it has been well established that the secretions of thyroid hormones and growth hormone (gh) isunder the regulation of different neurotransmitters. the goal of this study was to determine whethersubstance-p, as a neurotransmitter, regulates the mean plasma concentrations of thyroxin (t4),triiodothyronine (t3), gh, milk amount and constituents in sanan goats. nine sanan goats were randomlydivide...

High ambient temperature is the major constraint on Buffalo productivity. The aim of this study was to evaluate the reproductive performance and thyroid gland function in winter and summer seasons in Khuzestan buffalo bulls. Six male indigenous buffaloes of Khuzestan with nearly the same age (2-3 years old) and weight were used. Semen and blood samples through jugular vein were collected, every...

The aim of this study was to evaluate total iodine, triiodothyronine (T3) and thyroxine (T4) status in the blood serum of Holstein cows on six farms in central Iran. Total iodine, T3 and T4 concentrations were measured in 90 blood serum samples (15 per farm). Mean concentrations of total iodine (38.80 ± 1.52 µg/l) and T3 (1.57 ± 0.10 nmol/l) were lower but the mean concentration of T4 (45.60 ± ...

THYROID HORMONES have profound effects on the growth, development, and metabolism of many tissues of higher organisms [1]. Although the biochemical bases of these effects are not fully understood, the regulation of protein synthesis is a primary event [1]. After binding to nuclear receptors, thyroid hormones control the accumulation of specific mRNA molecules that code for the synthesis of spec...

Thyroid hormone (T3 and T4) is secreted from the thyroid gland, and is known to reduce the level of serum thyrotropin (thyroid-stimulating hormone, TSH) in the pituitary gland (Sarapura et al., 2002; Shupnik et al., 1989) (Fig. 1A). This is a typical example of negative feedback between the pituitary and endocrine organs, and is a key component of thyroid hormone homeostasis. TSH is one of the ...

In order to define the patterns of TSH, T4, T3, rT3, GH and cortisol during the estrous cycle of sheep, pluriparous and primiparous ewes were synchronized with progestagen-impregnated pessaries (Veramix) at the start of the normal breeding season. After the pessaries were removed (day 0), daily blood sampling was carried out in cannulated ewes during the ovulatory cycle. Hormonal analyses of TS...

To determine the effect of ethanol on peripheral metabolism of T4, deiodinative clearance of T4 and serum concentration of T4, T3 and rT3 were measured in rats isotopically equilibrated with T4. Ethanol 8 g/Kg weight/day was given for 3 days to fasted rats and the results were compared with those normally fed or totally fasted animals. In fasted rats, deiodinative clearance of T4 and serum T4 a...

The thyroid hormones, thyroxine (T4) and triiodothyronine (T3), are essential for normal growth and development of the fetus. Their bioavailability in utero depends on development of the fetal hypothalamic-pituitary-thyroid gland axis and the abundance of thyroid hormone transporters and deiodinases that influence tissue levels of bioactive hormone. Fetal T4 and T3 concentrations are also affec...

Iodide (I-) is a trace element (0.0001% lithosphere) that is an important constituent of thyroid hormones. The iodide-containing T3 and T4 are crucial for normal development and the proper functioning of numerous metabolic pathways in probably all adult tissues. The biosynthesis of T3 and T4 involves thyroid specific proteins, found predominantly but not exclusively in the thyroid tissue. The p...

Background: The thyroid gland secrete the hormone thyroxin (T4) and triiodothyronine (T3). They have a profound effect on the metabolism of hormones. The aim of this study was to servey the effect of the extract of plant root barberry on the amount of thyroid hormone in rat having hypercholesterolemia. Materials and Methods: In this experimental study, 40 Wistar rats were divided into 5 groups ...