Effects of human placental lactogen and growth hormone on the production of insulin and somatomedin C/insulin-like growth factor I by human fetal pancreas in tissue culture.
We have investigated the ability of glucose, human GH and human placental lactogen (hPL) to alter the content and release of somatomedin C/insulin-like growth factor I (SM-C/IGF-I), and the biosynthesis, content and release of insulin from cultured human fetal pancreas. Fetal pancreatic explants obtained from glands following prostaglandin-induced abortion between 12 and 21 weeks of gestation were maintained in free-floating culture for 3-5 days before the experiments. The explants were then cultured for 3 days in medium containing either 2.7 or 16.7 mmol glucose/l with or without GH (4.5 or 45.5 nmol/l) or hPL (4.6 or 46.5 nmol/l). Serum-free medium from the final 24 h of culture was collected and SM-C/IGF-I and insulin were measured radioimmunologically in both conditioned medium and tissue explants extracted with acid ethanol. Insulin biosynthesis, determined by immunoprecipitation of [3H]leucine incorporated into insulin, was not significantly altered by any experimental variable. Incubation in the presence of 16.7 mmol glucose/l caused an increase of insulin release from explants, but had no consistent action on insulin content, compared with medium containing 2.7 mmol glucose/l. The pancreatic content and release of SM-C/IGF-I were independent of these glucose concentrations. Neither GH nor hPL altered insulin or SM-C/IGF-I content or release in the presence of the lower glucose concentration. At the higher glucose concentration, 45.5 nmol GH/l did not alter insulin release but caused a significant increase in SM-C/IGF-I content.(ABSTRACT TRUNCATED AT 250 WORDS)
Swenne
I
I
Hill
D J
DJ
Strain
A J
AJ
Milner
R D
RD
D046508:Culture Techniques; D005947:Glucose / Q000494:pharmacology; D013006:Growth Hormone / Q000494:pharmacology*; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D010179:Pancreas / Q000187:drug effects / Q000196:embryology* / Q000378:metabolism; D010928:Placental Lactogen / Q000494:pharmacology*; D013002:Somatomedins / Q000378:metabolism*
D007328:Insulin; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D010928:Placental Lactogen; D005947:Glucose