TSH is a dependable marker of thyroid function.

 

·    Why we should at all tests for TSH and not Free T 4 or Free T4 –which are direst reflection of thyroid activity? Why so reliance on TSH which is an indirect measurement of thyroid function .In fact TSH is a function of basophils of adeno hypophysis.

·    Ans: Because levels of thyroid-stimulating hormone (TSH) are sensitive to excessive or deficient levels of circulating thyroid hormone, and because most disorders of hyperthyroidism and hypothyroidism are related to dysfunction of the thyroid gland, TSH levels are used to screen for these disorders. The most common thyroid abnormalities in women, autoimmune thyroid disorders, represent the combined effects of the multiple antibodies produced.

·    Severe primary hypothyroidism is associated with amenorrhea or anovulation. The classic triad of exophthalmos, goiter, and hyperthyroidism in Graves’s disease is associated with symptoms of hyperthyroidism.

Source of Trophic hormones and Kinds of cells in anterior Pitutary The differential staining pattern described above is a reflection of the type of hormonal content of the cells.

Acidophils	Cells that contain the polypeptide hormones: Somatotropes which produce growth hormone Lactotropes which produce prolactin
Basophils	Cells that contain the glycoprotein hormones: Thyrotropes which produce thyroid stimulating hormone Gonadotropes which produce luteinizing hormone or follicle-stimulating hormone Corticotropes which produce adrenocorticotrophic hormone Due the high carbohydrate content of the hormones within acidophils, they also stain bright purple with PAS stains.
Chromophobes	These are cells that have minimal or no hormonal content. Many of the chromophobes may be acidophils or basophils that have degranulated and thereby are depleted of hormone. Some chromophobes may also represent stem cells that have not yet differentiated into hormone-producing cells.

Although classification of cells as acidophils or basophils is useful in some situations, specific identification of anterior pituitary cells requires immunostaining for the hormone in question.

In addition to differential staining characteristics, the size of secretory granules varies among different types of cells in the anterior pituitary. Somatotropes and lactotropes tend to have the largest size granules. The electron microscopic image below of ovine adenohypophysis depicts cells with several densities and sizes of granules.

The term "basophil" is used include the following cell types: corticotropes (adrenocorticotropic hormone (ACTH) and related peptides producing cells) thyrotropes (thyroid stimulating hormone (TSH) producing cells) gonadotropes (luteinizing hormone (LH) and follicle stimulating hormone (FSH) producing