Effect of octapeptide: FSH binding inhibitor on cyclicity of bonnet monkeys (Macaca radiata).
BACKGROUND
The gonadotropins follicle-stimulating hormone (FSH) and luteinizing hormone play an important role in the development of ovarian follicles, and a number of autocrine/paracrine factors secreted by the ovary are known to directly or indirectly regulate gonadotropin action. The objective of the present study was to elucidate the effect of octapeptide (OP) on cyclicity and hormonal profile of bonnet monkeys, the menstruating Old World primates.


METHODS
Our group has purified one such factor from human ovarian follicular fluid, which inhibits the binding of FSH to the granulosa cells. N-terminal eight-amino-acid sequence of this peptide has been deduced, which is referred to as the OP. It has shown an antifertility effect in marmosets, the New World primates. In the present study, the bonnet monkeys were divided into two groups, namely, the treated group (n=5), which was administered with OP (250 mcg/kg body weight/day) intramuscularly during the follicular phase, and the control group (n=6), which was injected with vehicle (saline). Blood was collected every other day, and progesterone levels were estimated by enzyme-linked immunosorbent assay.


RESULTS
Animals in the control group demonstrated normal plasma progesterone levels and exhibited normal cyclicity. On the other hand, in the treated group, progesterone levels decreased by 65.8%, as compared with that in pretreatment cycles. This probably disturbed the cyclicity, thus causing amenorrhea (73.0+/-6.7 days).
National Institute for Research in Reproductive Health, Indian Council of Medical Research, Parel, Mumbai 400 012, India.
Swati
S
Kulkarni-Chitnis
Tarala
T
Nandedkar
D000818:Animals; D002352:Carrier Proteins / Q000502:physiology*; D016022:Case-Control Studies; D005260:Female; D005640:Follicle Stimulating Hormone / Q000037:antagonists & inhibitors*; D006107:Granulosa Cells / Q000502:physiology*; D008255:Macaca radiata; D008597:Menstrual Cycle / Q000187:drug effects / Q000502:physiology*; D034445:Ovulation Inhibition / Q000502:physiology; D010446:Peptide Fragments / Q000502:physiology*; D011374:Progesterone / Q000502:physiology*; D011962:Receptors, FSH / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000502:physiology*
D002352:Carrier Proteins; D010446:Peptide Fragments; D011962:Receptors, FSH; C527501:alanyl-glutamyl-seryl-asparagyl-glutamyl-aspartyl-glycyl-tyrosine; D011374:Progesterone; D005640:Follicle Stimulating Hormone