Evidence that potassium deficiency induces growth retardation through reduced circulating levels of growth hormone and insulin-like growth factor I.
Growth retardation and impaired protein synthesis are major characteristics of potassium (K)-deficiency in animals and man. We have evaluated the effect of K-deficiency on growth, serum growth hormone (s-GH), insulin-like growth factor I (s-IGF-I), and insulin (s-insulin) in young rats. After 10 days on K-deficient fodder, 4 1/2-week-old rats showed a 54% reduction in serum potassium (s-K) and a weight gain that was reduced by 97%, compared with pair-fed controls. In addition, tail length, tibia length, and muscle weight of soleus in K-depleted animals were all significantly reduced compared with pair-fed controls. The growth retardation was accompanied by a 46% reduction in s-IGF-I, while s-insulin showed no decrease. K-repletion in animals depleted for 7 days showed complete normalization of s-K within 24 hours, in addition to a significant increase in both s-IGF-I and weight. In 4-week-old rats maintained on K-deficient fodder with variable K-content (1 to 260 mmol/kg) for 1 week, a strong correlation between the K-content of fodder and s-IGF-I could be established (r = .88, P less than .001), as well as between s-IGF-I and weight gain (r = .90, P less than .001). Furthermore, a stepwise reduction in basal s-GH was seen with the graded reduction of dietary K-content.(ABSTRACT TRUNCATED AT 250 WORDS)
Flyvbjerg
A
A
Medical Department M (Diabetes and Endocrinology), Aarhus Kommunehospital, Denmark.
Dørup
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I
Everts
M E
ME
Orskov
H
H
D000375:Aging / Q000097:blood; D000818:Animals; D001835:Body Weight; D004032:Diet; D004305:Dose-Response Relationship, Drug; D005260:Female; D006130:Growth Disorders / Q000209:etiology*; D013006:Growth Hormone / Q000097:blood*; D013007:Growth Hormone-Releasing Hormone / Q000494:pharmacology; D007328:Insulin / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D011188:Potassium / Q000008:administration & dosage / Q000494:pharmacology; D011191:Potassium Deficiency / Q000097:blood / Q000150:complications*; D051381:Rats; D011919:Rats, Inbred Strains
D007328:Insulin; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone; D011188:Potassium