The changes in
adrenocorticotropin (
ACTH) release before, during and after sympathetic
nerve degeneration following superior cervical
ganglionectomy (SCGx) were examined in male rats. A 12-fold increase of circulating
ACTH was found in both SCGx and
sham-operated rats 6 h after surgery. In
sham-operated rats, plasma
ACTH decreased by about half 16-22 h after surgery, whereas in SCGx rats it remained at a high concentration from 16 to 54 h after surgery, attaining basal values by 120 h post-SCGx. In SCGx rats, MBH
corticotropin-releasing hormone (CRH) content decreased significantly from 16 to 54 h after surgery, while in controls it remained unmodified. Significantly smaller
arginine vasopressin (AVP) contents were found in MBH of SCGx rats as compared to
sham-operated controls, 16-54 h after surgery. In rats exposed to
ether or immobilization stress 22 h after SCGx, plasma
ACTH levels were significantly higher than in controls; however, since unstressed
ACTH levels were about twice as high in SCGx rats, the percent increase of
ACTH was smaller in the SCGx group. A decreased response of plasma
ACTH to
ether or immobilization stress was found in rats 7 days after SCGx. In rats subjected to a simultaneous
adrenalectomy (Adx) and SCGx or
sham-SCGx, plasma
ACTH levels increased to a similar extent in both groups.
ACTH increase after Adx was accompanied by decreases in MBH CRH, and absence of significant changes in MBH AVP contents. Rats subjected to
pinealectomy (Px) or
sham-Px 1 week earlier and killed 22 h earlier exhibited similar responses in plasma
ACTH and MBH CRH to SCGx regardless of pineal intactness.(ABSTRACT TRUNCATED AT 250 WORDS)