Circulating radioimmunoassayable inhibin during periods of transient follicle-stimulating hormone rise: secondary surge and unilateral ovariectomy.
We have measured changes in circulating immunoreactive (ir-) inhibin in male and female rats using an RIA with an antiserum raised against porcine inhibin alpha (1-26)-Gly-Tyr. The same synthetic peptide was used for standards and for the preparation of tracer. Serum ir-inhibin levels were significantly higher in intact female than in intact male rats (p less than 0.001). Immunoreactive inhibin was significantly reduced in both sexes 24 h after bilateral gonadectomy (p less than 0.0001). Unilateral ovariectomy (ULO) of female rats on metestrus caused a transient decrease in serum inhibin 8 h after surgery, but levels were not significantly different from those of sham-operated controls at later times after surgery. Increases in serum FSH and LH were observed for 8-18 h after ULO. Serum ir-inhibin levels were also measured on the early morning of estrus during the secondary FSH surge. At this time, ir-inhibin levels were low, while FSH levels were high and LH levels were low. These results show that serum ir-inhibin levels in rats are decreased at times when serum FSH levels are high.
Ackland
J F
JF
Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois 60208.
D'Agostino
J
J
Ringstrom
S J
SJ
Hostetler
J P
JP
Mann
B G
BG
Schwartz
N B
NB
D000818:Animals; D004971:Estrus / Q000097:blood; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood*; D007265:Inhibins / Q000097:blood*; D007700:Kinetics; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D009919:Orchiectomy; D010052:Ovariectomy; D011359:Proestrus / Q000097:blood; D011374:Progesterone / Q000097:blood; D051381:Rats; D011919:Rats, Inbred Strains
D011374:Progesterone; D007265:Inhibins; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone