Transplantation of the pituitary pars distalis induces the corticotrophs to store melanocyte-stimulating hormone, an effect reversed by the administration of corticotropin-releasing factor.
Corticotrophs of the pituitary pars distalis do not contain immunohistochemically detectable alpha-melanocyte-stimulating hormone (MSH). After grafting the glands beneath the renal capsule for 25 days, this hormone could be demonstrated in corticotrophs, coexisting with corticotropin. The administration of corticotropin-releasing factor deprived these cells of the content of MSH but did not apparently affect the presence of adrenocorticotropin (ACTH). It is suggested that the histological appearance of MSH in the corticotrophs may be due to a diminished rate of corticotropin release, which may provide time for splitting the former hormone in amounts larger than the negligible ones normally present in the pars distalis, or to the hypothetical fact that some hypothalamic factor may inhibit the cleavage of ACTH into MSH.
Iturriza
F C
FC
Centro de Estudios Endócrinos, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Argentina.
Ferese-Spinelli
C G
CG
D000324:Adrenocorticotropic Hormone / Q000378:metabolism*; D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D005260:Female; D007016:Hypophysectomy; D007150:Immunohistochemistry; D007668:Kidney; D009074:Melanocyte-Stimulating Hormones / Q000378:metabolism*; D010902:Pituitary Gland / Q000637:transplantation*; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D016042:Transplantation, Heterotopic
D000324:Adrenocorticotropic Hormone; D009074:Melanocyte-Stimulating Hormones; D003346:Corticotropin-Releasing Hormone