Stimulation of pituitary corticotrophs in the rat--ultrastructural studies.
The ultrastructural changes occurring in the corticotrophs of adult male and female Sprague-Dawley rats at 2 and 6 weeks after bilateral adrenalectomy were assessed on both a qualitative and quantitative basis. Qualitative changes were similar to those previously described but at both time points, female rats showed more marked changes than males. Corticotroph hypertrophy reached a plateau in male animals between 2 and 6 weeks, but continued to increase in females. There was an increase in mean granule diameter in both sexes at 2 weeks after adrenalectomy. The changes induced by the daily administration of CRF for 2 weeks by intraperitoneal injection were also examined in male rats. CRF induced corticotroph hypertrophy at both 25 micrograms/Kg and 50 micrograms/Kg body weight and increased the granule content. The addition of vasopressin (VP) to the higher dose of CRF induced a further increase in cell area and reduction in granule content. Low dose CRF was associated with an increase in mean granule diameter, whereas a decrease was seen after high dose.
D000315:Adrenalectomy; D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D008297:Male; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000648:ultrastructure*; D051381:Rats; D011919:Rats, Inbred Strains; D012737:Sex Factors; D014667:Vasopressins / Q000494:pharmacology
D014667:Vasopressins; D003346:Corticotropin-Releasing Hormone