids act through the glucocorticoid receptor, which is expressed in almost every cell in the body and regulates genes controlling development, metabolism, and immune response.
Studies of the glucocorticoid receptor typically assess gene responses after long-term stimulation with synthetic hormones. However, such treatments may not fully replicate the actual situation in living animals because, in addition to being released from the adrenal glands in a 24-hour circadian pattern, these hormones are also released in a pulsing mode, cycling approximately every hour, in what is referred to as ultradian cycling.
In this new study, the researchers demonstrate that ultradian hormone stimulation induces the pulsed expression of genes (known as gene pulsing) over the same period, both in cultured cells and in animal models. Initially, the researchers administered corticosterone, a naturally occurring glucocorticoid hormone in rodents, in a pulsed manner to cultured mouse cells and then observed that the levels of newly synthesized RNA from glucocorticoid receptor-regulated genes tracked precisely with the hormone pulses.
Professor Stafford Lightman, head of the Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, at the University of Bristol, said that the hormone cortisol is released in pulses in rodents as well as man and the present results suggest that this hormonal pattern release is critical for sound health besides offering a novel concept for new drug design.
