In Vitro Biosynthesis of Calcitonin

Calcitonin Activity of Particulate Fractions of the Ovine Thyroid Gland

“…Sorgente (1969) demonstrated that a calcium concentration of 45 mg/100 ml, a concentration four times greater than a physiological calcium level, enhanced the biosynthesis and release of CT from thyroid slices in biosynthetic media. However, he did not determine the influence of a low calcium concentration on hormone biosynthesis and release.…”

“…-129- Sorgente (1969) had demonstrated that a very high calcium concentration (45 mg/100 ml) in the incubation media was accompanied by an increase in both synthesis and release of CT from ovine thyroid slices. It was therefore a possibility that a tracer amino acid, such as glycine-C-14 (one of the prominent amino acids of ovine CT), could be incorporated preferentially into the subcellular fraction exhibiting hypocalcemic activity.…”

“…In vitro biosynthetic media containing either slices or homogenates of such endocrine tissues as the hypothalamus (Takabatake and Sachs, 1964), anterior pituitary (Adiga et al, 1965), parathyroid glands (Hamilton andCohn, 1969 andHamilton !! al., 1971), and thyroid glands (Sorgente, 1969 andRadde et al, 1970) have been utilized to monitor the biosynthesis and release of hormones. These endocrine tissues exhibited the physiological regulatory mechanism in in vitro biosynthetic media which is typical of the gland in vivo, thereby providing a valuable insight into the factors involved in the physiological regulation of hormone synthesis and release.…”

“…Pertinent to this investigation, Sorgente (1969) utilized an in vitro biosynthetic medium containing thyroid gland slices in an effort to establish the role of calcium and magnesium ion at the tissue level on the synthesis and release of CT. Sorgente's biosynthetic media contained ovine thyroid slices which were incubated (4 hr, 37° C) with glycine-C-14 in Krebs-Ringer bicarbonate buffer containing glucose (320 mg/100 ml) and all the amino acids of calcitonin (20 mg/l). The calcitonin, which was isolated by salt precipitation from incubated thyroid slices, was assayed for hypocalcemic activity in rats.…”

“…Takabatake and Sachs (1964) by chromatography, polyacrylamide gel electrophoresis, and rat bioassay. Sorgente (1969) utilized an in vitro biosynthetic medium containing sheep thyroid slices to establish the role of varying calcium and magnesium ion concentrations on the synthesis and release of calcitonin. The incorporation of glycine-C-14 into ovine calcitonin was directly related to the calcium concentration of the incubation medium.…”