Effects of Manganese Deficiency and Dietary Composition on Rat Pancreatic Enzyme Content

Abstract

Recent studies show that manganese (Mn) deficiency increases pancreatic amylase content. Pancreatic adaptation to dietary composition also alters enzyme content. The present study investigated whether Mn deficiency alters pancreatic adaptation to diet. Weanling rats that were fed for 6 wk a high carbohydrate (HC) diet with less than 1 mg Mn/kg diet (Mn deficient) or 40 mg Mn/kg diet (control) were divided into three control and deficient dietary subgroups: 1) HC, 2) high protein (HP) or 3) high fat (HF). Rats were then fed these diets for 10 d. Body weights and food consumption were comparable among the groups. Pancreatic and hepatic Mn contents were significantly lower in Mn-deficient rats than in respective controls. Digestive enzymes adapted to diet in both control and Mn-deficient rats with the greatest amylase, lipase and trypsin activities in HC, HF and HP rats, respectively. Mn deficiency resulted in significantly greater amylase activity in HC and HP groups and lipase activity in only the HF group than in respective controls. These data suggest that Mn participates in the regulation of pancreatic amylase content and in the adaptive response of pancreatic lipase to dietary fat.

Distribution of manganese in rat pancreas and identification of its primary binding protein as pro-carboxypeptidase B

“…In mammalian tissues, pancreas contains a relatively high level of manganese (Mn). Mn is believed to be an essential trace element for pancreatic exocrine and endocrine functions, since Mn deficiency impairs these functions, including an elevation of tissue amylase content [1,2] and an abnormal insulin secretion that results in glucose intolerance [3,4]. In addition, Mn is known to stimulate protein synthesis [5,6] and to regulate amylase release [7] in isolated pancreatic acini.…”

Optic Nerve Changes in Manganese-deficient Rats

“…This means that when the CNS is destroyed it never recovers. One of the biochemical functions of manganese is its role in metalloenzymes such as manganese-superoxide dismutase (Mn;SOD) (Malecki et al, 1994 ;Malecki and Greger, 1996 ;Utter, 1976 ;Werner, Korc and Brannon, 1987). In the brain Mn;superoxide dismutase activity was reported to be reduced by 50 % in Mn-deficient mice (de Rosa et al, 1980), and it reached normal levels when these mice were fed a Mnsupplemented diet.…”