Biomaterial Database

Effect of hyperthermia on thyroid structure in the late gestation fetal lamb. 1990

P Andrianakis, and R G Stephenson, and D W Walker

Department of Physiology, Monash University, Clayton, Australia.

This study examined the effect of hyperthermia in late gestation on fetal thyroid structure. Mild heat stress (increase of ewe's rectal temperature to 40.4 degrees C) caused significant changes of fetal thyroid structure. Intra-follicular colloid area was significantly larger in the heat-stressed group (2,532 +/- 181 microns2) compared to a control group where rectal temperature of the ewe was within the normal range (1,660 +/- 188 microns2; p less than 0.01). Epithelial cell height was significantly reduced (2.5 +/- 0.19 vs. 4.8 +/- 0.26 microns; p less than 0.01). Fetal plasma glucose concentrations were significantly lower in the heat-stressed group (0.7 +/- 0.07 mmol/l) compared to the non-heated group (1.0 +/- 0.11 mmol/l; p less than 0.05). We suggest that the fetal thyroid gland in sheep is responsive to environmental temperature changes and is important in the neuroendocrine regulation of fetal body temperature. Fetal hypoglycaemia may also contribute to the changes in fetal thyroid gland by altering the peripheral utilization of thyroid hormone. Such changes, if prolonged, may contribute to the decreased rate of fetal growth and maturation associated with chronic heat stress in sheep.

UI	MeSH Term	Description	Entries
D009929	Organ Size	The measurement of an organ in volume, mass, or heaviness.	Organ Volume,Organ Weight,Size, Organ,Weight, Organ
D011247	Pregnancy	The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.	Gestation,Pregnancies
D001786	Blood Glucose	Glucose in blood.	Blood Sugar,Glucose, Blood,Sugar, Blood
D001835	Body Weight	The mass or quantity of heaviness of an individual. It is expressed by units of pounds or kilograms.	Body Weights,Weight, Body,Weights, Body
D005260	Female		Females
D005314	Embryonic and Fetal Development	Morphological and physiological development of EMBRYOS or FETUSES.	Embryo and Fetal Development,Prenatal Programming,Programming, Prenatal
D006358	Hot Temperature	Presence of warmth or heat or a temperature notably higher than an accustomed norm.	Heat,Hot Temperatures,Temperature, Hot,Temperatures, Hot
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012756	Sheep	Any of the ruminant mammals with curved horns in the genus Ovis, family Bovidae. They possess lachrymal grooves and interdigital glands, which are absent in GOATS.	Ovis,Sheep, Dall,Dall Sheep,Ovis dalli
D013961	Thyroid Gland	A highly vascularized endocrine gland consisting of two lobes joined by a thin band of tissue with one lobe on each side of the TRACHEA. It secretes THYROID HORMONES from the follicular cells and CALCITONIN from the parafollicular cells thereby regulating METABOLISM and CALCIUM level in blood, respectively.	Thyroid,Gland, Thyroid,Glands, Thyroid,Thyroid Glands,Thyroids