Detection of insulin and insulin-like growth factors I and II in saliva and potential synthesis in the salivary glands of mice. Effects of type 1 diabetes mellitus.
The salivary glands of mammals synthesize and secrete a number of peptide growth factors that play important roles in cell/tissue homeostasis and embryonic development. Using a radioimmunoassay, insulin, insulin-like growth factor-I (IGF-I) and insulin-like growth factor-II (IGF-II) were detected in saliva from mice. Unlike epidermal growth factor (EGF), there was no sexual dimorphism in the concentrations of the insulin growth factor family. Immunohistochemical localization of IGF-I and IGF-II was confined to the duct cells of both the parotid and the submandibular glands. Reverse transcriptase-polymerase chain reaction amplification of total RNA from parotid and submandibular glands confirmed the presence of all three hormone/growth factor mRNAs in both glands. The levels of insulin and IGF-I were higher in saliva from an animal model for autoimmune type 1 diabetes, the non-obese diabetic (NOD) mouse, than in a second inbred strain, BALB/c. In contrast, the IGF-II levels were decreased relative to the BALB/c strain. With the onset of diabetes in NOD mice, insulin levels declined, while IGF-I and IGF-II levels showed trends toward lower levels of these growth factors when compared with non-diabetic animals. These changes were reflected in the concentrations from parotid and submandibular gland cell lysates.
Kerr
M
M
Department of Oral Biology, University of Florida, Gainesville 32610, USA.
Lee
A
A
Wang
P L
PL
Purushotham
K R
KR
Chegini
N
N
Yamamoto
H
H
Humphreys-Beher
M G
MG
D000818:Animals; D001483:Base Sequence; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism*; D007150:Immunohistochemistry; D007328:Insulin / Q000032:analysis*; D007334:Insulin-Like Growth Factor I / Q000032:analysis* / Q000096:biosynthesis; D007335:Insulin-Like Growth Factor II / Q000032:analysis* / Q000096:biosynthesis; D051379:Mice; D008807:Mice, Inbred BALB C; D016688:Mice, Inbred NOD; D008969:Molecular Sequence Data; D012463:Saliva / Q000737:chemistry*; D012469:Salivary Glands / Q000378:metabolism*
D007328:Insulin; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II