Iodine in biology 65% of the molecular weight of T4 and 59% of T3. The thyroid gland actively absorbs iodine from the blood to produce and release these hormones into the blood, actions which are regulated by a second hormone, called thyroid-stimulating hormone (TSH), which is produced by the pituitary gland. Thyroid hormones are phylogenetically very old molecules which are synthesized by most multicellular organisms, and which even have some effect on unicellular organisms. Thyroid hormones play a fundamental role in biology, acting upon gene transcription mechanisms to regulate the basal metabolic rate. T3 acts on small intestine cells and adipocytes to increase
Suprapedal gland the suprapedal gland of the land snail "Pomatias elegans" there are three types of gland cells: cells producing mucoproteins, cells producing proteins and cells producing sulphated mucopolysaccharides. For example, the land slug "Leidyula floridana" has gland cells in the suprapedal gland which produce weakly acidic mucopolysaccharides, neutral mucopolysaccharides and a protein. Suprapedal gland The suprapedal gland or mucous pedal gland is an anatomical feature found in some snails and slugs. It is a gland located inside the front end of the foot of gastropods. The term "suprapedal" means "above the foot". The function of this gland is to produce mucus.