Androgen Androgen An androgen (from Greek "andr-", the stem of the word meaning "man") is any natural or synthetic steroid hormone which regulates the development and maintenance of male characteristics in vertebrates by binding to androgen receptors. This includes the embryological development of the primary male sex organs, and the development of male secondary sex characteristics at puberty. Androgens are synthesized in the testes, the ovaries, and the adrenal glands. Androgens increase in both boys and girls during puberty. The major androgen in males is testosterone. Dihydrotestosterone (DHT) and androstenedione are of equal importance in male development. DHT "in utero" causes
Thyroid hormone receptor Thyroid hormone receptor The thyroid hormone receptor (TR) is a type of nuclear receptor that is activated by binding thyroid hormone. Among the most important functions of thyroid hormone receptors are regulation of metabolism and heart rate. In addition, they play critical roles in the development of organisms. Thyroid hormone receptors regulate gene expression by binding to hormone response elements (HREs) in DNA either as monomers, heterodimers with retinoid X receptor (RXR; which in turn is activated by binding to 9-"cis"-retinoic acid) or as homodimers. However TR/RXR heterodimers are the most transcriptionally active form of TR. In the absence of