Effects of galanin on the secretion and proliferative activity of the immature and regenerating adrenal glands of rats.
The effects of galanin and the galanin-receptor antagonist (galanin-A) [D-Thr(6),D-Trp(8,9),15-ol]-galanin(1-15) on the immature and regenerating rat adrenal glands have been investigated in vivo. Adult female rats with adrenal regeneration and their offpring (20-day-old) were given three subcutaneous injections (28, 16, and 4 h before being killed) of 2 nmol/100 g galanin and/or galanin-A, and 0.1 mg/100 g vincristin 3 h before being killed. Plasma corticosterone concentration was measured by radioimmunoassay, and the mitotic index ( per thousand of metaphase-arrested cells) was evaluated. In immature rats, galanin increased plasma corticosterone concentration, without affecting mitotic index; the secretagogue effect was reversed by galanin-A, which alone was ineffective. In rats with regenerating adrenal, galanin-A increased both blood level of corticosterone and mitotic index; galanin was ineffective, but blocked the effects of galanin-A. These findings allowed us to draw the following conclusions: 1) galanin exerts a moderate glucocorticoid secretagogue action on immature rat adrenals, but endogenous galanin does not play a major physiological role in the functional control of the gland; and 2) endogenous galanin exerts a maximal tonic inhibitory control on both glucocorticoid secretion and proliferative activity of regenerating rat adrenals, whose physiological relevance remains to be investigated.
Hochól
A
A
Department of Histology and Embryology, School of Medicine, PL-60781, Poznan, Poland.
Neri
G
G
Jêdrzejczak
N
N
Trejter
M
M
Markowska
A
A
Nussdorfer
G G
GG
Malendowicz
L K
LK
D000311:Adrenal Glands / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D000818:Animals; D002455:Cell Division / Q000187:drug effects; D003345:Corticosterone / Q000097:blood; D005260:Female; D019004:Galanin / Q000031:analogs & derivatives / Q000494:pharmacology*; D008940:Mitotic Index / Q000187:drug effects; D010446:Peptide Fragments / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D044088:Receptors, Galanin; D018013:Receptors, Neuropeptide / Q000037:antagonists & inhibitors; D012038:Regeneration / Q000187:drug effects
D010446:Peptide Fragments; D044088:Receptors, Galanin; D018013:Receptors, Neuropeptide; D019004:Galanin; D003345:Corticosterone