Autoradiography of Manganese: Accumulation and Retention in the Pancreas

Abstract

By means of whole‐body autoradiography, the general distribution of 54MnCl2 was studied in mice and a Marmoset monkey. High accumulation and retention were observed in the pancreas in both species. Gamma counting experiments in mice after a single intravenous injection of 54MnCl2 showed that the level in the pancreas exceeded that of the liver at all survival times (20 min. — 30 days). Also in the monkey, the concentration in the pancreas exceeded that of the liver, and the pancreas had the highest tissue/liver ratio of the organs measured at 24 hours after injection. The high uptake and long retention in the pancreas suggest that manganese is of importance for the pancreatic function but also that the pancreas may be a target organ for manganese toxicity. Positron tomography, using 11C‐labelled amino acids, has been found to be a promising diagnostic technique for the study of pancreatic disease. Positron emitting manganese isotopes may be worth further studies as possible agents for pancreatic imaging.

Anatomy, Functionality, and Neuronal Connectivity with Manganese Radiotracers for Positron Emission Tomography

“…These results are consistent with previous MRI studies in rodents [3][4]. Systemic administration of Mn-54 (t 1/2 = 312.5 days) in mice and monkeys was also reported to result in high accumulation of manganese in the kidney, liver, heart, pancreas and salivary glands in the days following administration [23][24]. Interestingly, the pancreas showed the highest level of radiotracer after 24 h in mice and monkeys [24].…”

“…2b). This is in agreement with previous reports showing that Mn 2+ is cleared from the blood very rapidly over a course of minutes after administration [2,24]. In the data shown in Fig.…”

“…Systemic administration of Mn-54 (t 1/2 = 312.5 days) in mice and monkeys was also reported to result in high accumulation of manganese in the kidney, liver, heart, pancreas and salivary glands in the days following administration [23][24]. Interestingly, the pancreas showed the highest level of radiotracer after 24 h in mice and monkeys [24]. Recent studies with [ 52 Mn]Mn 2+ and [ 51 Mn]Mn 2+ also showed similar distribution of the radiotracer in the rodent body [33,35,44].…”

“…Radioactive manganese tracers have previously been used in physiologic studies, raising the possibility of obtaining information typically derived from MEMRI by using positron emission tomography (PET) in lieu of MRI. Manganese-54, a gamma-emitter (Mn-54, t 1/2 = 312.5 days) has been used to study the accumulation and retention of manganese, after dissection, of body tissues in mice and monkeys [23][24] and to trace its distribution in specific neuronal connections in the brain of rats [25][26][27]. In the late 1960's Mn-54 was given intravenously to healthy human volunteers to study its whole body retention [28][29], with limited clinical use due to its long half-life and high gamma energy.…”

Manganese-Enhanced Magnetic Resonance Imaging as a Diagnostic and Dispositional Tool after Mild-Moderate Blast Traumatic Brain Injury

“…10,[15][16][17][18] When administered orally or parenterally, Mn 2+ accumulates in all body tissues and is excreted via the biliary system, [19][20][21] a condition that explains its use, in a chelated form, to assess liver and pancreatic pathologies in Europe. 19,[22][23][24] After systemic injection, Mn 2+ enters the brain promptly through the CSF, thereby first reaching the ventricles, choroid plexus and regions that lack a blood brain barrier (BBB) such as the pituitary and pineal glands and the median eminence. After crossing the BBB, Mn 2+ can be incorporated into brain cells with active transport through calcium-channels and other metal transporters [25][26][27][28][29] and it can persist inside cells for weeks or months.…”