Hypoglycemic effects of insulin-like growth factor-1 in experimental uremia: can concomitant growth hormone administration prevent this effect?
The risk of hypoglycemia limits the clinical application of insulin-like growth factor-1 (IGF-1). Our studies aimed to evaluate the mode of occurrence as well as the prevention of this side effect. Acute administration (i.v. infusion) of IGF-1 in subtotal nephrectomized uremic (U), sham-operated ad libitum fed control (C) and sham-operated pair-fed control (P) rats led to hypoglycemia, though more expressed in P. Serum glucose levels decreased within 60 min after the IGF-1 administration by 40% in U, by 45% in C and by 52% in P (p < 0.05, U vs. P). Chronic administration (7 days) of 1, 4 and 8 mg/kg/day IGF-1 in U rats led to hypoglycemia in an increasing manner as the dose of IGF-1 increased. On the first day, 2 h after injection, serum glucose levels were 116.5 +/- 8.6, 110.4 +/- 12.4, 60,3 +/- 19.2 and 50.6 +/- 18.3 mg/dl, respectively (p < 0. 01). One week later, IGF-1 therapy proved to be less hypoglycemic in all the groups. On day 7, 2 h after injection the serum glucose levels were 118.9 +/- 23.8, 89.0 +/- 23.9 and 66.0 +/- 32.0, respectively (in comparison to day 1 for 4 and 8 mg/kg/day IGF-1 p < 0.05). The combined effect of 4 mg/kg/day IGF-1 and 10 IU/kg/day growth hormone (GH) was also studied in U and P animals. Two hours after the first injections of IGF-1 serum glucose levels decreased in U from 120.0 +/- 11.3 to 49.2 +/- 21.6 mg/dl, while IGF-1 plus GH decreased the glucose level from 122.0 +/- 15.5 to 81.3 +/- 24.7 mg/dl (p < 0.05 IGF-1 vs. IGF-1 + GH). The hypoglycemic effect of IGF-1 was less expressed by long-term treatment and simultaneous administration of GH overcame the glucose-lowering effect of IGF-1 (serum glucose levels on day 11 one hour after the injections: 73.7 +/- 15.3 mg/dl with IGF-1, and 111.0 +/- 7.8 mg/dl with IGF-1 + GH). Methylprednisolone (MP) did not significantly alter the former effects of IGF-1 and GH. In summary, IGF-1 leads to hypoglycemia in control and uremic rats in a dose-dependent manner. This effect becomes less expressed after prolonged administration. GH attenuates the hypoglycemic effect of IGF-1. This suggests that the combined GH and IGF-1 treatment is more effective and less dangerous in correcting uremic growth failure.
Kovacs
G T
GT
2nd Department of Pediatrics and Institute of Patophysiology and International Nephrological Research and Training Center, Semmelweis University, Budapest, Hungary. kovi@gyer2.sote.hu
Worgall
S
S
Schwalbach
P
P
Steichele
T
T
Mehls
O
O
Rosivall
L
L
D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D005260:Female; D013006:Growth Hormone / Q000008:administration & dosage / Q000627:therapeutic use*; D007003:Hypoglycemia / Q000097:blood / Q000139:chemically induced* / Q000517:prevention & control*; D007334:Insulin-Like Growth Factor I / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D051381:Rats; D017207:Rats, Sprague-Dawley; D014511:Uremia / Q000188:drug therapy*
D001786:Blood Glucose; D004338:Drug Combinations; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone