The mitogenic effects of corticotrophin-releasing factor on the anterior pituitary gland of the rat.
The immunohistochemically defined corticotroph population in the anterior pituitary gland of the adult male Sprague-Dawley rat has been quantified at 2 and 6 weeks after bilateral adrenalectomy using the stereological measurement, volume density (Vv). An approximately twofold increase in corticotroph Vv was demonstrated at 2 weeks in adrenalectomized rats compared with that in sham-operated controls and this was maintained at 6 weeks. Daily i.p. injections of ovine corticotrophin-releasing factor (CRF-41) induced a significant dose-related increase in corticotroph Vv when administered at doses of 25 and 50 micrograms/kg body weight, but this was less than the increase following adrenalectomy. Assessment of changes in mitotic activity of the total anterior lobe of adult Sprague-Dawley rats and of the corticotroph population was also made after daily i.p. injections of 50 micrograms CRF-41/kg for 2 and 7 days. There was no increase in overall mitotic index at either time. However, the numbers of mitotic corticotrophs were significantly increased in CRF-injected animals compared with those in saline-injected rats. These results indicate a role for CRF-41 in the regulation of corticotroph growth.
McNicol
A M
AM
University of Department of Pathology, Royal Infirmary, Glasgow.
Kubba
M A
MA
McTeague
E
E
D000315:Adrenalectomy; D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D008297:Male; D008934:Mitogens; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
D008934:Mitogens; D003346:Corticotropin-Releasing Hormone