The Relationship Between Food, Gastro-Intestinal Hormones and Calcitonin Secretion

Abstract

The role of calcitonin (CT) in postprandial calcium homeostasis and the possibility of a gastroentero-thyroid C-cell system was studied in young pigs. When pigs were fasted for more than 36 h and then fed, the plasma calcium concentration decreased by 6\m=.\1 % over a period of 60\p=n-\120 min after a meal. Since in thyroidectomized pigs the plasma calcium concentration increased by 7\m=.\2 % when they were fed after a fast of 36 h it is suggested that increased CT secretion assists in the control of postprandial hypercalcaemia. Direct measurement of CT in peripheral plasma supported this suggestion. Because the plasma calcium concentration in an intact pig on a normal feeding regime does not change after a meal, the possibility of the involvement of one or more humoral factors in the stimulation of thyroid C-cells was investigated. Exogenous gastrin and endogenous gastrin stimulated by meat extract were both previously shown by us to increase CT secretion rate. This observation has now been extended to include other stimuli to endogenous gastrin, e.g. glycine and gastric distension. Furthermore, partially purified enteroglucagon increased CT secretion rate from perfused thyroid glands, isolated in situ. Stimulation of endogenous entero\x=req-\ glucagon by the intraduodenal administration of glucose, and probable stimulation of endogenous pancreozymin by intraduodenal fat, were both associated with an increased CT secretion rate from the thyroid gland.These results support the concept of a gastroentero-thyroid C-cell system which serves to stimulate CT secretion and thus to protect the skeleton from excessive bone resorption during periods of dietary sufficiency.

Calcitonin Levels in Chronic Renal Disease

“…Certain gastrointestinal hormones have been suspected of being secretagogues of calcitonin in man. Our own previously re ported in vitro studies with normal human thyroid tissue have demonstrated that gastrin stimulates the release of calcitonin [12], In addition, animal studies have demonstrated that gastrin also provokes the release of calci tonin in vivo [13]. In the study of Cooper et al [14] , calcitonin and gastrin were positively cor related in pig thyroid venous blood in the basal state as well as during stimulation by intragastric or intravenous calcium and intragastric acetylcholine.…”

Expression of glucagon‐like peptide 1 receptor in a murine C cell line Regulation of calcitonin gene by glucagon‐like peptide 1

“…Three different forms of GLP-1 are produced by intestinal L cells, GLP-1 (1 37), GLP-1 (7 36 amide), and GLP-1 (7-37), but only truncated forms of GLP-I are biologically active [4] as potent insulin secretagogues. The existence of a gastroentero-thyroidal axis involved in the control of calcitonin (CT) secretion was postulated 23 years ago [5]. Glucagon [6] as well as partially purified enteroglucagon were shown to stimulate the CT secretion rate in pigs [5].…”

“…The existence of a gastroentero-thyroidal axis involved in the control of calcitonin (CT) secretion was postulated 23 years ago [5]. Glucagon [6] as well as partially purified enteroglucagon were shown to stimulate the CT secretion rate in pigs [5]. We have therefore studied the effects of GLP-1 (7-37) on the secretion of CGRP and CT by the CA-77 C cell line, and on the steady-state level of their mRNAs.…”

Hormonal regulation of calcium metabolism in the newborn

“…One hour after administration of soybean oil by force-feeding, the plasma CT level was significantly increased in the 2-hour old newborn rat (Garel and Jullienne, 1977). In a 30-kg pig, the administration of intraduodenal fat was shown to stimulate CT secretion 1 h later (Swaminathan et al, 1973). However, gastric distension alone is capable of stimulating not only gastrin secretion but also CT secretion (Swaminathan et al, 1973).…”

“…In a 30-kg pig, the administration of intraduodenal fat was shown to stimulate CT secretion 1 h later (Swaminathan et al, 1973). However, gastric distension alone is capable of stimulating not only gastrin secretion but also CT secretion (Swaminathan et al, 1973). In 2-hour old fasted newborn rats, gastric distension remained without effect on CT secretion since force-feeding 0.9 p. 100 NaCI in control animals did not change the plasma CT concentration (Garel and Jullienne, 1977 (Garel and Jullienne, 1977).…”