Increased concentrations of atrial and plasma atrial natriuretic peptide in castrated male rats.
The effects of orchiectomy and testosterone replacement on the plasma concentration and the atrial stores of atrial natriuretic peptide (ANP) were studied in the rats. Male rats were orchiectomized (Orc) three weeks before replacement with testosterone propionate (TP, 20 mg/ml/kg body weight) or sesame oil for five days. Immunoreactive ANP (IR-ANP) in the extracted right atria and plasma of experimental rats was measured. Plasma ANP concentrations were 206 +/- 22, 927 +/- 151, and 264 +/- 61 pg/ml in normal control, Orc, and Orc + TP rats, respectively. ANP contents in right atria were higher in Orc (108 +/- 9 ng/mg tissue) and TP-treated Orc rats (123 +/- 9 ng/mg tissue) than in normal animals (32 +/- 7 ng/mg tissue). These results indicate an increased plasma concentration and atrial stores in the castrated male rats. Replacement of testosterone in the castrated male rats does not decrease the atrial ANP stores, but decreases the plasma ANP concentration.
Hwu
C M
CM
Department of Physiology, National Yang-Ming Medical College, Taipei, Taiwan, R. O. C.
Tsai
S C
SC
Lau
C P
CP
Pu
H F
HF
Wang
T L
TL
Chiang
S T
ST
Wang
P S
PS
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000097:blood*; D001835:Body Weight; D002369:Castration; D006325:Heart Atria / Q000378:metabolism*; D008297:Male; D009929:Organ Size; D051381:Rats; D017208:Rats, Wistar; D012669:Seminal Vesicles; D013739:Testosterone / Q000008:administration & dosage / Q000494:pharmacology
D013739:Testosterone; D009320:Atrial Natriuretic Factor