Changes in adrenocorticotropic hormone (ACTH) release from the cultured anterior pituitary cells of streptozotocin-induced diabetic rats.
We examined ACTH release from cultured anterior pituitary cells of streptozotocin (STZ)-induced diabetic rats. Rats 1 week after the injection of STZ (55 mg/kg, i.v.) were used as a short-term diabetic model, while rats 8 weeks after the injection of STZ were used as a long-term diabetic model. ACTH release induced by corticotropin-releasing factors (CRF) was significantly increased in the short-term diabetic rats, whereas ACTH release decreased in the long-term diabetic rats. A stimulator of adenylate cyclase, forskolin, caused marked increases in ACTH release in short-term diabetic rats, whereas it did not affect the long-term diabetic rats. An L-type Ca2+ channel agonist, BAY K 8644, did not affect ACTH release in the short-term diabetic rats, although it decreased ACTH release in long-term diabetic rats. In addition, CRF-induced ACTH release also increased in normal anterior pituitary cells cultured under high glucose conditions (25 mmol/L) for 5 d. These results suggest that the increase in the CRF-induced ACTH release from cultured anterior pituitary cells of short-term diabetic rats appears to involve the cAMP system in part. In contrast, the decrease in the CRF-induced ACTH release from the cultured anterior pituitary cells of long-term diabetic rats may indicate a change in the properties of the L-type Ca2+ channel coupled with the CRF receptor, or in the CRF receptor itself.
Gohshi
A
A
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Fukuoka University, Japan.
Honda
K
K
Tominaga
K
K
Takano
Y
Y
Motoya
T
T
Yamada
K
K
Kamiya
H
H
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D000324:Adrenocorticotropic Hormone / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D008297:Male; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013311:Streptozocin
D005576:Colforsin; D013311:Streptozocin; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone