In vitro effect of insulin and insulin-like growth factor-I on cell multiplication and adrenocorticotropin responsiveness of fetal adrenal cells.
The present study examined the effects of both insulin and insulin-like growth factor-I (IGF-I) on cell division and specific functions of cultured adrenocortical cells from 100- to 122-day-old ovine fetuses. When culture was performed in a serum-free medium containing transferrin and ascorbic acid, the number of cells increased only slightly (1.2-fold) over a 4-day period. Addition of insulin or IGF-I in the culture medium enhanced the number of cells counted on Day 5. The effect of both peptides was dose-dependent, but 10 ng/ml IGF-I was as potent as 10 micrograms/ml insulin. The acute cyclic adenosine 3',5'-monophosphate (cAMP) and steroidogenic responses to adrenocorticotropin (ACTH1-24) decreased in fetal cells cultured in the absence of insulin or ACTH. Insulin at micromolar concentrations not only prevented this decrease but enhanced the acute ACTH1-24-induced cAMP output on Day 5 over that observed on Day 2. Treatment of fetal cells for 4 days with increasing concentrations of insulin or IGF-I enhanced the acute cAMP and steroidogenic responses (3- to 4-fold) to ACTH1-24 over that of control cells. The ED50 of IGF-I was about 3 ng/ml (congruent to 0.4 nM) whereas that of insulin was about 10 ng/ml (1.7 nM). However, a second plateau was apparent at concentrations of insulin above 1 microgram/ml. The acute cholera toxin stimulation of cAMP production of cells cultured in the absence of insulin or ACTH.(ABSTRACT TRUNCATED AT 250 WORDS)
Naaman
E
E
INRA, Station de Physiologie de la Reproduction, URA CNRS 234, Nouzilly, France.
Chatelain
P
P
Saez
J M
JM
Durand
P
P
D000311:Adrenal Glands / Q000187:drug effects* / Q000196:embryology / Q000254:growth & development; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology*; D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology; D002478:Cells, Cultured; D003345:Corticosterone / Q000096:biosynthesis; D000242:Cyclic AMP / Q000096:biosynthesis; D004357:Drug Synergism; D066298:In Vitro Techniques; D007328:Insulin / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D008938:Mitosis / Q000187:drug effects; D012756:Sheep; D013002:Somatomedins / Q000494:pharmacology*; D014168:Transferrin / Q000494:pharmacology
D007328:Insulin; D013002:Somatomedins; D014168:Transferrin; D007334:Insulin-Like Growth Factor I; D000324:Adrenocorticotropic Hormone; D000242:Cyclic AMP; D001205:Ascorbic Acid; D003345:Corticosterone