Sex and strain variability in the rat hypothalamo-pituitary-adrenal (HPA) axis function.
In the present investigation, we examined the influence of both genetic background and sex factors in the rat hypothalamo-pituitary-adrenal (HPA) axis function under both basal and post adrenalectomy (ADX) conditions. For these purposes adult female and male rats, from Sprague-Dawley (S-D), Fischer (F344/N), Lewis (LEW/N) and Buffalo (BUF) strains, were decapitated in basal condition or several (2, 7 and 14) days after ADX. Plasma stress hormones levels and adrenal corticosterone (B) concentration as well as peptide (ACTH, CRH and vasopressin, AVP) content in different tissues (anterior pituitary, AP; medial basal hypothalamus, MBH), were then evaluated by specific assays. Our results indicate that: a) despite no sex- and strain-related differences in AP ACTH and MBH ACTH secretagogues in basal condition, there exits a clear sexual dimorphism in plasma ACTH levels as well as in both plasma and adrenal B concentrations, with values significantly higher in females than in males, regardless the strain; b) ADX abolished plasma B levels and increased AP ACTH output in a time-dependent fashion up to the 14th day post surgery; c) AP ACTH content decreased 2 days after ADX, except in BUF female rats, thereafter tending to either recover or increase sham values by two weeks post ADX; d) ADX decreased MBH CRH at all periods studied, except in BUF female animals on day 14; e) ADX clearly diminished MBH AVP only in S-D rats, and f) a sexual dimorphism was also found in AP ACTH in 7-day-ADX S-D rats and in 14-day-ADX S-D and F344/N animals; also, a dimorphic pattern in MBH CRH was found in 7-day-ADX S-D as well as in 14-day-ADX F344/N and LEW/N rats.(ABSTRACT TRUNCATED AT 250 WORDS)
Chisari
A
A
Department of Neuroscience, Multidisciplinary Institute on Cell Biology, La Plata, Argentina.
Carino
M
M
Perone
M
M
Gaillard
R C
RC
Spinedi
E
E
D000311:Adrenal Glands / Q000502:physiology*; D000315:Adrenalectomy; D000324:Adrenocorticotropic Hormone / Q000378:metabolism; D000818:Animals; D001127:Arginine Vasopressin / Q000378:metabolism; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism; D005246:Feedback; D005260:Female; D007031:Hypothalamus / Q000502:physiology*; D008297:Male; D010902:Pituitary Gland / Q000502:physiology*; D010903:Pituitary Gland, Anterior / Q000378:metabolism; D051381:Rats; D011915:Rats, Inbred BUF; D011916:Rats, Inbred F344; D011917:Rats, Inbred Lew; D017207:Rats, Sprague-Dawley; D012727:Sex Characteristics; D013045:Species Specificity
D001127:Arginine Vasopressin; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone