Chromogranin A proteolysis to generate beta-granin and WE-14 in the adenohypophysis during the rat oestrous cycle.
Immunohistochemical analysis of the male and female rat adenohypophysis revealed that chromogranin A (CgA), beta-granin and WE-14 immunostaining was localised to follicle stimulating hormone (FSH) producing cells, while luteinizing hormone (LH) producing cells exhibited chromogranin A and beta-granin immunostaining. The intensity of chromogranin A, beta-granin and WE-14 immunostaining exhibited variation during the oestrous cycle; weak immunostaining was observed during proestrous and oestrous, corresponding with the lowest cellular concentration of luteinizing and follicle stimulating hormone. Chromogranin A and beta-granin immunostaining were similar in both the male and female (at dioestrous), however, a larger number of more intense WE-14 immunopositive cells were evident in the male adenohypophysis relative to the female at any stage of the cycle. The tissue and plasma concentrations of beta-granin and WE-14 immunoreactivity fluctuated throughout the oestrous cycle. Maximum and minimum beta-granin and WE-14 tissue concentration counterpoised the latent maximum and minimum plasma concentration. Chromatographic analysis of adenohypophysis extracts revealed the degree of chromogranin A proteolysis throughout the oestrous cycle; in contrast, plasma profiles consistently possessed a large chromogranin A-like immunoreactant. This data suggests that chromogranin A biosynthesis, proteolysis and the secretion of its derived peptides parallels that of the gonadotroph hormones throughout the oestrous cycle.
McVicar
Carmel Mary
CM
School of Medicine, Obstetrics and Gynaecology, Queen's University of Belfast, Institute of Clinical Science, Grosvenor Road, Belfast, BT12 6BJ, Northern Ireland, UK. c.mcvicar@qub.ac.uk
Cunningham
Rodat Therese
RT
McClure
Neil
N
Curry
William James
WJ
D000818:Animals; D002845:Chromatography; D053379:Chromogranin A; D002864:Chromogranins / Q000378:metabolism* / Q000494:pharmacology*; D030762:Estrous Cycle; D005260:Female; D005640:Follicle Stimulating Hormone / Q000378:metabolism; D007150:Immunohistochemistry; D007986:Luteinizing Hormone / Q000378:metabolism; D008297:Male; D009363:Neoplasm Proteins / Q000378:metabolism*; D010903:Pituitary Gland, Anterior; D011499:Protein Processing, Post-Translational; D011863:Radioimmunoassay; D051381:Rats; D017208:Rats, Wistar
D053379:Chromogranin A; D002864:Chromogranins; D009363:Neoplasm Proteins; C046560:beta-granins; C506153:chromogranin A, rat; C074381:chromogranin A-derived peptide, WE-14; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone