Cholecystokinin varies in the posterior pituitary and external median eminence of the rat according to factors affecting vasopressin and oxytocin.
Using radioimmunoassay (RIA), the content of gastrin-cholecystokinin family peptide immunoreactivity (G-CCK-IR), in the posterointermediate lobe (PIL) of the rat pituitary, has been determined in several experimental conditions. G-CCK-IR levels are significantly higher in males than in females. Salt loading induces a significant decrease of G-CCK-IR in animals of either sex. In males, G-CCK-IR levels are lower than controls 21 days after either castration or daily subcutaneous oestradiol injections. Using immunocytochemistry, G-CCK-IR disappears from the external median eminence 21 days after adrenalectomy. Our results show that, in addition to sex difference, factors affecting the vasopressin and/or oxytocin levels in the posterior pituitary and external median eminence also affect G-CCK-IR in the same regions. Cholecystokinin may therefore be of importance in functions related to these hormones.
D000315:Adrenalectomy; D000818:Animals; D002369:Castration; D002766:Cholecystokinin / Q000378:metabolism*; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology; D005260:Female; D005755:Gastrins / Q000378:metabolism*; D008297:Male; D010121:Oxytocin / Q000378:metabolism*; D010904:Pituitary Gland, Posterior / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012737:Sex Factors; D012965:Sodium Chloride / Q000494:pharmacology; D014667:Vasopressins / Q000378:metabolism*
D005755:Gastrins; D014667:Vasopressins; D012965:Sodium Chloride; D004958:Estradiol; D010121:Oxytocin; D002766:Cholecystokinin