The effect of ovine corticotrophin-releasing factor on the hormonal response to insulin-induced hypoglycaemia.
In order to investigate the role of hypothalamic corticotrophin-releasing factor (CRF41) in the mediation of the pituitary ACTH response to hypoglycaemia, eight normal adult males were studied on four occasions. Commencing at 0830 h after an overnight fast, each received, in double-blind, random order, intravenous boluses of: A, normal saline control; B, soluble insulin 0.15U/kg; C, ovine CRF41 (oCRF41) 100 micrograms; D, soluble insulin 0.15U/kg followed immediately by oCRF41 100 micrograms. Adequate hypoglycaemia (blood glucose less than 2.2 mmol/l) was achieved in each subject when insulin was given alone or with oCRF41, and there was no difference in the glucose nadir between the 2 days. Peak plasma ACTH was significantly higher after insulin plus oCRF41 than after insulin alone (P less than 0.05) or oCRF41 alone (P less than 0.01) and this enhancement of ACTH release was most marked in the first phase of the response at 30 min (P less than 0.001, b vs d). There was no difference in the peak serum cortisol response whether oCRF41 and insulin were given alone or together and although the area under the cortisol curve was greater after insulin plus oCRF41, this difference was explicable simply on the basis of the earlier onset of the cortisol response to oCRF41. There were no differences in the serum GH responses to hypoglycaemia on the 2 days.(ABSTRACT TRUNCATED AT 250 WORDS)
Howlett
T A
TA
Department of Endocrinology, St Bartholomew's Hospital, London.
Grossman
A
A
McLoughlin
L
L
Perry
L
L
White
A
A
Coy
D H
DH
Rees
L H
LH
Besser
G M
GM
D000324:Adrenocorticotropic Hormone / Q000097:blood*; D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D004311:Double-Blind Method; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007003:Hypoglycemia / Q000097:blood* / Q000209:etiology; D007328:Insulin; D008297:Male; D011897:Random Allocation
D001786:Blood Glucose; D007328:Insulin; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D006854:Hydrocortisone