Immunohistochemical localization of insulin-like growth factor I in the adult rat.
Rabbit antisera against native human insulin-like growth factor I (IGF-I; somatomedin C) or a synthetic tetradecapeptide, representing the carboxyterminal amino acids 57-70 of human IGF-I, were used to map immunohistochemically the distribution of IGF-I immunoreactive material in adult rats. Both antisera were specific for IGF-I, as characterized by immunoabsorption, immunoblotting and radioimmunoassay. There was no cross-reactivity to IGF-II, relaxin or pro-insulin; substances having a high degree of structural homology with IGF-I. High IGF-I immunoreactivity was observed in spermatocytes of the testis; in oocytes, granulosa and theca interna cells of the ovary during early stages of follicle development; in some lymphocytes and in reticular cells of lymphoid and hematopoietic organs; in salivary gland duct cells; in the adrenal medulla, the parathyroid gland and the Langerhans' islets. Chondrocytes in the epiphyseal and rib growth plates and at articular surfaces showed strong IGF-I immunoreactivity. Brown but not white fat cells were stained. Nerve cells in the peripheral and autonomic nervous system showed faint to intense IGF-I immunoreactivity. In contrast, neurons and neuroglial cells in the central nervous system were generally negative; motor neurons being an exception. Erythropoietic, thrombocytopoietic and myeloic cells in the bone marrow showed IGF-I immunoreactivity, but only at defined developmental stages. Hepatocytes showed faint IGF-I immunoreactivity, but became more intensely stained after pretreatment with colchicine. The present results suggest that IGF-I is synthetized by cells in several tissues and organs in the adult rat. There was an apparent association between the localization of IGF-I and cell differentiation.(ABSTRACT TRUNCATED AT 250 WORDS)
Hansson
H A
HA
Department of Histology, University of Göteborg, Sweden.
Nilsson
A
A
Isgaard
J
J
Billig
H
H
Isaksson
O
O
Skottner
A
A
Andersson
I K
IK
Rozell
B
B
D000818:Animals; D005260:Female; D007150:Immunohistochemistry; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013002:Somatomedins / Q000032:analysis*; D014781:Viscera / Q000032:analysis*
D013002:Somatomedins; D007334:Insulin-Like Growth Factor I