Changes in muscarinic receptors and amylase secretion in regenerating acinar cells of rat pancreas.
Atrophic pancreatic acinar cells of copper-deficient rats recovered after copper supplementation. To clarify whether the recovered cells are regenerative and amylase secretion via muscarinic receptors alters, [3H]-thymidine uptake, [3H]-quinuclidinyl benzilate binding and amylase release were studied in these rats and compared with the values of 5-day-old and 21-week-old rats. The [3H]-thymidine uptake study indicated that the recovered acinar cells were regenerative. The number of muscarinic receptors in regenerating cells was equal to that in mature cells and was one third in cells of 5-day-old rats. The apparent dissociation constant of muscarinic receptors was about 0.73 x 10(-10) M for the regenerating cells, 0.65 x 10(-10) M for 5-day-old rats, and 1.70 x 10(-10) M for 21-week-old rats. Amylase release, as a percent of total amylase, was maintained relatively steady in spite of the low amylase content in regenerating cells. These observations suggest that the affinity of muscarinic receptors increases to compensate the impaired amylase synthesis in regenerating acinar cells and that their amylase secretion via muscarinic receptors is different from that in 5-day-old or mature rats.
Sumii
T
T
Third Department of Internal Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Kimura
T
T
Ogami
Y
Y
Yamaguchi
H
H
Kinjo
M
M
Ibayashi
H
H
D000681:Amylases / Q000378:metabolism*; D000818:Animals; D003300:Copper / Q000008:administration & dosage / Q000172:deficiency; D007515:Islets of Langerhans / Q000166:cytology / Q000378:metabolism*; D008297:Male; D011813:Quinuclidinyl Benzilate / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011976:Receptors, Muscarinic / Q000378:metabolism*; D012038:Regeneration; D013936:Thymidine / Q000378:metabolism
D011976:Receptors, Muscarinic; D011813:Quinuclidinyl Benzilate; D003300:Copper; D000681:Amylases; D013936:Thymidine