Activation of the hypothalamo-anterior pituitary corticotropin-releasing hormone, adrenocorticotropin hormone and beta-endorphin systems during the estradiol 17 beta-induced plasma LH surge in the ovariectomized monkey.
The present work describes time-dependent changes in the content of corticotropin-releasing hormone (CRH), adrenocorticotropin (ACTH), and beta-endorphin (beta-EP) in the hypothalamus (HT) and anterior pituitary (AP) and in the concentration of ACTH and beta-EP in the plasma during the 17 beta estradiol (E2) benzoate (E2B)-induced luteinizing hormone (LH) surge in ovariectomized cynomolgus monkeys. Monkeys were euthanized at 0, 30, 48, 72, and 96 hr post-E2B. HT and AP were rapidly dissected, extracted in 2 N acetic acid containing 1 mM phenylmethane sulfonyl fluoride at 4 degrees C, and centrifuged at 18,000g for 30 min. Peptide concentrations were measured in the supernatant by specific radioimmunoassays (RIAs). In the HT, there were significant (P < 0.05) decreases in ACTH and beta-EP content by 30 hr post-E2B and a significant (P < 0.05) decrease in HT CRH content 48 hr post-E2B. Thereafter, CRH, ACTH, and beta-EP content increased up to 72 hr post-E2B. In the AP, there was an almost linear decrease in the CRH content through 48 hr post-E2B followed by a marked 20-fold (P < 0.01) increase in the AP CRH content at 72 hr post-E2B, which corresponds to the time of the descending arm of the LH surge. The patterns of ACTH and beta-EP content were very similar in the AP, while that of CRH differed markedly. In contrast, in the HT CRH, ACTH, and beta-EP profiles were very similar. Significant (P < 0.05) increases in circulating levels of ACTH, beta-EP, and cortisol were evident at 30 hr (all 3 hormones), 48 hr (beta-EP and cortisol), and 72 hr (cortisol) post-E2B, which corresponds with the time of decreased hypothalamic content of CRH, ACTH, and beta-EP. These results suggest that there maybe a marked activation of the hypothalamo-anterior pituitary-adrenal axis during the negative and positive feedback phases of the E2B-induced LH surge in the ovariectomized monkey.
Kerdelhué
B
B
Laboratoire de Neurobiologie de la Reproduction, CNRS, Jouy-en-Josas, France.
Jones
G S
GS
Gordon
K
K
Seltman
H
H
Lenoir
V
V
Mélik Parsadaniantz
S
S
Williams
R F
RF
Hodgen
G D
GD
D000324:Adrenocorticotropic Hormone / Q000096:biosynthesis* / Q000235:genetics; D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000096:biosynthesis* / Q000235:genetics; D004958:Estradiol / Q000494:pharmacology*; D004971:Estrus; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D006854:Hydrocortisone / Q000096:biosynthesis; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects* / Q000378:metabolism; D007986:Luteinizing Hormone / Q000378:metabolism*; D008252:Macaca fascicularis; D010052:Ovariectomy; D001615:beta-Endorphin / Q000096:biosynthesis* / Q000235:genetics
D004958:Estradiol; D001615:beta-Endorphin; D000324:Adrenocorticotropic Hormone; D007986:Luteinizing Hormone; D003346:Corticotropin-Releasing Hormone; D006854:Hydrocortisone