Thyroid hormones regulate growth by several mechanisms. In addition to their negative feedback effect on the stimulatory hormones thyrotropin-releasing hormone (TRH) and thyrotropin (TSH), thyroid hormones also regulate their receptors in various physiological and pathological conditions. Up-regulation and down-regulation of the thyroid receptors fine-tune the biological effects exerted by the ...

Pituitary growth hormone (GH) is not a single molecular species, but a whole set of similar molecules, the individual specific characteristics of which constitute the polymorphism of this hormone. The present paper deals mainly with various forms of human GH, called "variants", and touches on this polymorphism in other species as well. The 22 K variant (MW = 22,000 daltons) is the predominant f...

The human body is composed of many systems and organs that work together to ensure our well-being survival. Hormones are the messengers allow communicate. thyroid a butterfly-shaped gland located in neck uses iodine from diet (mainly present seafood) produce hormones: thyroxine (T4) triiodothyronine (T3). hormones very important for brain development, growth, metabolism. A lack impairs producti...

Growth regulators are chemicals that alter the growth and development of plants. They may be natural or artificial, and typically they are active at very low concentrations. The most important plant growth regulators are the hormones, auxin, gibberellin, ethylene, cytokinin, and abscisic acid. Other growth regulators often act by modifying the action of the natural hormones. For example, naphth...

The occurrence of mammalian sex hormones and their physiological role in plants is reviewed. These hormones, such as 17beta-estradiol, androsterone, testosterone or progesterone, were present in 60-80% of the plant species investigated. Enzymes responsible for their biosynthesis and conversion were also found in plants. Treatment of the plants with sex hormones or their precursors influenced pl...

Small-molecule hormones govern every aspect of the biology of plants. Many processes, such as growth, are regulated in similar ways by multiple hormones, and recent studies have revealed extensive crosstalk among different hormonal signaling pathways. These results have led to the proposal that a common set of signaling components may integrate inputs from multiple hormones to regulate growth. ...