Differences in the effects of 20 K- and 22 K-hGH on water retention in rats.
Antidiuretic actions induced by two growth hormone (GH) isoforms (20 K- and 22 K-hGH; 0.2 and 2.0 mg/kg) were evaluated in rats, as fluid retention may cause oedema, one of the adverse effects of GH. Both GH isoforms (2.0 mg/kg) suppressed urine excretion in hypophysectomized rats (P< 0.01), but only the 22 K-hGH isoform (2.0 mg/kg) suppressed urine excretion in intact rats (P< 0.01). In addition, prolactin (PRL) suppressed urine excretion in intact rats (P< 0.05). In conclusion, 20 K-hGH has less potency in causing urine retention than 22 K-hGH and since 20 K-hGH is missing 15 amino acids found in 22 K-hGH, these amino acids may be important for the antidiuretic action of GH. Since prolactin suppressed urine excretion, a part of the antidiuretic action of GH may be related to PRL-R activation.
Satozawa
N
N
Medicinal Research Department, Institute of Biological Science, Mitsui Pharmaceuticals Inc., Chiba, Japan. nsatozawa@schering.co.jp
Takezawa
K
K
Miwa
T
T
Takahashi
S
S
Hayakawa
M
M
Ooka
H
H
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D004231:Diuresis / Q000187:drug effects* / Q000502:physiology; D004487:Edema / Q000139:chemically induced* / Q000503:physiopathology; D006128:Growth / Q000187:drug effects; D019382:Human Growth Hormone / Q000737:chemistry* / Q000494:pharmacology*; D006801:Humans; D007016:Hypophysectomy; D008297:Male; D008970:Molecular Weight; D010902:Pituitary Gland / Q000502:physiology; D011388:Prolactin / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000737:chemistry / Q000494:pharmacology; D014667:Vasopressins / Q000494:pharmacology; D014882:Water-Electrolyte Balance / Q000187:drug effects
D011994:Recombinant Proteins; D014667:Vasopressins; D019382:Human Growth Hormone; D011388:Prolactin