Comparison of the response in vivo to luteinizing hormone and follicle stimulating hormone of the granulosa of six follicles from the ovarian hierarchy in the chicken (Gallus domesticus).

A function test was used to compare the response of the granulosa from the six largest preovulatory follicles. F1-F6, of laying hens to ovine LH (40 micrograms), ovine FSH (1200 micrograms), and PMSG (800 micrograms). The progesterone content of these granulosa which were dissected out exactly 45 min after the injection, was measured by radioimmunoassay. With each of the three gonadotropin preparations, the amount of progesterone accumulating in the F1-F3 granulosa always exceeded that of F4 and F5. The values were two to six times greater than those obtained in tissue from control hens injected with 1% bovine serum albumin (BSA). The levels in the smallest F6 granulosa did not differ from those of BSA-treated controls. LH had the greatest stimulatory effect on the granulosa response. The results indicate that the production of progesterone by the granulosa of the F1-F5 follicles in vivo may be controlled mainly by LH, rather than FSH. The observed changes induced by the FSH and PMSG preparations could be attributed to their LH content. The granulosa of the F1 and F2 follicles are the major contributors to the circulating progesterone in the blood plasma of the laying hen.