Related Experiment Video
Updated: Aug 9, 2026

An Ex vivo Culture System to Study Thyroid Development
Published on: June 6, 2014
Testosterone and estradiol differentially regulate thyroid growth in Wistar rats from immature to adult age
S K Banu1, J A Arosh, P Govindarajulu
1Department of Endocrinology, Dr. ALM. PG. Institute of Basic Medical Sciences, University of Madras, Taramani, Chennai, India.
Abstract:
Experimental and clinical data from cancerous thyroid tissue suggest gender as one of the major factors influencing thyroid growth. However, there is not much information on the effect of sex steroids on the normal development and growth of the thyroid. The aim of the present study was to examine the effect of sex steroids on thyroid growth, serum TSH and TSH receptors in the thyroid, at various stages of sexual maturation. Normal Wistar male and female rats from immature to adult age (day 21, 30, 45, 60 and 160 post partum (PP)) were used in the present study. One group of rats was gonadectomized (GDX) (Group II); another 2 groups of GDX rats (Groups III and IV) were treated with replacement doses (i.e. physiological amounts) of either testosterone or estradiol. Thyroid growth indices (thyroid weight, concentration of DNA, mitotic index and numerical density of thyrocytes), serum TSH and concentration of TSH receptors in the thyroid were assessed. It is concluded from the present study that (i) sex steroids influence thyroid growth by interfering with the secretion of TSH and regulating its receptor number in the thyroid (ii) while testosterone facilitates the mitogenic activity of the thyroid gland of rats irrespective of sex and age, estradiol plays a gender-specific stimulatory role on thyroid growth.
Related Concept Videos
Hormones and Bone Tissue
Hormones That Influence Osteoblasts and/or Maintain the Matrix
Several hormones are necessary for controlling bone growth and maintaining the bone matrix. The pituitary gland secretes growth hormone (GH), which, as its name implies, controls bone growth. This happens in several ways: first, it triggers chondrocyte...
Target Cell Response to Hormones
Notably, the cellular response can be regulated by altering the number of receptors expressed in the cell. For example, prolonged exposure to elevated hormone levels results in a gradual decline or down-regulation in the number of receptors for that specific hormone on the cell surface. Conversely, in response to low hormone levels, cells may use up-regulation, producing an...
Synthesis and Regulation of Thyroid Hormones
Upon reaching the thyroid gland, TSH stimulates the follicular cells' active uptake of iodide ions from the blood. The ions diffuse to the apical surface of the cells and are oxidized to iodine. The iodine is then...
Functions of Thyroid Hormones
TH is indispensable for the normal development and maturation of the skeletal, muscular, and nervous systems during fetal and childhood growth. It facilitates bone mineral turnover and regulates protein synthesis in developing tissues, contributing significantly to overall growth and...
Testosterone: Functions and Regulation
Signs of Puberty

